To appear in Journal of the History of Philosophy

Schlick and Wittgenstein: The Theory of Affirmations Revisited

thomas.uebel@manchester.ac.uk

Abstract: Viewed from the perspective of the epistemology of science, Schlick’s theory of affirmations was an obvious failure. Most interpreters either reject his conception wholesale or save only parts of it for the price of discarding others. This paper investigates whether it is possible to provide a more favourable reading by placing Schlick’s affirmations in a broader interpretive framework than the Viena Circle’s protocol sentence debate, namely his longstanding concern with scepticism. It will be argued that reading Schlick’s affirmations as an attempt to improve his old, pre-Vienna Circle response to skepticism by the new means which his discussions with Wittgenstein and familiarity with his unpublished writings made available does possess plausibility as an interpretation of authorial intentions. Yet while this reading makes better sense of Schlick’s theory of affirmations than common attributions of foundationalist ambitions, it must also be conceded that ultimately it does not “save” his theory either.

1.. Introduction. The ready availability of Wittgenstein’s previously unpublished writings from his so-called middle period of ca. 1929 to 1936 has greatly aided the understanding of the development of his thought. For obvious reasons it has had little effect on the interpretation of Wittgenstein’s contemporaries. Even of those who had by then taken note of the Tractatus Logcico-Philosophicus, very few were apprized of the new avenues Wittgenstein’s thought had begun to take. One such rare exception was Moritz Schlick, the nominal head of the Vienna Cirle and an eminent philosopher of science (the first to publish knowledgeably about Einstein’s theories of relativity). Still before Wittgenstein’s return to philosophy in 1929 Schlick became a valued interlocutor for him and remained so until his death.1 It is well known that under the influence of the Tractatus Schlick’s focus of interests underwent significant change. Here my concern is to investigate how far Schlick’s familiarity with Wittgenstein’s new ways of

1 See Iven (2015) for their correspondence and Engler (2015) for a suggestive reconstruction of their discussions—which were ended by Schlick’s murder in 1936.

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thinking may help to make sense of the most puzzling chapter of his own later philosophy, his theory of affirmations (“Konstatierungen”).

Viewed from the perspective of the epistemology of science, Schlick’s theory of affirmations was an obvious failure.2 Schlick intended affirmations to be observation statements that were not identical with the protocol statements recordable by scientists in the course of their work. Conceived of as statements that were incorrigible—albeit only if affirmed sincerely—they were held to constitute a class (the only one) of synthetic statements where understanding of their sense coincided with recognition of their truth. This remarkable characteristic of affirmations was explained by them employing (i) indexical expressions that were held to be irreplaceable by coordinate expressions or proper names and (ii) descriptive expressions the use of which was not constrained by prior usage but only the user’s intentions at the time. Schlick’s theory was unable to resolve the tension between the contradictory presuppositions that must be made in order, on the one hand, to provide for the subjective certainty affirmations meant to afford our knowledge claims and, on the other hand, to provide for the objective legitimation that scientific knowledge claims require. Interpreters either reject the theory wholesale or save only part of it for the price of discarding some other property that affirmations supposedly possessed.3

The question arises whether Schlick’s theory should be considered from an altogether different perspective, contrary to common practice. Two considerations suggest this. First, Schlick repeatedly addressed as pertinent to the issue of affirmations the question of the criterion of truth—even though his opponents were concerned primarily with the issue of the content, the form and the epistemological status of so-called protocol statements (scientific evidence statements) but not what their truth consisted in. Second, for Schlick it was unquestionable that there existed certain and incorrigible foundations of human knowledge. That science did not provide these was of no consequence to him.

2 By “theory of affirmations” is meant Schlick’s conception of the statements grounding our knowledge claims as first published in "Über das Fundament der Erkenntnis." (“On the Foundation of Knowledge”) (1934)—after he had developed it in outline in his lecture course “Die Probleme der Philosophie in ihrem Zusammenhang“ (“The Problems of Philosophy in their Interconnection”) in the winter semester 1934/35 (1986/87)—and further elaborated in “Facts and Propositions” (1935a), his response to criticism by C.G. Hempel, and defended in “Introduction [to Sur le Fondement de Connaissance]” (1935b) and “Sur les ‘Constatations’” (1935c). 3 This diagnosis and Schlick’s position the Vienna Circle’s protocol-sentence debate is elaborated in Uebel (2007, Chs. 9-10) where further references to the literature can be found. In a recent work on the matter by Friedl (2013) it is stated that Schlick himself never offered a wholly unified and comprehensive presentation of his theory and that Schlick’s thought on the matter remained unfinished. That is correct but is of no help to Schlick. For precisely concerning affirmations Schlick always expressed himself quite categorically and no remarks of his have been preserved, as far as I know, that cast doubt on the basic idea of this theory.

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Schlick was not the only philosopher of his time who insisted that knowledge in some sense entailed certainty. In his Problems of Philosophy Russell regarded scientific knowledge as merely probable opinion (1912, Ch. 13). But the influence of Russell’s one-time student Wittgenstein looms largest here: after his return to philosophy and well into the 1930s, much of Wittgenstein’s thinking, when not preoccupied with mathematics, concerned what we could not be mistaken about, immediate experience, and its relation to human discourse generally. Can a more favourable interpretation of Schlick’s theory of affirmations be provided by relating it more closely to the views and ideas of Wittgenstein which at the time were in constant flux?4 Wittgenstein’s path from the Tractatus to the mature formulations of his Philosophical Investigations is marked by a large number of notebooks, manuscripts and typescripts and various revisions of the latter. The important task of determining which of the intermediate positions and formulations were known to Schlick—and when—has not been completed yet but it is possible at least to get started on the matter.5

Yet the influence of Wittgenstein is only one element here, for I also wish to bring the early and later Schlick into closer philosophical contact than is common. Thus I shall consider whether what looks like Schlick’s turning away from philosophy of science in the strict sense was not also a return to a more traditional philosophical topic that had concerned him already early on. The alternative interpretation of Schlick’s theory of affimations here offered for consideration sees him trying to rework his early response to the challenge of skepticism with the tools which his familiarity with Wittgenstein’s unpublished writings made available.6

2.. Schlick’s Theory of Affirmations. The diagnosis of the failure of Schlick’s theory can be further sharpened by recalling typical theses and tropes before turning to the alternative interpretation.

Not only the title of Schlick’s paper but also the text, indeed the very first sentence, indicates that its author found nothing wrong with “the wish for

4 Even Wittgenstein’s late On Certainty (1969b) shows him concerned to arrive at a proper understanding of (Moorean) certainties—not to argue against them. 5 For the advances, see Iven (2010) and Manninen (2011). As for the unresolved questions, note first their disagreement about the dating of the “Diktat für Schlick” (see fn. 16 below). Another unresolved issue is that the date of Schlick’s receipt of his copy of the “Blue Book” (kept in the Forschungsstelle für österreichische Philosophie, Universität Graz) remains unclear. A letter from Alice Ambrose to Schlick of 19 December 1934 refers to “dictated notes which Wittgenstein had sent to him” and asked whether he wished to receive further supplementary notes, and a postcard from her, apparently of May 1935, requests their return by July. That the “Blue Book” (published in 1958 but dictated by Wittgenstein in the academic year 1933/34) is at issue seems clear but the identity of the supplementary notes can only be guessed to be that of the so-called “Yellow Book (1979; notes of discussions in the intervals between dictations of the “Blue Book”).6 Nota bene: I seek to present and develop this interpretation here but not to defend it against all comers—for reasons that will become apparent at the end.

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absolute certainty of knowledge”, the search “for an unshakable foundation, immune from all doubt and forming the firm basis on which the tottering edifice of our knowledge is reared”, “for the natural bedrock which is there before building commences, and does not itself sway” (1934/1979, 370). According to him, this question had also been raised in the Vienna Circle itself: “The question of ‘protocol propositions’, their function and structure, is the latest form in which... the decisive empiricism of our day invests the problem of the ultimate ground of knowledge.” (Ibid.) But Schlick believed that in this respect the protocol sentence debate had taken the wrong turn. “For as soon as one asks about the certainty with which one may maintain the truth of protocol propositions regarded in this fashion, one has to admit that it is exposed to all manner of doubt.” (Ibid., 373) Schlick rejected the universal fallibilism which the “physicalists” Neurath and Carnap had by then come to agree upon.7

“[I]ts essential defect consists in failing to recognize the differing status of propositions, most clearly revealed in the fact that for the system of knowledge which anyone accepts as the ‘correct’ one, his own propositions still ultimately play the only decisive role.” (Ibid., 379, orig. emphasis)

Schlick rejected universal fallibilism because he also rejected the deconstruction of the epistemic autonomy of the individual author or bearer of scientific knowledge.

One key to his alternative conception lies in the replacement of the static picture of science as a system of propositions with the dynamic picture of a process of inquiry.

