Patricia Churchland

Within the domain of philosophy, it is not unusual to hear the claim that most questions about the nature of consciousness are essentially and absolutely beyond the scope of science, no matter how science may develop in the twenty-first century. Some things, it is pointed out, we shall never _ever_ understand, and consciousness is one of them (Vendler 1994, Swinburne 1994, McGinn 1989, Nagel 1994, Warner 1994). One line of reasoning assumes that consciousness is the manifestation of a distinctly nonphysical thing, and hence has no physical properties that might be explored by techniques suitable to physical things. Dualism, as this view is known, is still to be found among those within the tradition of Kant and Hegel, as well as among some with religious convictions. Surprisingly, however, strenuous foot-dragging is evident even among philosophers of a materialist conviction. Indeed, one might say that it is the philosophical fashion of the 90's to pronounce consciousness unexplainable, and to find the explanatory aspirations of neurobiology to be faintly comic if not rather pitiful. The very word, "reductionism" has come to be used more or less synonymously with "benighted-scientism-run-amok", where scientistm apparently means "applying scientific techniques to domains where they are inapplicable." McGinn, perhaps the most unblushing of the naysayers, insists that we cannot expect even to make any headway on the problem. (p. 114) Ironically perhaps, here we are at a conference in honor of Dr. Herbert Jasper who was a great pioneer in moving neuroscience forward on this problem, and where results will be presented allegedly _showing_ additional progress on the problem. Because I am quite optimistic about future scientific progress on the nature of consciousness, my aim here, as a philosopher, is to address the most popular and influential of the skeptical arguments, and to explain why I find them unconvincing. Thus the overall form of the paper is negative, in the sense that I want to show why a set of naysaying arguments fail.

As neuroscience uncovers these and other mechanisms regulating choices and social behaviour, we cannot help but wonder whether anyone truly chooses anything (though see "Is the universe deterministic?"). As a result, profound questions about responsibility are inescapable, not just regarding criminal justice, but in the day-to-day business of life. Given that, I suggest that free will, as traditionally understood, needs modification. Because of its importance in society, any description of free will updated to fit what we know about the nervous system must also reflect our social need for a working concept of responsibility.

A remarkable hypothesis has recently been advanced by Libet and promoted by Eccles which claims that there is standardly a backwards referral of conscious experiences in time, and that this constitutes empirical evidence for the failure of identity of brain states and mental states. Libet's neurophysiological data are critically examined and are found insufficient to support the hypothesis. Additionally, it is argued that even if there is a temporal displacement phenomenon to be explained, a neurophysiological explanation is most likely.

Explaining the nature and mechanisms of conscious experience in neurobiological terms seems to be an attainable, if yet unattained, goal. Research at many levels is important, including research at the cellular level that explores the role of recurrent pathways between thalamic nuclei and the cortex, and research that explores consciousness from the perspective of action. Conceptually, a clearer understanding of the logic of expressions such as ‘‘causes’’ and ‘‘correlates’’, and about what to expect from a theory of consciousness are required. The logic of some terms, such as ‘‘qualia’’ and ‘‘reductionism’’, continues to generate misunderstandings about the scientific possibilities and limits. Experimentally, a deeper understanding of the role of the thalamus in coordinating activity across cortical levels, and a readiness to reconsider the orthodox approach to thalamocortical organization are also required.

We critically review themushrooming literature addressing the neuralmechanisms of moral cognition (NMMC), reachingthe following broad conclusions: (1) researchmainly focuses on three inter-relatedcategories: the moral emotions, moral socialcognition, and abstract moral reasoning. (2)Research varies in terms of whether it deploysecologically valid or experimentallysimplified conceptions of moral cognition. Themore ecologically valid the experimentalregime, the broader the brain areas involved.(3) Much of the research depends on simplifyingassumptions about the domain of moral reasoningthat are motivated by the need to makeexperimental progress. This is a valuablebeginning, but as more is understood about theneural mechanisms of decision-making, morerealistic conceptions will need to replace thesimplified conceptions. (4) The neuralcorrelates of real-life moral cognition areunlikely to consist in anything remotely like a``moral module'' or a ``morality center.'' Moralrepresentations, deliberations and decisionsare probably highly distributed and notconfined to any particular brainsub-system. Discovering the basic neuralprinciples governing planning, judgment anddecision-making will require vastly more basicresearch in neuroscience, but correlatingactivity in certain brain regions withwell-defined psychological conditions helpsguide neural level research. Progress on socialphenomena will also require theoreticalinnovation in understanding the brain'sdistinctly biological form of computationthat is anchored by emotions, needs, drives,and the instinct for survival.