Leibniz's Philosophy of Logic and Language (review)

106 HISTORY OF PHILOSOPHY of this lamentable improving of Nicholas into an absolute idealist are too numerous to cite. The rico-Platonic Christian theology of Nicholas is not a lisping Hegelianism but an entirely different metaphysics, making excellent sense in its own terms and in no need of modernization. The scholarly value of Dangelmayr's learned work is much diminished by such disastrous reinterpretations. PAUL J. W. MILLER University o/ Colorado Leibniz's Philosophy of Logic and Language. By Hid6 Ishiguro. (London: Duekworth, 1972). The task of extracting a coherent philosophy of logic and language from the thousands of items that constitute the Leibnizian corpus is not an easy one. It is much more like the task of fitting a curve to a scattering of points than like that of putting together the pieces of a jig-saw puzzle; no matter what solution one proposes, there will always be Leibnizian statements (often not to be lightly dismissed as "careless") that do not fit in. Nor, of course, should this surprise us, for it would surely be a miracle if all the books, articles, letters, drafts, and jottings of 50 years of an intensely active intellectual life presented a completely consistent and gap-free body of philosophical theory. In the present book Miss Ishiguro sets out to substantiate in detail her conviction "that Leibniz's philosophy of logic and language makes far more sense in every aspect than has generally been thought" and that "many of his views contain insights which have been fully articulated only by twentieth-century logicians and philosophers" (16). 1 Accordingly, she says, she tries "deliberately to consider Leibniz's arguments with reference to logical problems as they are discussed now, rather than just within the setting of the debates of his time." Such an approach is certainly legitimate and praiseworthy; the very least that can be said in its favor is that Leibniz himself would undoubtedly have preferred us to consider his philosophy with the help of all the insights and acumen we can bring to bear upon it, rather than to treat it as a mere historical curiosity, only to be discussed "in its own terms." Students of Leibniz will find Miss Ishiguro's exegesis especially interesting because of the fact that on a number of relatively fundamental points she offers interpretations that deviate substantially from what has become the more-or-less orthodox view. In what follows I consider a number of these points in some detail, on occasion citing evidence that seems to conflict with the account she gives. I. THE Salva Veritate PRINCIPLE Miss Ishiguro begins her analysis with an interpretation of the famous Leibnizian principle, Eadem sunt quorum unum in alterius locum substitui potest, salva veritate, ut Triangulum et Trilaterum, Quadrangulum et Quadrilaterum.2 Leibniz formulated this principle in various Nays, all of which give 1 Numerals in parentheses refer to page numbers in Miss Ishiguro's book. Other abbreviations are: G = Die philosophischen $chriften yon G. W. Leibniz, ed. C. I. Gerhardt, I-VII (Berlin, 1875-1890); C = L. Couturat, Opuscules et #agments in~dits de Leibniz (Paris, 1903); LH = E. Bodemann, Die Leibniz-Handschriften (Hanover, 1889); Grua -- Leibniz, Textes inddits, ed. G. Grua, 2 vols. (Paris, 1948); S = Leibniz, Fragmente zur Logik, ed. P. Schmidt (Berlin, 1960); PLP = Leibniz, Logical Papers, transl. (3. H. R. Parkinson (Oxford, 1966); Loemker = Leibniz, Philosophical Papers and Letters, transl. L. E. Loemker, 2nd ed. (Dordrecht -Holland, 1969). 2 G VII 219. For later use I include the reference to Triangulum, Trilaterum, etc. BOOK REVIEWS 107 an unfortunate appearance of use-mention confusion. For it would seem that names or other linguistic expressions are what are supposed to be interchanged, while the things named are or are not identical. Thus the name "Paris" is not identical with the name "Alexander," and it seems entirely impractical to "substitute" Paris himself for anything, even for Alexander. Miss Ishiguro proposes to rescue Leibniz from this appearance of confusion by interpreting his principle as providing a criterion for the identity of concepts, and not for that of things that fall under the concepts. She understands the content of the principle to be the following: "To say of two...