“The question concealed behind the problem of the absolute certain foundation of knowledge is, so to speak, that of the legitimacy of the satisfaction which verification fills us with. … Finality is a very suitable word to describe the significance of observation statements. They are an absolute end, and in them the current task of knowledge is fulfilled. Science does not rest on them, but leads to them, and they show that it has led aright. They are the absolutely fixed points; we are glad to reach them, even if we cannot rest there.” (Ibid., 383, orig. emphasis)

This is an unusual response to the traditional question. Absolute certainty is granted to us, but it has no permanence. Schlick summarized his reorientation as follows:

“If we turn our attention to the connection of science with reality, and see in the system of its propositions what it really is, namely a means

7 Positions had been different still in 1930 when Schlick first adumbrated what here will be called his “proto-theory” of affirmations; see sect. 5 below.

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of orienting oneself among the facts, of attaining to the joy of confirmation, the feeling of finality, then the problem of the ‘foundation’ will automatically transform itself into that of the unshakable points of contact between knowledge and reality. These are the absolutely fixed points, the affirmations, we have come to know in their particularity; they are the only synthetic propositions which are not hypotheses.” (Ibid., 386-387, orig. emphasis)

The change in Problemstellung may be put like this. The question ‘What is the absolute certain foundation of knowledge?’ is no longer understood as a meaning-theoretical question in what came to be called the “semantic” dimension that grounds propositions. Instead the question attends to the pragmatic dimension of use and user. The “unshakable points of contact between knowledge and reality” answer a need of knower. Thus the task is set for affirmations:

“In no sense do they lie at the basis of science, but knowledge, as it were, flickers out to them, reaching each one for a moment only, and at once consuming it. And newly fed and strengthened, it then flares on toward the next.These moments of fulfillment and combustion are of the essence. From them comes all the light of knowledge. And it is this light for whose source the philosopher is actually asking, when he seeks the foundation of all knowledge.” (Ibid., 387).

Schlick was extremely serious about what to many readers looks like purple prose. When Neurath questioned the “poetry” of this death-and-rebirth metaphor (1934/1983, 114) Schlick was so deeply offended that he broke off all further discussion with him and never again mentioned his name in publication (even when he issued barbs in his direction). For Schlick these turns of phrase were not merely rhetorical flourishes: as he understood them, the use of these very special sentences revealed a deep insight of philosophical anthropology about the motivational point of the exercise of human capabilities. (“Affirmation”, it turns out, is a fitting translation of “Konstatierungen”.)

Because of this quasi-pragmatic turn Schlick was able to answer at least one tricky question arising from his conception of affirmations. In response to a criticism by Carnap, Schlick pointed out that affirmations are not meant to aid the derivation of protocol statements since they do not belong to the language of science: “They do not occur within science itself, and can neither be derived from scientific propositions, nor the latter from them …” (1935b/1979, 407; cf. 1935c/1979, 409). And he continued:

“they are therefore ignored by those who are interested only in logical deductions, the internal rational concerns of science. Yet they play the most important role of all in the psychological issue concerning the

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foundations of all knowledge. It is this role that which I have tried to depict in [‘On the Foundation of Knowledge’].” (1935b/1979, 407)

Here Schlick clearly stressed that his concern did not lie within the Carnapian discipline of the logic of science: neither the old problem of the absolutely certain foundation of knowledge nor the new problem of the unshakable points of contact between knowledge and reality find a place there.

In his final contribution to the debate Schlick reaffirmed that there exists a class of statements that possess precisely those rules which he attributed to affirmations:

“There is thus a use of such sentences as ‘Yellow here’, ‘There are two lines in the visual field’, etc., in which it would be absurd (that is, contrary to the accepted rules), to speak of error or deception: and where this usage prevails, I call the statement ‘affirmation’. All statements having the character of hypotheses can be false on two, and only two, grounds: either an error is present, or a lie. But a false affirmation is always a lie—that is simply logical rule which applies to it.” (1935c/1979, 409-410, orig. emphasis)

It was Wittgenstein’s concept of grammar which allowed Schlick to sharpen and render more precise his earlier comparison (in “On the Foundation of Knowledge”) between analytical statements and affirmations. Schlick also returned to his earlier short dismissal of another fallibilist objection, that there is no guarantee that I understood a proposition correctly.

“I could indeed be the victim of a deception of memory. But just as in the case of an affirmation, such a doubt does not give rise to that uncertainty which is characteristic of a hypothesis, for it is not a doubt about the truth of a given proposition, but rather about whether the way I have chosen to present the proposition obeys the symbolic rules that are otherwise customary. … Perhaps it is quite untrue that I have always called the colour ‘yellow’; if so, there is indeed a deception of memory, but even in this case, the affirmation remains true (so long as a lie is not in question). Its truth does not depend on how I have otherwise really employed the words, but only on how I think at this moment that I have employed them. But I cannot be mistaken about that …” (Ibid., 412)

At this point Schlick meets with the central difficulty which my aforementioned diagnosis focuses upon. How can a momentary understanding of linguistic expressions which is not bound by their previous usage contribute to the legitimation of knowledge claims for whose formulation the common or agreed upon prior usage is essential? And how likely is it that Schlick did not notice this difficulty? If we think this

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unlikely, we must look for the foundation-providing point of affirmations elsewhere than in the protocol-sentence debate.

But what task might affirmations have if not a strictly scientific one? I propose we follow Schlick’s suggestion in “On the Foundation of Knowledge” that affirmations were set the task of solving the “old” problem with “new” means. The old problem was, as he put it, “the wish for absolute certainty of knowledge” and the search “for an unshakable foundation”, “for the natural bedrock which is there before building commences, and does not itself sway”. All these formulations of the old problem direct us towards the problem of skepticism and its traditionally sought answer. The new means, I’d like to suggest, were those that Wittgenstein put at Schlick’s disposal. Let’s take this step by step.

3.. The “Old” Problem. The problem of skepticism occupied Schlick already in his habilitation dissertation “Das Wesen der Wahrheit nach der neuen Logik” (“The Nature of Truth in Modern Logik”, 1910-11) and he returned to it with renewed emphasis in his main work Allgemeine Erkentnislehre (General Theory of Knowledge, 1918, 2nd ed. 1925).8

In “The Nature of Truth” Schlick argued that truth is unchangeable and multiply detectable and claimed that it is possible to have certain and infallible knowledge, noting, however, that such knowledge concerns only conceptual truths but not common judgments about facts. He recognized verification as the sole criterion of truth and determined it to consist in “establishing that two judgments are identical” (1910-11/1979, 76). Truth was defined as “the one-to-one coordination of judgments with states-of-affairs” (ibid. 95).9 Thus he stated:

“There would thus be no truth for us without the power of assuredly affirming identity, and this therefore constitutes a further indispensable precondition [for knowledge, TU]. We posses this power in a certain degree; it is a fundamental function of the human mind, and it would be vain for us to try to explain it.” (Ibid., 101)

Knowledge demands the capability to make identity judgments with certainty and this capability Schlick believed he could presuppose. Just prior, he had noted two other preconditions. The first limits the epistemological status of factual judgments.

“The regularity of the course of phenomena is the reason why our judgments verify themselves; but since we possess no perfect

8 On the interesting but relatively neglected topic of Schlick and skepticism, see also Popkin (1982) whose treatment focuses only on Schlick’s defense of analytical knowledge and disregards the habilitation dissertation. 9 Importantly, Schlick used “Zuordnung”, not “Übereinstimmung” or any other term meaning correspondence.

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experience of the nature of this regularity, we lack insight … into the necessity whereby ‘truths of fact’ are verified without exception, and are thus unable to arrive at truths in this area except in approximate fashion.” (Ibid., 100-101)

The second precondition concerns conceptual judgments as well. Schlick pointed to,

“the role played by memory, the power of reproduction, even in brief inferences, and in the formation of judgment itself. Kant expresses the same fact, inter alia, in the following words: ‘If we were not conscious that what we think is the same as what we thought a moment before, all reproduction in the series of representations would be useless.’ The earlier is in fact coupled with the later in our unitary consciousness in a perfectly certain manner, in the ‘pure, original, unchanging consciousness’ which Kant calls ‘transcendental apperception’. (Ibid., 101, orig. emphasis)

For Schlick it was legitimate to rely upon memory of earlier conceptualizations and this gave security to the determination of the identity of two judgments in which the process of verifying claims found its conclusion.

It might be thought that this kind of security could also be ascribed to some judgments of fact. Even if universal judgments can at best be considered probable in light of the inductive inference they are based on, every successful verification of a singular judgment should allow us to speak with certainty since it involves the determination of the identity of a prediction and a judgment of observed fact. However, as inductive inference is again seen to be involved in the step from judgments about the given (which was conceived of phenomenalistically) to singular judgments about the facts of the external world, it is impossible to know the latter with certainty. Empirical knowledge thus remained problematical—with one exception:

“The only exception is constituted by perceptual judgments at the moment the perception occurs. But such judgments are of no importance for our knowledge; they are utterly superfluous, since they actually have less content than the perception fully given at the same time.” (Ibid., 88)10

Here in his habilitation Schlick still rejected as unimportant what later will become, as we shall see, of crucial significance.

