Kant's Attack on Rational Psychology
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Stephen Priest Page 1 05/12/2007 KANT’S ATTACK ON CARTESIAN DUALISM Stephen Priest Stephen Priest is a member of the Faculty of Philosophy in the University of Oxford. He is Senior Research Fellow of Blackfriars Hall, Oxford and a member of Wolfson College, Oxford and Hughes Hall, Cambridge. He is the author of The British Empiricists, Theories of the Mind, Merleau-Ponty, and The Subject in Question, editor of Hegel’s Critique of Kant, Jean-Paul Sartre: Basic Writings and co- editor (with Antony Flew) of A Dictionary of Philosophy. Stephen Priest has lectured widely in the United States and Europe and his writing has been translated into Dutch, Spanish, Russian, Japanese, Korean and Macedonian. © Stephen Priest December 2007 A Priori Subjects: Kant’s Attack on Cartesian Dualism Stephen Priest Page 2 05/12/2007 Preface In parts of the Critique of Pure Reason Kant offers arguments for the conclusion that the solutions to some problems of the self do not entail the existence of an immaterial soul. My restricted aim in short book is to decide whether any of them is sound. Because this is a philosophy book, not a work in the history of ideas, I have not attempted to reconstruct the whole of Kant’s thinking about the self, nor to locate it in a historical context. In philosophy, the relevant units are the problems, their putative solutions and the arguments for those putative solutions. My approach to Kant is more like Jonathan Bennett’s than those of Karl Ameriks or Paul Guyer. By ‘understanding’ Kant I mean the allocation of propositions to his sentences in a way that maximises their consistency as a set. The justification of this method is: To the extent to which some sentences form an inconsistent set they express nothing. I point out places where Kant’s arguments have been misunderstood by the major commentators and substitute more viable interpretations. Because we operate in an anti-metaphysical age, in which Cartesianism is held up as a paradigm of philosophical falsehood, commentators tend to be sympathetic to Kant’s attack on rationalist psychology. I argue that the problems, once understood in their profundity and with clarity, can only be solved if we are in fact souls. This book is therefore unusual in being a defence of the conclusions of ‘the rationalist psychologist’ against Kant’s attack. I thank A. J. Ayer, Graham Bird, Edward Craig, Daniel Came, Benedikt Göcke, Peter Hacker, Michael Inwood, Adrian Moore, Terence Penelhum, Bernard Williams and Timothy Williamson for discussion of Kant’s philosophy or problems of the self or both. I am grateful to the Philosophische Fakultät of the Westfälische Wilhelms- Universität Münster, Germany for their hospitality in 2006. In particular I thank, Prof. Dr. Andreas Hütteman, Prof. Dr. Harald Holz and Prof. Dr. Peter Rohs for useful discussion of the invited lectures I delivered there about Kant. I also thank the Faculteit der Filosophie of the Radboud Universiteit, Nijmegen, Netherlands, for their hospitality, also in 2006. In particular I thank Professor Graham Lock, and Tjeerd and Sjoerd van Hoorn for their contributions to a two-day seminar generously devoted to my ideas. Stephen Priest Michaelmas Term 2007 Oxford A Priori Subjects: Kant’s Attack on Cartesian Dualism Stephen Priest Page 3 05/12/2007 Contents I. Kant’s Attack on Immaterial Substance 4 II. Simple Souls and the Unity of Consciousness 20 III. The Problem of Personal Identity 44 IV. The Refutation of Idealism 93 V. The Paradoxes of Inner Sense 117 A Priori Subjects: Kant’s Attack on Cartesian Dualism Stephen Priest Page 4 05/12/2007 I Kant’s Attack on Immaterial Substance In the Critique of Pure Reason, Kant calls the project of proving Cartesian dualism by a priori means 'rational psychology'. (1) The structure of Kant's argument against the possibility of rational psychology is: (1) 'The proposition 'I think' (taken problematically) contains the form of each and every judgement of the understanding and accompanies the categories as their vehicle.' Da nun der Satz: Ich denke, (problematisch genommen,) die Form eines jeden Verstandesurteils überhaupt enthält, und alle Kategorien als ihr Vehikel begleitet (2) 'It is evident that the inferences from it admit only of a transcendental employment of the understanding.' So ist klar, daß die Schlüsse aus demselben einen bloß transzendentalen Gebrauch des Verstandes enthalten können (3) 'This employment excludes any admixture of experience.' Welcher alle Beimischung der Erfahrung ausschlägt (4) 'We cannot, after what has been shown above, entertain any favourable anticipations in regard to its methods of procedure.' Und von dessen Fortgang wir nach dem, was wir oben gezeigt haben, uns schon zum voraus keinen vorteilhaften Begriff machen können. (CPR 368, B406)(1) His claim in (1) that the expression 'I think' contains the form of every judgement, is a formal requirement on any judgement that it admit of being couched in first person singular grammatical form, and thereby could in principle be thought. This constraint is familiar from the doctrine of the transcendental unity of apperception: If a judgement it to count as such, and be an episode in a self-conscious rational mind, it must logically admit of re-phrasing using the sentential prefix 'I think [...]'