Mind and Emergence: From Quantum to Consciousness. Philip Clayton. New York: Oxford University Press, 2004 (cloth) and 2006 (paper). xii + 236 pp. ISBN 0-19-927252-2 (cloth) and ISBN 0-19-929143-8 (paper). $74.00 (cloth) and $27.95 (paper). After waning in the early part of the twentieth century, emergentism has re-emerged with vengeance. Philip Claytons Mind and Emergence represents both the promise and the peril of the growing literature on the topic. The title may suggest that Clayton thinks of emergentism, as many today do, as a thesis about the nature of the mind. But for Clayton emergentism is an interpretive framework through which to investigate and understand all of natural history, as the subtitle suggests. Such is the promise of emergentism: an interpretation of everything. The peril is obvious: a misunderstanding everything. The competitors of the emergentist framework are physicalism and property dualism. (He does not consider substance dualism a serious alternative.) Physicalism is committed to a reductive account of all phenomena, and expects the complete causal history of the world to be told ultimately in terms of the entities and laws of physics. Dualism, as Clayton uses the term, is committed to a non-reductive account of at least some mental properties, and expects the complete causal history of the world to be told in mental as well as physical terms. Claytons emergentism is not, like some versions, attempting to occupy the middle ground between physicalism and property dualism. His view is further away from physicalism than dualism. Like dualism, his emergentism is committed to the claim that some properties slip the physicalists net. But unlike dualism, he does not reserve this status for mental properties alone. He is a property pluralist, taking non-reductionism and independent causal influence to be a pervasive occurrence in the natural world. The sort of causal influence Clayton attributes to emergent phenomena is, furthermore, strong. He is not merely committed to the claim that the ontologically novel properties of physical systems are constraining factors in subsequent changes of the systems physical parts. That amounts to weak emergence. Strong emergence requires downward causation; it requires the irreducible properties of physical systems to bring about changes in the systems physical parts. Claytons thesis, then, is that strong emergentism is a viable interpretation of natural history. To establish this thesis, he needs to show that the strong emergentists framework provides a defensible interpretation of mental as well as other phenomena. For strong emergentism to be a defensible interpretation of phenomena, the phenomena must resist physicalist, dualist, and weak emergentist interpretations. Otherwise, the strong emergentist would be positing irreducible centers of causal influence gratuitouslywhich is not defensible. This is the support Claytons thesis needs, not the support it gets. After discussing the history of the emergentist program in Chapter 1 and various concepts of emergence Chapter 2, Clayton offers the main lines of support for his thesis in Chapters 3 and 4. In Chapter 5 Clayton turns to examine the consequences of his emergentism vis--vis the transcendent. Unfortunately, the discussion falters at the crucial points of Chapters 3 and 4, the effect of which diminishes the interest of Chapter 5, which we pass over. Chapter 3 provides examples of emergence from the natural sciences. Although Clayton discusses several physical and chemical illustrations of emergence, biology,

especially the ecological and evolutionary sciences, offers the most fertile ground for the emergentist interpretation. He distinguishes four components at the level of biological emergence. The first is scaling, in which properties and structures emerge as the system becomes more complex. Feedback loops are the next component, appearing as new relationships are formed from scaling up which are responsible for regulating complex processes. Global structures are next; they arise from instantiation of feedback loops to influence the local structures that gave rise to them. Finally, there are nested hierarchies in which global structures form discrete components within an even larger system (pp. 78-84). Thus, an ecosystem represents an emergent phenomenon because it harnesses and enhances the complexity of lower levels. Is this an example of strongly emergent non-mental phenomena? To defend the affirmative answer Clayton must show that an ecosystem has causally active properties which are not reducible to the properties of the systems parts. Clayton never identifies precisely which ecological properties are supposed to be irreducible and why. He never argues for example that there neither are nor can be bridge laws from organism behavior to global structures. But suppose we grant him the irreducible properties. His argument falters still. For, as he concedes, the scientific phenomena he discusses are open to weakly emergent interpretations, and these interpretations are to be preferred where the data allow it. What he needs, then, is a clean-cut case in which the data strongly resist a weak interpretation. He does claim that there are such cases in Chapter 3, but does not say which. Instead, he actually says that the impetus for embracing a strong interpretation of cases that could go either way is the fact that a strong interpretation is required for some mental phenomena (pg. 101). There is no reason whatsoever for his opponents to grant this point. Clayton is on stronger ground in Chapter 4. Here the topic is the emergence of mental properties. This time Clayton at least mentions some important arguments for the irreducibility of phenomenal properties. But when it comes to showing that these properties are causally active, and not merely epiphenomenal, the argument is once again a disappointment. Clayton is aware of the difficulties surrounding the very idea of the causal influence of mental properties, and also aware of the determinist interpretations of human agency. He seems to think the notion of downward mental causation is less problematic within the emergentist framework. Perhaps the idea is that the interaction of mental and brain state is somehow easier to comprehend if the brain state is itself understood as an emergent phenomenon. But the suggestion is no more than that; it is neither explicated nor defended. Similarly, Clayton suggests that a psycho-somatic account of the human personwhich sees the person as a unity of properties which emerge within biological, mental, social and cultural contextssomehow eases the conceptual demands of the free will debate (142). An interesting suggestion, but no more. Todd Buras, Assistant Professor of Philosophy, Baylor University James A. Marcum, Professor of Philosophy, Baylor University.