Schlick’s General Theory of Knowledge offers a related argumentation but goes further into anti-skeptical details. (Once again knowledge was 10 A “perceptual judgment” is a “judgment whereby an actual experience is immediately expressed” (ibid., 75). By contrast, the “content” of a “perception fully given” would appear to involve reference to objects perceived.

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equated with certainty without further ado.) Note also that here Schlick approached the problem with a distinctive pathos that links with the closing passage of “On the Foundation of Knowledge”.

When we stand ... on the highest peak of skepticism, a shudder of intellectual anxiety comes over us. We are seized with dizziness, for we glimpse an abyss that seems bottomless. This is a point at which the paths of the theory of knowledge, of psychology and—as I hope I may add—of metaphysics intersect and suddenly break off. We cannot be satisfied, once we have looked into the abyss of doubt and uncertainty and have drawn back from the brink, merely to return unmoved to the land of common sense. We cannot comfort ourserlves with the thought that such doubts are fruitless and that despite them the sciences enjoy a firmly grounded existence. We do not want to ascend once more into the light of science until we have taken full measure of the depths of the knowing consciousness. Epistemology is not as fortunately situated as the individual sciences, which can leave the verification of their foundations to a more general discipline; the theory of knowledge is concerned precisely with the ultimate presuppositions of all certainty. We can hope to overcome universal doubt only if we strip the difficulty of its wrappings and face it clearly.” (1918-25/1985, 118, orig. emphasis)11

Once again Schlick referred to Kant’s transcendental apperception in order to refute skepticism vis-à-vis analytical inferences, but this time he mentioned an important qualification.

“Naturally there is no assurance that a particular analysis will be performed with full certainty by a particular person.... But this is more than we can ask for. The real question is whether it is possible at all, whether it ever happens that deductions can be carried out with absolute certainty, whether any inference as such is ever safe from the threat of extreme doubt. That the correctness of one or another analysis is assured in the fashion described is something we experience as a fact. But there is no guarantee that we or someone else must experience that fact in the case of any particular analysis. We experience it in certain instances; indeed we can even give empirically the approximate circumstances in which we are accustomed to experience it. And with this we might let the matter rest. For the unlimited power of skepticism is thereby breached.” (Ibid., 129)

For Schlick then the point was not to establish full certainty for all or even only actually undertaken deductions, but only to ensure that it was possible in principle that such certainty can be reached. He concluded: “In general we possess the capability of holding on to our ideas, through a minimal 11 All passages quoted from Schlick’s General Theory are from the first edition.

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period of time, as firmly as is required to carry our analytic inference with full confidence. The unity of consciousness guarantees that.” (Ibid., 130)

Schlick continued to rely on Kantian certainties. As noted above in passing, judgments of identity also play a central role in the verification of judgments about reality. Now Schlick spelt out a precondition which the latter had to satisfy to be counted even as candidate for knowledge: the terms of the judgment to be verified must be reduced to terms designating the given.

“A judgment has meaning only in connection with other judgments. In order for a proposition to have meaning, there must be given, in addition to the proposition itself, at least the definitions of the concepts occuring in it. In the case of a judgment about reality the definitions, in the final analysis, always go back in one way or another to what is intuitively given, and in the natural sciences and the social sciences and history, mostly to what is perceived through the senses. Thus every assertion about reality can be connected by a chain of judgments to immediately given facts in such a manner that it can be tested by these data. That is, matters can be so arranged that the presence or absence of specific data supplies the criterion for the truth or falsity of the judgment.” (Ibid., 162-163)

Note what Schlick did not stress, namely that what he earlier called “perceptual judgments [made] at the moment the perception occurs” now get assigned a very important role—one which stands in strong contrast to their dismissal as “superfluous” still in his habiltation dissertation.12 Given Schlick’s analysis of the condition of meaningfulness, these immediate perceptual judgments now had the task, as termini of the process of verification, of anchoring judgments of fact in experience. (That anchoring, however, remained fallible for the infallibility of these immediate perceptual judgments did not transfer to judgments about what was not given, but could only ground their proabability.)

Schlick’s modest ambition only to defend the possibility of knowing in principle the truth of conceptual judgments and the remaining rough probability of judgments about facts that transcend the given, surely counts as a laudable deflation of overreaching philosophical ambition. But this is not my concern here. It is rather that Schlick’s choice of words intimates that here we have the background to his theory of affirmations, if not its beginnings. Precisely of the judgments which constitute verifications (and which, when empirical facts are at issue, concern what is intuitively given), he says that they “affirm” (“konstatieren”) what they express, the identity of two judgments.13 It is tempting to call what was involved in the process of

12 It may be noted that Schlick did not spell out this consequence of his view either.13 In one of the quotations above: “affirming (konstatieren) identity” (1910-11/1979a, 101). In General Theory, speaking of the preconditions for knowledge, Schlick wrote: “we must be equipped with the ability to determine (konstatieren) whether ideas are the same or

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verification so as to allow an at least partial refutation of scepticism (namely of knowledge of conceptual truths) and to provide fallible support for empirical claims, “proto-affirmations”.14

It is to be noted also that in the General Theory Schlick still spoke of judgments and psychological capabilities: this was Schlick before the linguistic turn. The solution he had offered here for the problem of the ultimate ground of knowledge could no longer be upheld from the middle of the 1920s onwards, once he had, along with his assimilation of Wittgenstein’s philosophy, taken on board its linguistic turn as well. If he wanted to uphold it, Schlick’s anti-skeptical argumentation had to change as soon as he no longer spoke of judgments and their justification but of propositions and their truth-conditions. References to Kant’s transcendental apperception no longer sufficed to defend claims to knowledge even only in Schlick’s modest fashion.15

4.. Schlick and Wittgenstein: Interaction und Influence. To answer questions related to his theory of affirmations it is helpful to know about Schlick’s familiarity with Wittgenstein’s constantly developing philosophy.

Take the question in which extra-scientific language these affirmations are supposed to be formulated, a strictly phenomenalistic one or one speaking of experiences in our ordinary language. In September 1933 Schlick and Wittgenstein spent a week in Istria on the Adriatic coast in intensive philosophical discussions. By then, of course, Wittgenstein had long discarded his concern with the possibility (or even necessity) of a “primary” language and settled on our everyday language even for the description of visual space, as Schlick knew from earlier conversations.16 But there are also the manuscripts by Wittgenstein that Schlick reportedly had in his possession, as well as extracts and dictations.17 Fortunately (given the different.” And he noted, “that there is indeed no other way to establish (konstatieren) truth except through verification” (1918-25/1985, 101 and 165, orig. emphasis). To be sure, “konstatieren” and “Konstatierung” are established German words for “state what is the case” but it strikes me as significant that Schlick does not use them also in other contexts. 14 It may be wondered whether the switch in the content of these proto-affirmations between the habilitation dissertation, where they concerned “ideas” or concepts, and the conception of empirical verification in General Theory of Knowledge, where they concern sensory data or the phenomenal given, is significant. As far as I can see, the class of foundational judgments is widened, to be sure, but its nature of function is not essentially changed.15 Though Schlick never took the de-psychologization of epistemology as far as Carnap, he is sure to have noted that after the linguistic turn judgments were no longer bearers of knowledge. 16 See, e.g., McGuinness (1967/1979, 45 and 182).17 McGuinness reported that Wittgenstein asked Waismann to look for manuscripts of his at Schlick’s house after his death (Baker 2003, xxix) and that Waismann confirmed that none were missing from a set his sister Hermine held for him (McGuinness 2002, 272-274). The list of Wittgensteiniana in the Schlick-Nachlass in Iven (2010, 78–80) mentions only

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difficulty of dating them or their receipt by Schlick), for the present question we do not have to rely on them (even though they would confirm the conclusion).18 In light of his familiarity with the views of the “middle” Wittgenstein in September 1933 it seems reasonable to suppose that while Schlick’s affirmations speak of first-person experiences they are meant to be formulated in something like our ordinary language.19 (They were not part of a separate “primary” phenomenological language either of the kind which Carnap’s protocol statements had employed still in 1930 and which Wittgenstein had came to reject by then.)20

