Abstract

Frank Jackson has argued that, in principle, all mental truths are deducible from all physical science truths: 'deducibility'. Jackson's defence of deducibility relies upon the method for producing naturalistic definitions of mental states championed in the analytical functionalism of himself, David Lewis, and others. Two arguments are presented. The first contends that the particular naturalistic definitions of analytical functionalism fail because they do not take account of the extraordinary kind of bodily animation displayed by human beings, which I argue is necessary to mentality; machines lacking mentality can satisfy the naturalistic definitions of analytical functionalism. So Jackson's defence of deducibility fails as it stands. The second argument contends that no naturalistic conceptual analysis of the mental can be adequate, because understanding mental concepts requires a special kind of affective reaction here named 'personal response', while understanding naturalistic concepts does not require this- therefore no naturalistic analysis can ever capture our common-sense mental concepts. The upshot is that Jackson's defence of deducibility cannot be repaired. No defence of deducibility will work which relies upon the possibility of naturalistic conceptual analyses of mentality