An examination of the philosophy of substance and its relation to the philosophy of mind, with special reference to Aristotle and Descartes, and their conceptions of science

The confused character of theory of mind (Ch.I) parallels confusion as to the status of "substance" (Ch.II). The philosophical problem is that of relating incompatible theses, and especially of discovering what is involved in modes of argument employed by metaphysicians in toms of "mind" and "substance", since these produce a fantastic set of "conclusions". Types of argument to "necessary substances" can be shown to be vacuous. But it remains to show that these are actually employed by philosophers. Descartes does employ such arguments (Ch.Ill), and his "necessary substances" cannot be related to "actual substances". The "unity of man" and the truth of observation statements are his real problems. As a conceptual system his dualism is of kinds of thing, and presents no problems; but he treats it confusedly as "definitional" and related to empirical science. It is then a metaphysical dualism. His arguments to an unextended thinking substance are complex and invalid. The Cogito does not reduce the sensing agent to a soul; and Descartes' theory of science treats Thought, not the thinking agent, as substantial. (Ch.V). His theory of soul and thought is Socratic and untenable as a theory of thought or of science (Ch.VI - developed in Ch.VIl). The identification of Subject, Substance and Thing, when considered in relation to fact statements and natural science (Ch.VIIl) enables us to develop a theory of logic in an Aristotelian manner. Descartes' "two substance" thesis depends, upon this logic for its "necessity", and is logically incoherent. Descartes rejection is really of common nouns; he substitutes for them "soul" and "body", not "substance". Once (Ch.VII) the contrast is made clear between patterns of simple notions and human thinking and science, the issue becomes one of finding reasons for rejecting fact-values for the variables of propositions in logic. Descartes wants fact-predicates,e.g. "thinking", and the vital claim is that there are manifold "qualities* of mind. But none of these can be discovered (Ch.IX) even if we go beyond Descartes' own writings in search for them.The second great use of "substance" is correlative with"form". Contrasting "mental" and "material" substance we find that what holds these theses in meaningful opposition is History and history, as previously it was fact statements in a natural language and occurrences. We are now able (Ch.X) to relate (a) statements in logic, (b) statements in History, and (c) metaphysical or category statements. These last are equivalent to statements about classes of statements necessary to History and its accounts of historical individuals.This is related (Ch,Xl) to uses of "thing" and "substance" in ordinary discourse, and Aristotle's logical, categorial and metaphysical concepts are derivable from this. In Ch.XII the central doctrine of the De Anima is shown to relate logic, metaphysics and classificatory natural science, definitions and observation statements - from such a system are drawn the terms which Descartes and other metaphysicians treat as meaningful independently of statements in natural science. It is contended that without natural science, logical and metaphysical truths are ontologically vacuous. We conclude with the endorsement of "substance" as a valid category or metaphysical term, and the rejection of "a metaphysical substance" and "a metaphysical subject" as meaningless expressions; with the endorsement of statements about men doing science, empirical and rational, and the rejection of metaphysical arguments to minds or souls as doing science, empirical or rational.