The comparison of Schlick’s remarks and formulations in the later part of the first half of the 1930s with materials deriving from Wittgenstein is instructive in other respects as well, but for this we also must not forget the fact that the transmission of ideas from Wittgenstein to Schlick at times required the intermediacy of Waismann, since Schlick was not always in Vienna when Wittgenstein was. This is of particular significance in the case

stenographed dictations or notes about and extracts from Wittgensteins writings. -- Of the archive numberings used below those starting with “D”, “MS” and “TS” are the ones introduced by von Wright (1967/1993) with reference to the Wittgenstein archive in Cambridge, those beginning with “Inv.-Nr.” the ones introduced by Reinhard Fabian with reference to the Schlick-Nachlass in Noord-Hollands Archief in Haarlem, and those beginning with “F” those referring to the Waismann-Nachlass in the Bodleian Library Oxford.18 There are two besides the “Blue Book” (see fn. 5 above) that are of particular interest to us. The first is the so-called “Diktat für Schlick” (“Dictation for Schlick”, D 302 and Inv.-Nr. 183, D.1 and D.3) which was dated to September 1933 by Iven (2010). The dating and the identity of the dictating author have been disputed—see Schulte (2011, 239) and Manninen (2011, 251). Oakes and Pichler (2013) provided a computational stylometric analysis suggesting Wittgenstein’s authorship which is compatible with both Iven’s thesis and Manninen’s thesis that the “Dictation“ was compiled by Waismann from Wittgenstein’s texts for a dictation to Schlick in 1935. The “Diktat” together with its translation was published in Baker, Voices, 1–83. The other is a typescript probably dating to 1934 which remained unpublished, Inv.-Nr. 184, D.5. It is nearly identical in text with that of Sections I–III of Part 1 of Philosophische Grammatik (1969/1974) and represents a further development of material from the so-called “Big Typescript” (TS 213), a compilation of his notes of the years 1929 to 1932 which Wittgenstein put together for the first time during the summer of 1933 and which provided the basis for further compilations. (On the history of the “Big Typescript”, see the Introduction by the editors of Wittgenstein 2005; on the history of Philosophische Grammatik siehe Kenny 1976. For more on Inv.-Nr. 184, D.5 see fn. 26 below.)19 The “Dictation for Schlick” warned against exaggerated conceptions of the privacy of mental states and the understanding of linguistic phenomena (see Wittgenstein and Waismann 2003, 27). In the same vein Inv.-Nr. 184, D.5, 27 (like Wittgenstein 1969/1974, 60) points not only to problems associated with ostensive definitions but also appeals exclusively to ordinary language for examples to hang philosophical reflections on and again rejected earlier attempts at an analysis that aimed to reach a deeper level of a “primary” language. 20 See, e.g., Carnap (1930/1959, 143-144). McGuinness (1967/1979, 45, fn. 8) suggests that Wittgenstein’s rejection was not completed without hesitation. It is not inconceivable that Schlick should have thought of the identity of statements which constitute verification as statements in such a “primary” language still in his own “Turning Point” of 1930.

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of the dictations given by Wittgenstein to Waismann in Dezember 1931 and January 1932 when Schlick was a visiting professor in California. It was in these dictations that Wittgenstein made explicit the then newly reached standpoint of his from which he condemned Waismann’s so-called “Theses” as a “dogmatic account” and “rehash” of his Tractatus.21 Until then Waismann had taken the “Theses” to be an authorised summary of Wittgenstein’s own recent understanding of his book, enriched by remarks on the the nature of hypotheses and ostensive definitions, and had presented them as such for discussion in the wider Vienna Circle at several of their meetings. Wittgenstein found his dictations important enough to ask Schlick by letter in the following spring whether Waismann had indeed passed them on—and they are revealing indeed.22

The development of Wittgenstein’s thought resists easy summaries but for present purposes this may suffice. Starting from the problem of color exclusion (no point can have more that one color) Wittgenstein distanced himself from the position adopted in the Tractatus according to which the logical form that constitutes the meaning of a proposition is determined solely by its reduction to the elementary propositions of which it is a truth function. Instead he first also recognized as semantically significant the systematic relations between propositions of the same logical type—only to then turn away from depth analyses altogether.

This turn of his thought Wittgenstein remarked on in conversation with Waismann on 9 December 1931 where he expressed the view now overcome as one where one makes presuppositions about what one does not know as yet (say about the form of the elementary sentences). The point was formulated more succinctly in the course of the dictations for Schlick during the following weeks.

“My error was a wrong conception of analysis, namely the conception that something is hidden in a proposition, a structure that has to be drawn into the light. I had the conception—which is produced by our misleading use of language—that the sense of an expression is hidden, as it were, behind the expression. I shall explain this by means of a simile. Let us imagine cubes, prisms, and pyramids made of glass as being completely invisible in space. Only one surface of each oprism, for example a square, and the base of each pyramid are supposed to be coloured. We will then, for instance, only see squares in space. However, we are unable to join together these plane figures arbitrarily because the bodies that behind the surfaces prevent this. The law

21 See McGuinness (1967/1979, 182 and 184) and compare the “Theses” (ibid., 233-261).22 They have been found by Juha Manninen among the texts published as “Notizbuch 1” (Baker 2003, 84-275). See Manninen (2011, 254) for the narrative of discovery and a list of the passages in this “Notebook I” which stem from these dictations by Wittgenstein. All the following quotations from “Notebook I” in Baker (2003) are taken from these passages identified by Manninen.

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according to which the surfaces can be fitted together is determined by the invisible bodies whose surfaces are the squares.”23

The change away from this conception was far more radical than Waismann had realized up to then and represented a sharp break with what he presumed was Wittgenstein’s understanding of philosophy (and what had been Wittgenstein’s previous philosophy). Waismann was right to indicate in response that it was no longer the task of the logical analysis of language to “describe the most general aspects of reality, those which are common to language and reality and make the expression of thoughts possible” (in McGuinness 1967/1979, 184). But what was involved was not only a change in the point of philosophical analysis but also a change in the nature of its inquiry. Again the dictation for Schlick is clearer than the record of the conversation with Waismann:

“In philosophy we do not want to give explanations—precisely because no explanation can satisfy us. What we want to give and what we must give is, in the end, only a description. Our method is the method of perspicuous representation.”24

The kind of explanation rejected here is causal explanation. Wittgenstein was adamant that philosophical explanation operated on a different, normative level.

As we shall see, it took some time for Schlick too to realize the radical nature of Wittgenstein’s methodological turn. (He can be assumed to have received a copy of Wittgenstein’s dictations by the Spring of 1932 at the latest.) For instance, Schlick’s London lectures in the Fall of 1932 are still strongly marked by the impression left on him by Wittgenstein’s ultimately futile attempts to devise a better conception of logical form. That “grammatical investigations” do not reach into hidden depths but instead aim for the “perspicuous representation” of that which is evident in the usage of ordinary language cannot yet be gleaned from “Form und Content”, even though the concept of “grammar” is already used there. However, any uncertainty about the new methodology—and the results it yielded—that Schlick may have felt was dispelled after the discussions with Wittgenstein in September 1933. So the value of these discussions for Schlick, in any case, was that of a stock-taking, of the clarification of the changes underway, not of a radical new insight. Even so, it was only afterwards, that Schlick felt free to embrace the epistemic folkways of ordinary language. (But Wittgenstein too must have felt something was gained for that Fall he started dictating the “Blue Book” to students in Cambridge.)

23 F37, “Notebook I”, in Baker (2003, 133, orig. emphasis)24 F 35, “Notebook I”, in Baker (2003, 121, orig. emphasis).

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Months later Schlick is likely to have found his own application of this new method to epistemology confirmed, for it is highly notable that Schlick wrote to Carnap in May of 1934 (while “Foundations” was in press):

“Wittg[enstein’]s own ms., of which I have large parts for safe keeping, is a true work of genius. It really clears up the philosophical problems without any formal preliminaries or special technical auxiliaries.”25

Now Schlick no longer was in any doubt about the radical changes Wittgenstein had wrought: he evidently referred to the “Big Typescript”. Which parts he had for keeping remains so far unknown, except for the further revised excerpt Inv.-Nr. 184, D.5, which he is likely to have received that year.26 However, this typescript—which I take to be identical with one

25 “Wittg[enstein]s eigenes MS, von dem ich einen großen Teil in Verwahrung habe, ist höchst genial; es räumt wirklich mit den philosophischen Problemen auf ohne jede formale Vorbereitung und besonderen Hilfsmitteln.” Moritz Schlick to Rudolf Carnap, 10 May 1934 (ASP RC 029-28-17).26 Concerning Inv.-Nr. 184, D.5, the following is to be noted. First, that it is not identical with MS 140 (the so-called “Grosses Format”), since it also features the content of §§ 14–22 und 41–42 (up to “Wie verhält es sich …”) of Philosophische Grammatik which is missing in MS 140. Second, that it is not identical with a continual excerpt from the second part of MS 114, since it follows (apart from smaller deviations) the order of Philosophische Grammatik §§ 1–42. Third, that it also is not identical with what one would obtain if one followed the instructions for revision to be found in the second part of MS 114, since it does not follow what Anthony Kenny has identified as a misleading instruction (§ 13 is retained), shows an omission in § 19, adds an additional first sentence in § 14, and contains three short additional paragraphs in § 42. What all this strongly suggests is that Inv.-Nr. 184, D.5 is a typescript closely related to a working out of Wittgenstein’s instructions for revision of the second part of MS 114 which served Rush Rhees as the (as Kenny also remarks, not always faithfully followed) blueprint for his production of Philosophische Grammatik. Since Inv.-Nr. 184, D.5 uses contents of both the second part of MS 114 and of MS 140 and since the latter dates to 1934, this suggests therefore that it is a typescript Wittgenstein had made in 1934 and passed on to Schlick. Finally, note first that in the Rose Rand-Nachlass there exists a typed copy (ASP RR 11-7-2), which is identical in content to Inv.-Nr. 184, D.5 except for some very small changes or typographical errors, and that she also possessed, as one referee informed me, a shorthand manuscript of the dictation. Second, that Inv.-Nr. 184, D.5 also fits Baker’s description (“based on the ‘Zweite Umarbeitung’ of the ‘Big Typescript’”, i.e. MS 140 ) of a typescript “Wi:MS” found in Waismann’s papers (2003, xxvii fn. 3).

