Murray Miles

This is a very impressive piece of philosophical scholarship, in the best tradition of French-language studies in the history of philosophy and science in the seventeeth and eighteenth centuries. Its theme is Leibniz’s philosophy of science, which, François Duchesneau contends, is at bottom a doctrine of method in the seventeenth-century manner of Descartes. Leibniz’s philosophy of science, however, is as antithetical to the principles of Cartesian science as to those of the “experimental philosophers,” from Boyle and Hooke to Locke and Newton. If Leibnizian science was all but eclipsed by the powerful legacy of Newton and his followers, Leibniz’s philosophy of science, Duchesneau argues, has a special relevance for contemporary discussions of the respective roles of theory and observation, the status of theoretical entities, and the logical structure of scientific theories.

InLeibniz: Perception, Apperception, and Thought, Robert McRae alleges a flat “contradiction” at the heart of Leibniz's doctrine of three grades of monads: bare entelechies characterized by perception; animal souls capable both of perception and of sensation; and rational souls, minds or spirits endowed not only with capacities for perception and sensation but also with consciousness of self or what Leibniz calls “apperception.” Apperception is a necessary condition of those distinctively human mental processes associated with understanding and with reason. Insofar as it is also a sufficient condition of rationality, it is not ascribable to animals. But apperception is a necessary condition of sensation or feeling as well; and animals are capable of sensation, according to Leibniz, who decisively rejected the Cartesian doctrine that beasts are nothing but material automata. “On the one hand,” writes McRae, “what distinguishes animals from lower forms of life is sensation or feeling, but on the other hand apperception is a necessary condition of sensation, and apperception distinguishes human beings from animals”. “We are thus left with an unresolved inconsistency in Leibniz's account of sensation, so far as sensation is attributable both to men and animals”.

In two separate studies, published some four years apart, Robert McRae has argued the provocative thesis that the idea of extension is not to be numbered among the ideas accounted innate by Descartes, but among the adventitious. He has defended this view despite explicit statements to the contrary by Descartes both in the Correspondence and in the second part of the Principles of Philosophy. Against such evidence McRae has urged the overriding importance of the sixth Meditation, where, he alleges, Descartes asserts “unequivocally… that the idea of extension is produced in us by bodies and is therefore not innate”. It is only in the later of the two studies that McRae's reasons for regarding the testimony of the sixth Meditation as authoritative are fully spelt out. Express statements to the contrary “must give away”, he writes, “for the proof of the existence of body by the adventitious idea of it is absolutely crucial to the Meditations”. In this paper I propose to challenge McRae's interpretation of the extension of the concept “innate idea”, while acknowledging his signal contribution to the clearing up of the intensional meaning, or rather meanings, of the concept of innateness. My thesis is that “extension” is an innate idea, though constraints of time will allow me to do little more than try to show that McRae's stated reasons for rejecting this view are not compelling.

It will come as no surprise that I have a different interpretation of the four passages in which, McRae claims, Descartes “definitely includes extension and its modes in what is given through the senses”. In the first, Descartes includes extension, etc., among his ideas of corporeal bodies. This is not to say that he includes them among his adventitious ideas, though. All adventitious ideas are ideas of external bodies. But the converse is not true. Not all ideas of corporeal bodies are ipso facto adventitious ideas, for, as I see it, the idea of the true and immutable nature of body is non-sensible and innate. McRae slides from “all adventitious ideas seem to be ideas of external bodies” to “all ideas of external bodies are adventitious”.

Against those commentators who consider Kant’s explicit reference to Copernicus’s heliocentric reversal either grossly misleading or simply irrelevant to the revolution in philosophy carried out in the Critique of Pure Reason, it is argued in this paper that Kant’s transcendental idealist inversion of the familiar standpoint of realism and sound common sense fully justifies the talk of a ‘Copernican revolution,’ even if Kant himself never used the expression. It is not just the dominant ‘moving spectator’ motif (or transcendental turn) of the Preface that has to do with Copernicus; both the immediately following ‘crucial experiment’ motif (on the distinction between appearances and things in themselves) and the ‘critical’ motif (regarding self-knowledge and the possibility of synthetic a priori judgments) confirm the aptness of the Copernican analogy. Still, some commentators have stretched the analogy too far; the final section of the paper attempts to determine just how far it may reasonably be said to go.

In 1772, Kant outlined the new problem of his critical period in terms of four possible “ways” of understanding the agreement of knowledge with its object. This study expands Kant’s terse descriptions of these ways, examining why he rejected them. Apart from clarifying the historical context in which Kant saw his own achievement (the Fifth Way), the chief benefits of exploring the historical background of Way Two, in particular, are that it (1) explains the puzzling intuitus originarius/intellectus archetypus dichotomy, and (2) casts doubt on the received idea that Kant broke with the traditional theocentric model of cognition.