is there reason for skepticism? joe cruz williams college philosophy and cognitive science thanks to...
TRANSCRIPT
Is There Reason
for Skepticism?Joe Cruz
Williams College Philosophy and Cognitive Science
Thanks to Jonathan Vogel, Melissa Barry, Alan White, Will Dudley, Tom Kelly, Joe Sheiber, Brad Armour-Garb, and Jonathan Greco for conversation on these issues.
Skepticism• Skeptical arguments aim to be
rationally persuasive.• And therefore must appeal to
epistemic principles.
Skepticism• Skeptical arguments aim to be
rationally persuasive.• And therefore must appeal to
epistemic principles; this has often been taken to show that skepticism must be limited.
Skepticism• Seems to retain a potent
repertoire of arguments even if a commitment to reason must be preserved.
My Project• Show that skepticism is a result
of tensions between individual epistemic principles; this might lead to a kind of pragmatic resignation.
My Project• Show that skepticism is a result
of tensions between individual epistemic principles; this might lead to a kind of pragmatic resignation.
• Explore a more confident response to skepticism by arguing that the way the skeptic uses epistemic principles undermines skepticism itself.
Epistemic principles• Rules that state the conditions
under which a set of inputs yields (epistemically) high-quality output.
Epistemic principles• Rules that state the conditions
under which a set of inputs yields (epistemically) high-quality output.
• Prescriptive (though they may retain significant debts to descriptive theories of cognition).
Epistemic principles Examples:
“If a person has a clear sensory impression that x is F (or of x's being F) and on that basis believes that x is F, then this belief is prima facie justified” (Audi, 2001, p. 43).
“If S believes that he perceives something to have a certain property F, then the proposition that he does perceive something to be F, as well as the proposition that there is something that is F, is one that is reasonable for S” (Chisholm, 1966, p. 45).
Epistemic principles Examples:
“Having a percept at time t with the content P is a defeasible reason for the cognizer to believe P-at-t” (Pollock and Cruz, 1999, p. 201).
Epistemic principles Generic Schema:
Being in mental states 1,...(n-l) is a good (but defeasible) basis for an inference to mental state n in the cognizer.
Epistemic principles• Are content-neutral.• Are not consciously explicit.• Supervene on agent’s
psychology.
Skepticism Reconsidered Skeptical arguments
Offer the mere possibility of an alternate incompatible but equally explanatory hypothesis.
Skepticism Reconsidered Skeptical arguments
Offer the mere possibility of an alternate incompatible but equally explanatory hypothesis.
Are all such possibilities cogent?
Skepticism Reconsidered• Conclusions can’t be rationally
distinguished on the basis of collateral evidence.
Skepticism Reconsidered• Conclusions can’t be rationally
distinguished on the basis of collateral evidence.
Cartesian (or external world)
skepticism
Skepticism about memory
Humean skepticism
Skepticism Reconsidered What principle?
If S possesses some evidence e, and if e does not discriminate between two or more conflicting conclusions, then it is not rational for S to believe one of those conclusions.
Call this the discriminating evidence principle.
Skepticism Reconsidered Discriminating Evidence Principle
Is it content-neutral?
If it is*, then DE can be applied to arguments that use other principles, and this is precisely what skepticism does.
* Reflection, Generality of cognition
Skepticism Reconsidered An argument for Commonsense Realism
(1) I appear to have two hands.
(2) Therefore, it is reasonable for me to
believe that I have two hands.
Skepticism Reconsidered An argument for Commonsense Realism
(1) I appear to have two hands.
(2) Therefore, it is reasonable for me to
believe that I have two hands.
Perceptual Principle
e.g., “If a person has a clear sensory impression that x is F …and on that basis believes that x is F, then this belief is prima facie justified” (Audi).
Skepticism Reconsidered Against Commonsense Realism
(1) I appear to have two hands.
(2) Therefore, it is reasonable for me to
believe that I have two hands.
(3) I may be deceived by an evil demon, therefore
it is not reasonable for me to believe that I
have two hands.
Perceptual Principle
Skepticism Reconsidered Against Commonsense Realism
(1) I appear to have two hands.
(2) Therefore, it is reasonable for me to
believe that I have two hands.
(3) I may be deceived by an evil demon, therefore
it is not reasonable for me to believe that I
have two hands.
Perceptual Principle
Discriminating Evidence Principle
Skepticism Reconsidered Pragmatic Resignation
• Perceptual principle and DE are both constitutive of cognition.
Skepticism Reconsidered Pragmatic Resignation
• Perceptual principle and DE are both constitutive of cognition.• In mundane contexts, they tend to conflict only locally.
Skepticism Reconsidered Pragmatic Resignation
• Perceptual principle and DE are both constitutive of cognition.• In mundane contexts, they tend to conflict only locally, but once made conscious can conflict globally.
Skepticism Reconsidered Pragmatic Resignation
• So we must weigh our susceptibility to skeptical arguments against the value of our cognition.
Skepticism Reconsidered Discriminating Evidence Principle
Is it content-neutral?
If it is not*, then skepticism itself may be in danger.
* Domains of reason, evolution
Skepticism Imploded? Some cases
(1) I remember clearly and vividly that my
capacity for applying DE is defective.
(2) Therefore, it is reasonable for me to
believe that my capacity for applying DE is
defective.
Skepticism Imploded? Some cases
(1) I remember clearly and vividly that my
capacity for applying DE is defective.
(2) Therefore, it is reasonable for me to
believe that my capacity for applying DE is
defective.
Memory Principle
Skepticism Imploded? Some cases
(1) I have accumulated a lot of evidence that my
capacity for applying DE is defective.
(2) Therefore, it is reasonable for me to
believe that my capacity for applying DE is
defective.
Skepticism Imploded? Some cases
(1) I have accumulated a lot of evidence that my
capacity for applying DE is defective.
(2) Therefore, it is reasonable for me to
believe that my capacity for applying DE is
defective.
Inductive Principle
Skepticism Imploded?• These cases show that it is possible for someone reasonably to believe that her capacity for deploying DE is defective.
Skepticism Imploded?• These cases show that it is possible for someone reasonably to believe that her capacity for deploying DE is defective.• The mere possibility of these cases can be used in a DE-based argument against skepticism.
Skepticism Imploded?(1) I appear to have two hands.
(2) Therefore, it is reasonable for me to
believe that I have two hands.
(3) I may be deceived by an evil demon, therefore
it is not reasonable for me to believe that I
have two hands.
Perceptual Principle
Discriminating Evidence Principle
Skepticism Imploded?(1) I appear to have two hands.
(2) Therefore, it is reasonable for me to
believe that I have two hands.
(3) I may be deceived by an evil demon, therefore
it is not reasonable for me to believe that I
have two hands.
(4) I may be mis-applying DE, therefore it
is not reasonable for me to retract my
earlier argument.
Perceptual Principle
Discriminating Evidence Principle
Skepticism Imploded?(1) I appear to have two hands.
(2) Therefore, it is reasonable for me to
believe that I have two hands.
(3) I may be deceived by an evil demon, therefore
it is not reasonable for me to believe that I
have two hands.
(4) I may be mis-applying DE, therefore it
is not reasonable for me to retract my
earlier argument.
Perceptual Principle
Discriminating Evidence Principle
Discriminating Evidence Principle
Skepticism Imploded?• But skepticism does not seem incoherent. What is going on?• We can have a pragmatic resignation toward the apparent implosion of skepticism.