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called “Mulder V”27—and Waismann’s notes already allow us to discern the outlines of Schlick’s reception.28

Before I turn to that and the significance Wittgenstein’s remarks possess for Schlick’s concern with skepticism, I must note that for the interpretation to be outlined it is not claimed that Wittgenstein would have approved of Schlick’s response as here interpreted. Despite far-reaching agreements between them they nevertheless pursued different projects that fitted with their different intellectual histories. If then Schlick is here interpreted through the spectacles of certain “Wittgensteinianisms”, it is because Schlick was much concerned to integrate these into his own thinking. That in doing so he may have contradicted other ideas of Wittgenstein’s—consciously or not—need not be denied. For instance, there are Wittgenstein’s remarks in the Blue Book and elsewhere on so-called “Äusserungen” or “avowals”, self-ascriptions of experiences and mental states, concerning which he denied that they represented genuine propositions and therefore that they could express knowledge. I should stress therefore that the interpretation to be considered is not meant to portray Schlick as a faithful Wittgensteinian.29

5.. Schlick’s Development in Vienna: Two Turning Points. So how did the “old” problem present itself in the new Wittgensteinian context? To see this aright we must note that Wittgenstein occasioned not only one but two “turning points” in Schlick’s philosophy during his Vienna period. There is of course the general change that there was no more talk of judgments and that the reference to Kant’s transcendental apperception fell away, but much more was involved than this.30 27 Concerning the relation of Inv.-Nr. 184, D.5 to Mulder V the following is to be noted. Inv.-Nr. 184, D.5 has the same number of pages as those reported for D 308 which was described by von Wright as as “Dictation to Schlick. The so-called Mulder V. 57 pp” (1969/1992, 492), but about which he later remarked skeptically (1997, 24) that he did not know its whereabouts. Michael Nedo meanwhile simply claimed the “practical identity” of sections I–III of Philosophische Grammatik for “a text which Wittgenstein presumably dictated to Moritz Schlick in the year 1934, the so-called ‘Mulder V’” (2000, ix). Given the convergence of their descriptions I take as my working hypothesis that Inv.-Nr. 184, D.5 is identical with Mulder V (D 308), but nothing much hangs on this and I make no assumptions about how it came to Schlick. Manninen suggests that the typescript was produced by Waismann (2011, 262).28 Given the dispute of the 1933 dating for the “Dictation to Schlick” my narrative of Schlick’s reception of the middle Wittgenstein will not rely on it essentially; and given the unclarity about the date of his receipt of Inv.-Nr. 184, D.5, I will also call on it only when the entirety of Schlick’s affirmations-conception is at issue and not just “Foundations”.29 Wittgenstein’s arguments concerning first-person psychological sentences are explicated in detail in Malcolm (1986, ch. 8) and critically discussed in Bakhurst (2001). Friedl (2013, 209–212) rightly notes this difference between Schlick’s theory of affirmations and Wittgenstein’s developing conception of language. 30 One may also compare the replacement, in later lectures, of the earlier appeal to Kant’s transcendental apperception in his anti-skeptical argumentation by the statement that without understanding of meaning all questions of knowledge become void (1938/1979,

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The first turning point consisted of the epistemological model of General Theory being adjusted to that of the Tractatus.31 Consider Schlick’s suitably titled opening essay in Erkenntnis, “The Turning Point in Philosophy” of 1930. Following two paragraphs that declared that thanks to the correct understanding of the nature of logic and logical form due to the efforts of Frege, Russell and—decisively so—Wittgenstein, it became possible to “dispose of the traditional problems of the ‘theory of knowledge’”, Schlick wrote:

“Wherever a meaningful problem presents itself, it is always possible, in theory, to indicate the road leading to its solution, for it turns out that the indication of this road is basically equivalent to stating its meaning … The act of verification, in which the road to solution finally terminates, is always of the same kind: it is the occurrence of a particular state-of-affairs, ascertained (konstatiert) by observation and immediate experience.” (1930/1979, 156-157)

Schlick here suggested a solution of the old problem of knowledge—“questions regarding the ‘validity and limits of knowledge’”—that evidently was indebted to the logical atomism of the Tractatus. The convergence of meaning and method of verification which Schlick invoked demanded not only the reduction of every meaningful proposition to its constitutive elementary propositions, but also the communion of structure (logical form) between the elementary propositions and the elementary facts they picture. Ascertaining (“konstatieren”) such a communion of structure represents the final criterion of truth. In the new Tractarian context, of course, the very process of ascertaining truth also had to be reconceived: verification no longer terminated in the metalinguistic identity judgments of old but in instances in which the correspondence of elementary sentences and elementary facts showed itself to the speaker or thinker. Now how far Schlick already saw himself struggling again with scepticism in “Turning Point” is unclear, but it seems that we may locate his “proto-theory” of affirmations here: the possibility which his General Theory darkly hinted at was beginning to be realized. The grounding provided by these verifying sentences secured at least the certainty of philosophical knowledge conceived as meaning determination (1930/1979, 159).

So far, so good—but trouble was brewing in this verificationist paradise. As noted, the changes that Wittgenstein himself was making to the conceptions of the Tractatus were by no means restricted to adding ideas concerning 350).31 To be more precise: Schlick’s essay “Erleben, Erkennen, Metaphysik” (“Experience, Cognition and Metaphysics”, 1926), which documents for the first time his new way of thinking, builds on the significant correspondences that obtain between, on the one hand, his General Theory and, on the other, his creative amalgamation of Wittgenstein’s Tactatus and Carnap’s Der logischen Aufbau der Welt which was nearing completion (which amalgamation was later styled as the standard conception of Logical Positivism: see Blumberg and Feigl, 1931, 285–288 and 292-293).

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hypotheses (propositions which were not truth-functions of elementary propositions) and ostensive definitions, but included the denial of the logical independence of elementary propositions from each other. This meant that the issue of logical form—its nature and our knowledge of it—was opened anew for the specification of meaning demanded a “comprehensive syntax” that pays attention to the “inner connexion between sentences”, as Wittgenstein had put it darkly when he communicated this point already in January 1930.32 It also demanded a revision of the approach to the traditional problem of the theory of knowledge that was given expression in “Turning Point”.33

Schlick accordingly tried to accommodate the view that logical form not only represents the result of a reductive analysis of individual propositions, but also reflects the systematic connection of propositions with others of its type. A first attempt in this direction is discernible in the first of the London lectures “Form and Content” of the Fall of 1932, called “The Validity of Knowledge”.

“Evidently, it belongs to the intrinsic nature of our green that it occupies a certain position in a range of colours and a scale of brightness, and this position is determined by relations of similarity and dissimilarity to the other elements (shades) of the whole system. … In this way every quality (for instance, qualities of sensation; sound, smell, heat etc. as well as colour) is interconnected with all others by internal relations which determine its place in the system of qualities. It is nothing but this circumstance which I mean to indicate by saying that the quality has a certain definite logical structure.” (1938/1979, 293-294)34

This is a different concept of structure than the reductive one which Schlick had employed still in “Turning Point”, but the latter one also still remained in place. In the third lecture we hear:

“The logical structure of the proposition has, of course, very little to do with the linguistic grammatical structure of the sentence and is ever so much more complicated. In order to get at it we must imagine all the words of the sentence to be replaced by their definitions, the terms occurring in the definitions must be replaced by subdefinitions, and so on, until we reach the boundary of ordinary language where it ends in gestures or prescriptions to perform certain acts. In some cases, where no explicit definition of a term is possible, the whole sentence will have to be transformed into a new shape, and the actual procedure of

32 See McGuinness (1967/1979, 73-74). 33 This point was amplified further by comments in Wittgenstein’s dictation to Waismann for Schlick (F41, “Notebook 1”, Baker 2003, 244-246).34 This is the later published last revision of 1934, but comparison with the 1932 original shows that no content changed in the passage at hand; see Schlick (2013, 179-180).

