Solution of the Problem of Species

SOLUTION OF THE PROBLEM OF SPECIES * I. INTRODUCTION 1. In the opening pages of Problems for Thomists: The Problem of Species/ I distinguished two senses in which philosophers use the word "problem": either "to signify an open question, an issue or dilemma not yet demonstratively resolved," or " to mean a question to which several contrary answers have been given, among which we are able to discriminate the true from the false." 2 Strictly speaking, the latter is a solved problem, and as solved it is no longer a problem for purely philosophical inquiry. It may, however, remain a problem for the philosopher in his role as historian of thought. There is both philosophical and historical interest in trying to account for the origin and persistence of theories we know to be false. But in the case of the unsolved problem, the primary aim is philosophical: it is to resolve an issue constituted by conflicting theories, each of which is possible, and neither of which is known to be true. I proposed the problem of species as a problem for philosophical inquiry because I thought I had found an unresolved opposition between two theories about the number and order of species, as these matters ~re discussed in the philosophy of nature. Let me report at once the formulation which I made of this issue. With respect to the number of species (the number of specific distinctions among corporeal substances), the issue was between a first theory which supposed a small and definitely known number (more than three and less than ten), and a second theory which supposed a larger and not definitely known number. With respect to the order of species, the issue was between a first theory which affirmed a perfect hierarchical ordering but denied, in doing so, the presence in two proximately related specific natures of a common generic element ; and a second theory ·which denied a perfect hierarchical ordering but affirmed the presence of a common generic nature in diverse species.8 *An analytical outline of this article will be found on pages 878-9. 1 For brevity, I shall hereafter refer to the book as The Problem of Species. I shall also have to assume that the reader of this article is somewhat familiar with matters under discussion in the book (New York, 1940), or in the series of articles published in THE THOMIST (Vol. I, Nos. 1, 2, 8; Vol. II, Nos. 1, 2) . • Op. cit., p. 1; THE THOMIST, I, 80. • This summary of the issue is, of course, too brief to be adequate. For a full summary, vd. op. cit., Chap. VI; THE THOl\U:ST, I, 481 ff. It must suffice here to point out that there is a connection between what each theory holds about the ~79 280 MORTIMER J. ADLER The problem which I proposed as philosophical no longer seems to me to be a problem of that sort, because I now think that the issue between the two theories can be completely resolved. To state my present view more accurately, I should say that the questions about the number and order of specific natures can be demonstratively answered. This is more accurate because the issue cannot be resolved in favor of either theory as previously formulated. I might describe the situation as I now see it in either of two ways: (I) by saying that there is a third theory which is able to combine the truths contained in the first and the second theory a,nd, at the same time, excludes their errors-a sort of Hegelian synthesis of the halftruths contained in thesis and antithesis; (2) by saying that the first theory contained an accidental error, the rectification of which permits it to be proved, whereas the second theory is essentially erroneous and can, therefore, be completely disproved. Only the second of these two statements is really accurate, and therefore I must describe the situation in that way. The reader will see this to be the case when, later, he sees that the error made in the formulation of the first position is appropriate, but not essential, to its disagreement with the second position, so that when the...