Psychologia rationalis (review)

BOOK REVIEWS 113 What Leibniz meant by saying that the opposite of "Caesar crossed the Rubicon" is possible, is that there could have been--in a different wodd--a person like Caesar in all respects except that of crossing the Rubicon, with its attendant consequences. He could not, of course, be Caesar, that particular historical person in this world. So, strictly speaking, it is not the case that "Caesar did not cross the Rubicon" could be true. But it is possible for there to be another complex concept which contains a/most all the predicates of Caesar, but which contains "did not cross the Rubicon" instead of "crossed the Rubicon." That is a consistent concept which characterizes an individual in a different possible world which God could have created. (123) But Leibniz would never have accepted the claim that according to his doctrines "strictly speaking, it is not the case that 'Caesar did not cross the Rubicon' could be true"; this was precisely the sort of fatalism his opponents were accusing him of. Rather, his view was that "Caesar did not cross the Rubicon" is true of each possible world which is such that, if it had been created instead of the actual world, Caesar (i.e., Caesar-who-was-going-to-cross-the-Rubicon) would not have existed.27 I have discussed these various points in relative detail because it seems to me that so serious and praiseworthy an attempt as Miss Ishiguro's to make good sense of Leibniz 's doctrines deserves a response in which disagreement, if any, goes beyond the level of mere generalities and is accompanied by citation of chapter and verse. Only in that way is it possible to reach a more satisfactory understanding of so complex a subject as this. BENSON MATES University o/ Cali[ornia, Berkdey Psychologia rationalis. By Christian Wolff. Gesammelte Werke, Abteilung II, Band 6. Herausgegeben und bearbeitet von Jean ]~cole, (Hi/desheim: Georg Olms Verlag, 1972. Pp. lviii+lS*+821. DM 118) This is the twenty-eighth volume to be published out of a projected fifty-one in the publisher's ambitious attempt to provide a new and comprehensive edition of the works of the German philosopher, Christian Wolff (1679-1754). It is also the fourth to appear under the editorship of Professor Jean ]~cole, having been preceded by the Philosophia prima sire Ontologia (1962), Cosmologia generalis (1964), and Psychologia empirica (1968). 1 The Psychologia empirica and the Psychologia rationalis combine to form a unitary statement of Woltt's philosophical psychology. And these, together with the earlier two volumes and two which are yet to appear on natural theology, constitute the six-volume Latin statement of Wolff's metaphysics. We must now look forward to the early appearance of Professor ~cole's edition of the natural theology volumesz in 27 For Leibniz, "Caesar did not cross the Rubicon" is true if and only if "Caesar crossed the Rubicon" is not true; tertium non datur. 1 See my review of these three volumes in this Iournal, IX (1971), 513-516. Professor l~cole has also provided a brief preface for Wolff's Ratio praelectionum which has recently appeared in the Gesammelte lYerke (Abteilung II, Band 36: 1972; originally 1718). The text is an interesting one, consisting of a kind of overview of the plan of Wolff's lectures in the various parts of mathematics and philosophy. It has, however, simply been photocopied with the addition of the new preface; it has not been given the careful editorial concern of the volumes discussed in this and the previous review. 2 An interesting point for comparison between the psychology and natural theology volumes will be the parallel distinctions between empirical and rational psychology on the one hand (discussed below and in the previous review) and the a posteriori and a priori parts of natural theology on the other. 114 HISTORY OF PHILOSOPHY order to come to a contemporary understanding of Wolff's views on God and to appreciate his mature metaphysics as an integrated whole. Thereafter, we can expect Professor ]?.cole to proceed to the editing of the Discursus praeliminaris de philosophia in generea and the Philosophia rationalis sire Logica (originally published...