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finding its meaning might become inextricably complicated, if in psychological reality it were not shortened and simplified by habit and instinct.” (Ibid., 270)

Here Schlick continued to conceive of verification as involving a depth analysis that must reach the “boundary of ordinary language” by means of the reductive analysis of logical form. Overall Schlick’s concept of structure had become ambiguous in the attempt to comprehend both the reductive and the systematic-complementary version of logical form. More generally, the revision of the concept of logical form that Schlick attempted in his London lectures ended in failure, for it forced him to deny that we ever were in a position to speak of the qualitative contents of our experience, let alone communicate those to others. His London lectures may be thought of as his first attempt to come to terms with Wittgenstein’s post-Tractarian changes, but it was to require yet another attempt to solve the old problem in a new fashion.35

Note also that as so far described verification was still a matter of witnessing, of making contact with reality by means of elementary propositions. This shows that at this point in time Schlick had not yet followed Wittgenstein with respect to one of the most radical of the changes he had initiated—namely that of giving up talking of “making contact with reality” (“Berührung der Wirklichkeit”). In Waismann’s “Notebook I” we read:

“If I explain the sense of a proposition by means of another proposition, how do I know what these new propositions mean? Language must surely at some point make contact with reality.

This question is grounded in a misunderstanding. … Through the specification of the verification, I cannot connect the

language with the world. I cannot do that at all. There is no intermediate link between language and reality. I can only remind myself of the use of the language.”36

So “Form and Content” did not keep up with all of Wittgenstein’s changes. Certain of the ideas that Wittgenstein wanted to communicate to Schlick clearly did reach him—like the idea that the Tractarian difference between “saying” and “showing” is identical with the difference “between what language expresses and what grammar says”, that is, between external and “internal relations”37—but apparently not yet all of them. Here then we stand on the threshold of Schlick’s second turning point: his own 35 It fits that between his London lectures “Form and Content” of Fall 1932 and his “On the Foundation of Knowledge” of Spring 1934 Schlick did not only publish nothing substantial but by the end of that period also had abandoned his plan to publish the London lectures as a book; see Friedl (2013, 169) und Friedl and Rutte (2013, 150).36 F 40 in “Notebook 1”, in Baker (2003, 117).37 F 29 in “Notebook 1”, in Baker (2003, 130–132); compare the text of the first lecture of “Form and Content” in both versions (1938/1979b, 294-295) and (2013, 179–181).

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recapitulation of Wittgenstein’s revision of his conception of philosophical insight as no longer promoted by an analysis of language that searches hidden depths, but one that reflects actual usage. Once this point had become fully clear to Schlick he was able to draw the consequence: what he was to call “the unshakable points of contact between knowledge and reality” (1934/1979, 387) were determined and identified no longer by the excavation of hidden structures but by the “perspicuous representation” of that which is familiar to us all along, our use of ordinary language.38

This brings us to his later theory of affirmations which Schlick outlined for the first time in lectures during the winter semester 1933/34 and then made the topic of “On the Foundation of Knowledge”. Of considerable less scope than his London lectures, this was meant as an occasional piece—“a gentle warning” as he said in retrospect (1935a/1979, 400). Importantly, however, it shows that by this time he had assimilated Wittgenstein’s rejection of depth analysis as he had not done previously. To see this, consider only that—as we noted above (§2)—affirmations stood in at best indeterminate logical relations, if any, to the observation language of science. But even “Foundations” does not yet represent a final version of the theory, for only his subsequent publications on the topic explicitly appeal to the new understanding of language and its workings that he had begun to assimilate from Wittgenstein. These contributions place Wittgenstein’s concept of grammar in central place in order to address some evident difficulties. As we saw earlier, affirmations, statements about present experiences received a distinguishing characterization through grammatical rules that only applied to them. What is particularly significant for our purposes is that in Schlick’s last contributions on the matter—his Erkenntnis essay is not at all clear in this respect—the key point of realizing that the correspondence or coordination of proposition and reality obtains is no longer presented in the guise of an at best poetically describable experience of identity of logical form, but by the fact that the grammatical rules that hold for the expressions involved have indeed been followed.39 This marked difference clearly attests to Schlick’s ongoing assimilation of Wittgenstein’s ideas.

6.. Affirmations against Skepticism. We recall: already the early Schlick recognized a factor in the process of verification that allowed him an at least partial rejection of skepticism. After the linguistic turn the identity judgments basic to his early conception of verification were transformed first into a simple awareness of the isomorphism of the logical form of sentences involved in verification. According to this conception what was needed was not a transcendental analysis of consciousness but a depth analysis of language. The identity was conceived in structural terms 38 That Schlick gave a highly non-technical exposition and evocative, even poetical description of what affirmations do for us was, accordingly, far from accidental.39 Talk of “correspondence” is justified insofar as Schlick spoke freely of “comparisons” between statements and facts in (1935a), his reply to Hempel’s objections (1935) to his own (1934).

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as that of the underlying logical form of both representation and the represented. Yet the failure of the structuralist model of language understanding called for another reconceptualization. It was in Wittgenstein’s concept of the logical grammar of ordinary language that Schlick thought he could find the resources needed to revise his model of knowledge as required—and more convincingly than before. Schlick now sought the anti-skeptical solution in the correct embedding in ordinary language of propositions characteristic of processes of human knowledge acquisition. (Schlick also dropped the idea of an individual point of contact between knowledge and reality together with the idea that something hidden had to be uncovered: both had been explicitly problematized by Wittgenstein.)

Circumstantially, what is significant is that Schlick’s new conception of affirmations was first presented, as noted, in a rudimentary form in lectures during the winter semester of the academic year 1933/34—after his working holiday with Wittgenstein at the Adriatic coast in September. Doctrinally what is of overarching importance is Wittgenstein’s new understanding of language and its workings which contrasts with that of the Tractatus.40 It is not unreasonable to assume that the topic which occupies the beginning of the “Blue Book” which Wittgenstein began to dictate back in Cambridge not long afterwards also was a topic for their discussions in Istria: the nature of linguistic meaning and the emerging conception of use.41 That these matters concerned Wittgenstein would not have been news to Schlick who will have read in Wittgenstein’s dictations to Waismann: “Anyone who explains a sign describes its use.”42 Let us consider this further.

Explaining the use of a sign, Wittgenstein insisted, was not a matter of setting out causal connections.

“The question: what is the execution of an order? is a question about the sense and its answer a grammatical explanation, not the statement of what is going to happen. A question about the sense of a proposition is answered by a linguistic agreement and was therefore also a question about such an agreement. It is not answered by an empirical fact, nor was it therefore the question about such an empirical fact. It is just the same thing with the meaning of a word. The answer to this question is a description of the use of language in

40 If it weren’t for the dating problems, I could quote here the beginning of his “Dictation to Schlick”: “One could say: to understand a word means to know how to use it. … The ability to use a word is not a state of consciousness that accompanies the use of the word. (This is a grammatical remark.)” (D 302, “Dictation to Schlick”, in Baker 2003, 3) 41 “If we had to name anything which is the life of the sign, we should have to say it was its use. … The mistake we are liable to make could be expressed thus: We are looking for the use of the sign, but we look for it as though it were an object co-existing with the sign. (One of the reasons for this mstake is again that we are looking for a ‘thing corresponding to a substantive’.)” Wittgenstein (1958, 4-5)42 F34, “Notebook 1”, in Baker (2003, 103, emphasis added)

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the manner of an agreement even before this language has been used yet. Hence a question about meaning is not a question about empirical facts, but a question about an agreement.”43

The agreements in question are condified in rules.

“The signs of a language are used according to certain rules. What are the rules by which a game is played? … a rule of a game is not a hypothesis which is satisfied by the actions of the player, but it is the rule which the player gives as an answer if asked for a rule.”44

Language use in its broadest sense was spelt out in terms of rules—including now even the determination of whether a sentence “is an elementary proposition or not”.45 Thus arise the very questions which occupied Wittgenstein in varied ways throughout the early 1930s: what is a rule and what is it to intend a certain meaning and what is it to understand a word or sentence?

The answer given here was that the meaning of a word or a sentence and the rules governing it are not contained in a “meaning body”:

“I thought that a word had, as it were, a ‘body of meaning’ behind it, and this body of meaning was to be described by the grammatical rules that hold true for the word. The grammatical rules would then be, as it were, an unfolding of the nature of the body of meaning. … We do not extract rules from meanings, as if meanings stood behind words like objects in space. ”46

Elsewhere but not in these dictations Wittgenstein went on to argue extensively that following rules and meaning something with a word is not a state of consciousness; here he offered this:

“We state a rule and do nothing else. We provide a perspicuous representation of a system of rules, namely, of a system which does exclude our employing all those propositions which we have always wanted to exclude, which have always aroused suspicion in us. That one decides to drop them throws light on just what attitude one had towards them.”47

Clearly many questions are left open here, but that a seismic shift in Wittgenstein’s conception of language was underway was plain. And there can be no doubt that the new conception was further discussed in September 1933. That linguistic meaning is determined by the use of

43 F33, “Notebook 1”, in Baker (2003, 97).44 F34, “Notebook 1”, in Baker (2003, 103).45 F41, “Notebook 1”, in Baker (2003, 247).46 F33, “Notebook 1”, in Baker (2003, 133-135, orig. emphasis)47 F 35, “Notebook I”, in Baker (2003, 125)

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linguistic signs (and not the other way around) is a doctrine generally associated with the later Wittgenstein, but Schlick and Waismann were taught it in person by the middle Wittgenstein still before he first presented it in lectures and dictations for his Cambridge students.