. If it were A Priori Subjects: Kant’s Attack on Cartesian Dualism Stephen Priest Page 5 05/12/2007 logically impossible for a putative judgement to be couched in this form, then it could not be an occurrence in a self-conscious rational mind, so could not be a thought, and so could not be a judgement either. It is for Kant a necessary truth, because analytic, that a person thinks their own thoughts, and all thoughts are somebody's, so the proposition 'I think my thoughts' is analytic. It follows that 'I think my thoughts' is not a material or informative sentence, and the 'I think […]' prefix is merely a formal requirement on my thinking and does not give any information about my nature. It is because the 'I think' accompanies judgements as a formal condition for their existence that it is also a formal condition on the use of the categories. If the categories' only use is in judgements, and if the possible employment of the 'I think [...]' prefix is a condition of the use of judgements, then it follows that the possible use of the 'I think' prefix is a condition for the use of the categories also. (1) then, expresses synoptically Kant's theory of the correct use of 'I think', and exhausts the essentials of what is philosophically legitimate to claim about it. The second premise, (2) follows from (1) if (1) is correctly understood. If the possibility of the 'I think [...]' prefix accompanying the use of judgements is a condition for the use of judgements, then that is a transcendental fact about it. If that fact about the 'I think' is the only fact about it that is philosophically well-founded, then the transcendental fact about it is the only fact about it that is philosophically well-founded. Further, if the 'I think' admits only of a transcendental employment, then any sentence which may be logically derived from 'I think' must admit also of only a transcendental employment. This is why for Kant it is 'evident' that the inferences obtained from 'I think' will have only a transcendental import. He means logically evident. (2) follows from (1) because no transcendental fact is an empirical fact. Kant would not wish to deny that the sentence 'I think' has an empirical use, nor that the expression might have an empirical use when prefixed to a judgement. But from the fact that an expression possess both a transcendental and an empirical use it does not follow that the transcendental use possesses any empirical features, or that the empirical use possesses any transcendental feature. Indeed, Kant insists that transcendental and empirical descriptions are mutually exclusive (and collectively exhaustive) so that if p expresses a transcendental fact than qua transcendental fact it is not an empirical fact, and if p expresses an empirical fact then qua empirical fact it is not a transcendental fact. Clearly, this is quite consistent with one and the same set of words being used to express both transcendental and empirical facts. So, by (2) Kant is claiming that the transcendental unity of apperception's 'I think' is a transcendental fact; a condition on self-conscious thought, and qua transcendental fact it admits of only a transcendental use. No empirical facts follow from 'I think' construed transcendentally. (3) follows from (1) and (2) because if 'I think' is a transcendental fact then qua transcendental fact its use is not empirical. If it were empirical it would include an A Priori Subjects: Kant’s Attack on Cartesian Dualism Stephen Priest Page 6 05/12/2007 'admixture of experience', that is, it would express information that could be inferred from experience. In (4) we have to read 'favourable' to mean 'metaphysically favourable' or 'favourable to the projects of rational psychology'. Kant thinks nothing non- transcendental follows from 'I think' so, a fortiori not only does nothing empirical follow from 'I think' but nothing metaphysical either. So, in (4), 'after what has been shown' refers back to the first three premises interpreted according to the theory of the transcendental unity of apperception, and 'its methods of procedure' refers to the transcendental method of treating ' I think'. Kant's argument is valid, and if the premises are true then it is also sound, but accepting those premises largely depends on accepting the central doctrines of the transcendental deduction, so accepting the conclusion depends on accepting those doctrines also.