As already noted, Schlick’s mature conception of affirmations looks to the cognitive—better, lest it be misunderstood: linguistic—process, to what we do in ordinary practice, and places much less emphasis on the depth analysis of logical form than previously.48 Affirmations were characterized, we saw, by special rules.49 So in writing “Foundations” Schlick took on board Wittgenstein’s message that solutions to philosophical problems must not appeal to anything hidden. In so far as the traditional problems of epistemology were to be dealt with in a new way, they were dealt with in terms of our ordinary linguistic practice, albeit one that was reconfigured by a new understanding of how we relate to—better: operate in—the world with language.

To be sure, one may wonder what Wittgenstein’s topics in philosophy of language had to do with the epistemological ones to which Schlick’s theory of affirmations was dedicated. The answer is: a surprisingly large amount! Many of the applications of his new ideas that Wittgenstein explored at the time (for instance, in the “Big Typescript”) concern the language of mental phenomena and many of these terms pertain to cognition. Wittgenstein’s remarks on the topic of how language is understood therefore can be transferred directly to the issue of how we know things. Schlick can be assumed to have known this. To be assured of this we not even speculate as to when he received which parts of the “Big Typescript”, say, for safe keeping: all we need to remember are the remarks Wittgenstein made to Waismann when he showed him parts thereof on 21 September 1931 (remarks which surely were reported to Schlick):

“In this work I again and again concern myself with the question, What does it mean to understand a proposition? This is connected with the general question of what it is what people call intention, to mean, meaning. Nowadays the ordinary view is, isn’t it, that understanding is a psychological process that takes place ‘inside of me’. So I ask, Is this understanding a process that accompanies a proposition—i.e. a spoken or written proposition? . . . I now believe that understanding is not a particular psychological process at all that is there in addition, supplementary to the perception of a

48 It may be wondered whether reductive meaning analysis does not continue to furnish the backdrop for the theory by providing the affirmations in the first place, so Schlick’s assimilation of Wittgenstein’s insights would be less than complete. Yet given that Schlick declined to specify the precise logical relation his affirmations stand not only to the scientific but also the ordinary language, this not clear. 49 They were the only class of synthetic sentences that worked like analytic ones: to understand them was to recognise their truth; see Schlick (1934/1979, 385).

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propositional picture. . . I understand a proposition by applying it. Understanding is thus not a particular process; it is operating with a proposition. The point of a proposition is that we should operate with it. . . . The view I wish to argue against in this context is that understanding is a state inside me, like, for instance, toothache.” (McGuinness 1967/1979, 167)50

If understanding is not a state in the disputed sense, then knowing isn’t one either. This much Schlick surely was able to conclude. Further deepening his understanding in discussion with Wittgenstein he arrived at a conception of affirmations as not reporting on such inner states of knowing that cannot be doubted but as expressing a subject’s competence with regard to basic cognitive operations. When Schlick received his copy of “Mulder V” he no doubt felt vindicated. There we can read:

“Well, ‘understanding’ is not the name of a single process accompanying reading or hearing, but of more or less interrelated processes against a background, or in a context, of facts of a particular kind, viz. the actual use of a learnt language or languages.”51

Wittgenstein’s argumentation here may be understood as a generalization and deepening of the argument that prompted him to drop his earlier view of philosophical method as analysis in the sense of an uncovering of hidden structures. Now Wittgenstein was led to a highly persuasive presentation of his concept of family resemblance:

“What a concept-word indicates is certainly a kinship between objects, but this kinship need not be the sharing of a common property or a constituent. It may connect the objects like links in a chain, so that one is linked to another by intermediary links. Two neighbouring members may have common features and be similar to each other, while distant ones belong to the same family without any longer having anything in common. Indeed even if a feature is common to all members of the family it need not be that feature that defines the concept.

The relationship between the members of a concept may be set up by the sharing of features which show up in the family of the concept, crossing and overlapping in very complicated ways.”52

Description in place of analysis is the motto here as well: to be precise, family resemblances took the place of necessary and sufficient conditions. It is also interesting that Wittgenstein continued, in response to the imagined counter that, if matters were so, then anything could be

50 I have amended the translation by restoring “. . ., der sich ‘in mir’ abspielt. Ich frage nun: Ist das Verstehen ein Prozess, . . . “ to the third and fourth sentences of the quotation.51 Inv.-Nr. 184, D.5, 45, orig. emphasis; text identical with Wittgenstein (1969a/1974, 74)52 Inv.-Nr. 184, D.5, 45-46, orig. emphasis; text identical with Wittgenstein (1969a/1974, 74-75).

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connected with anything else, and that no concept, even that of knowledge, could be properly delimited:

“To this I have to say that for the most part it isn’t in fact bounded and the way to specify it is perhaps: ‘by “knowledge” we mean these processes, and these, and similar ones’. And instead of ‘and similar ones’ I might have said ‘and others akin to these in many ways’.”53

So the concept of knowledge and our cognitive practice generally also fall under the purview of Wittgenstein’s new perspective. There need not be one thing underlying true knowledge claims, but making one must be suitably related to other ones. Note that this perspective introduces what in today’s parlance are considered elements of externalism and contextualism. Again, this is not to say that Wittgenstein developed these points systematically in their epistemological dimension at the time; after all, he did not sustainedly engage in these issues until more than a decade later in the reflections on Moore that were published posthumously as On Certainty. My claim is rather that Wittgenstein’s remarks are relevant not only for theoreticians of mind and language, but also for epistemologists and that Schlick perceived them so.

It is especially notable that in the run-up to this argument and its summary Wittgenstein also remarked:

“I hear a word and someone asks me: ‘did you understand it?’ and I reply truly ‘yes’. What happened when I understood? How was the understanding different from what happens when I don’t understand a word? – Suppose the word was ‘tree’. If I am to say truly that I understood it, must the image of a tree have come before my mind? No; nor must any other image. All I can say is that when I was asked ‘do you understand the word ‘tree’?’ I’d have answered ‘yes’ unthinkingly (unbedenklich) and without lying.”54

The “unthinkingness” (“Unbedenklichkeit”) Wittgenstein noted here must not be equated with thoughtlessness or carelessness: it is not inattention that is marked by the term but instead the unreflective ease of competence: here it means not answering unduly without a thought but answering without undue hesitation. It is this second sense of “unthinkingness” in giving a truthful answer to the question whether I understand a linguistic expression that also describes the attitude of someone making an affirmation which Schlick described in “Sur les constatations”. In both cases further probing by the questioner would only be met by puzzlement on the part of the respondent. Such “unthinking” use is valid as long as it is indeed correct and in agreement with accepted usage. This conception of what linguistic understanding amounts to allows for doubts about its

53 Inv.-Nr. 184, D.5, 46, orig. emphasis; text identical with Wittgenstein (1969a/1974, 75).54 Inv.-Nr. 184, D.5, 43; text identical with Wittgenstein (1969a/1974, 73).

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aptness in particular cases, but the possibility of understanding is not called into question as problematic in principle and as such. An “unthinking” use can very well be and often is a legitimate use of a word.

As may be gathered by now, I see Schlick fashioning his response to the problem of misremembering the meaning of a term used in an affirmation along similar lines. Just as a claim to knowledge of language is not to be grounded in knowledge of the necessary and sufficient conditions of the reference and satisfaction relations of the expressions of a language, but only in demonstrable competence of use, so anti-sceptical claims to knowledge of the world can only be grounded—to the extent that they can be grounded—in the correct use of affirmations. To be sure, there is no guarantee that one does use the relevant terms and predicates correctly and to respond, as Schlick did, by saying that it does not matter if I do not as long as I as think I am using them correctly does not fully do justice to the problem. What he should and could have said is that individual cases of mistaken confidence do little to undermine the basic reasoning at issue here. As we saw, Schlick’s pre-Vienna Circle refutation of skepticism toward conceptual truths was only an in-principle one, based on the transcendental unity of apperception. Unlike his earlier argument, his theory of affirmations extends its anti-skeptical reach to a subclass of empirical claims and, equally importantly, bases it on decidedly this-worldy linguistic competence conceived as correct usage. But its anti-skeptical force is likewise only an in-principle one, so Schlick can again reject as unwarranted demands for a stronger response to skepticism and accept that affirmations do not logically guarantee their truth (if they are meant—as surely they are—to be equivocal with ordinary usage). The certainty they afforded was, as Schlick conceded, a subjective, psychological one.

Yet Schlick was able to go still further—with Wittgenstein. The supposedly intrinsic privacy of knowledge and the finality of a criterion of truth, for instance, once thought of essential to the phenomena of knowledge and truth themselves, can now be regarded as “merely” grammatical rules that hold for our language. For a view like this Schlick could call on the “Diktat”

“We are inclined to say: only he himself can know whether he understands something. This way of speaking evidently corresponds to this other one: only he can know whether he has a toothache. But this possibility and impossibility of which we here speak is a logical, not an empirical one. That means that the proposition ‘only he can know …’ or ‘he cannot be mistaken in thinking that he understands it’ is to be understood as a characterization of the grammar of the word ‘understand’. … here we are free to admit a definitive criterion or to play a grammatical game in which no such criterion is provided for. With the words ‘provided for’ I want to emphasize that the absence of a

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definite criterion is not an experiential fact, and that it corresponds exactly to the absence of a king in draughts.”55

“Mulder V” also states clearly:

“that the word ’know’ doesn’t denote a state of consciousness. That is: the grammar of the word ‘know’ isn’t the grammar of a ‘state of consciousness’, but something different. And there is only one way to learn it: to watch how the word is used in practice.”56

With essence questions turned into questions of grammar and issues of knowledge and justification beginning to be contextualized and externalized, Schlick was able to confront the central problem of his theory of affirmations—to have gained a final criterion of truth for the price of its irrelevance for the everyday and for science—in a fashion that was previously inconceivable.57 Schlick was able to declare it to be a problem only for an analyst who disregards the unthinkingly and rightly presupposed embedding of our statements into the ordinary language we all speak. Schlick, in other words, took himself to have at least taken steps to dissolve the problem of skepticism by breaking the spell that a wrong conception of knowledge and justification held us under.

The philosophical attitude that Wittgenstein sought to promote was clearly not one according to which the problem at hand, be it concerned with the understanding of language or our ability to know in general, became a critical one. “We are interested in language as a procedure according to explicit rules, because philosophical problems are misunderstandings which must be removed by clarification of the rules according to which we are inclined to use words.”58 Someone who followed Wittgenstein up to this point does not have to worry about the problem that affirmations pose. And evidently Schlick did not do so. The “old” problem—“the wish for absolute certainty of knowledge”, the search “for an unshakable foundation, immune from all doubt and forming the firm basis on which the tottering edifice of our knowledge is reared”—was now dissolved “grammatically”. There was no deeper ground to provide security for affirmations than meeting the condition to employ words according to the grammatical rules that hold for them, nor a longer-lasting foundation than the occasions of their use. If this condition was met, all doubt is idle. What I called the “central problem” of his theory of affirmations was a problem only for a conception of knowledge

55 D 302, “Dictation for Schlick”, in Baker (2003, 25-27).56 Inv.-Nr. 184, D.5, 41; text identical with Wittgenstein (1969a/1974, 71).57 In previous discussions of the theory of affirmations—e.g. in (2007, Ch. 10)—I dismissed the possibility of an externalist reading of it on account of its seeming anachronism. This was justified in so far as I did not there consider Wittgenstein’s then as yet unpublished ideas. The present essay may therefore be considered also as an investigation of this “loophole” and Schlick’s possible escape. 58 Inv.Nr. 185, D5, 37; text identical with Wittgenstein (1969a/1974, 68) .

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and justification that he rejected as unduly intellectualist—as we would say nowadays: “too internalist”.

It was in precisely this sense—“there is no deeper ground…”—that Schlick is likely to have understood the following passage towards the end of “Diktat”:

“[W]e are accustomed to calm our mental disquiets by tracing certain propositions back to more fundamental ones. But if our disquiet arises from some unclarity about grammatical relations in some domain of language, we will then, on the one hand, be tempted by force of habit to apply here the useless remedy of tracing things back to more fundamental propositions, and, on the other, we feel sure that we have use for a foundation in the more homely (“hausbacken”) sense of the term.”59

That Wittgenstein did not only chastize the philosophical tradition here but also his earlier self should be readily apparent by now, likewise that Schlick was able to recapitulate both his criticism and self-criticism—and that he now was also able to draw the appropriate consequences. After all, as we saw, his affirmations are no “homely” foundations of old!

7.. Conclusion. According to the interpretation presented here, Schlick’s theory of affirmations offers a reconceptualization of his youthful in-principle argument against skepticism by way of a Wittgenstein-inspired a grammatical dissolution of the old problem of the foundation of knowledge. Does this mean that Schlick turned his back on anti-metaphysical philosophy of science of the Vienna Circle? Such a description would be too extreme. To begin with, his anti-scepticism all along possessed a certain quasi-naturalistic element in presupposing as given a certain psychological capacity the successful deployment of which would at least allow the partial refutation of skepticism. But Schlick did put increasing distance between his own philosophy and that of his colleagues on the so-called “left” or “unified science” wing of the Vienna Circle—and not only with regard to Neurath but also Carnap. Thus he wrote in a short manuscript about the proper conduct of philosophy dating to his final year about himself and “his friends”:

“But in principle our efforts are directed as much towards the questions of ethics as towards those of mathematics, just as much towards the questions worthy to be asked of life as towards those to be asked of the sciences. That is why I cannot at all agree with some representatives of our empiricism when they want to identify philosophy with the ‘logic of science’.” (2013, 484-485, trans. TU)

59 D 302, “Dictation for Schlick”, in Baker (2003, 74). I replaced “down-to-earth” as a translation for “hausbacken” with “homely”.

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There did exist genuine philosophical problems, like skepticism, that demanded attention. Yet it also remains the case that, whatever its success elsewhere, Schlick’s revival of his anti-skeptical focus in epistemology in the new Wittgensteinian vein cost him the relevance for philosophy of science which it still had possessed in his General Theory. The infallible discernment of truth that Schlick now pursued in affirmations (and sought to anchor with reference to Wittgenstein’s conception of linguistic understanding) is alien to science and scientific thinking. Whatever justification affirmations may possess cannot intelligibly be shared intersubjectively. (What can be shared are testimonial reports about the respective experiences, but that is a different matter.) It is this failure to sustain the intersubjectivity of science—not the failure to transfer certainty from affirmations to physical object statements—that disqualifies Schlick’s affirmations from playing a role in the epistemology of science.60 The “central problem” remains unresolved as far as scientific knowledge claims are concerned.

But what about the everyday, ordinary language-based “unquestionable” status of certain of our claims? The disregard of skepticism towards the mostly unreflectively presupposed constancy of our language use must be justified or explained in some fashion if it is not to end in dogmatism. Just this, of course, is what Schlick attempted—by following Wittgenstein’s pointer to the legitimacy of “unthinking” usage—and therein lies, I believe, the indisputable merit of his proposal. Yet insofar as Schlick remained committed to the ideal of the autonomy of individual epistemic agents his attempt remained problematical, for with it he fell back behind Wittgenstein’s then soon beginning engagement in critical reflections about the problem of private language use and understanding. And more than ten years later, of course, Wittgenstein himself turned to the problem of dissolving the problem of skepticism in the notes now known as On Certainty. In light of this it might perhaps be thought that the theory of affirmation could be saved by abandoning the ideal of the autonomy of individual epistemic agents—the price of Wittgenstein’s anti-skeptical therapy—but that would, it seems, have been intolerable for Schlick (1934/1979, 379-380; 1935a/1979, 404). Moreover, until the ambition to refute scepticism is given up, even such a “socialization” of knowledge would still have to be considered dogmatic.

If this is correct, then Schlick’s theory of affirmations remains ultimately unsuccessful even in this interpretation which takes seriously his own ambition to reorient the answer to the old problem of skepticism. So it might appear that little is gained. But to go this far would be to overlook not only that, on this reading, the failure of Schlick’s theory becomes rationally explicable to a greater degree than it been before, but also that as

60 Carnap’s early methodologically solipsist versions of protocol sentences failed for the same reason, as Neurath had forcefully argued; see Uebel (2007, Chs. 6-8).

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an early attempt at anti-skeptical deflationism it becomes much more interesting. That in his discussions with Schlick Wittgenstein always felt a rare community of minds accordingly was due to the sense, apparently palpable to both, that they were reaching for an entirely new understanding of understanding. And it seems entirely possible that, even though they remained unmentioned by Wittgenstein, Schlick’s efforts formed part of the background that prompted his reflections in On Certainty.61 In any case, the question whether the interpretation of Schlick as once more but differently engaged with skepticism is to be preferred to that of an inexplicably failing philosopher of science, appears to be well worth further consideration.62

61 It is pretty inconveivable that Wittgenstein did not read at least Schlick (1934) and (1935a).62 Versions of this paper were presented at international conferences in Rostock, Ghent, Dublin, Helsinki and Sao Paulo. I wish to thank participants at these meetings and two referees for this journal for critical feedback, and particularly Mathias Iven for correspondence concerning Schlick’s Wittgensteinana and the provision of Inv.-Nr. 184, D.5, and Johannes Friedl for correspondence concerning Schlick’s copy of the Blue Book.

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