ARISTOTLE various creatures are adapted by nature for this purpose. 9th, The elaborate treatise, in five books, On Generation of Animals, works out this subject with astonishing fulness. And, IQth, the great work entitled Researches about Ani. tnals, in ten books, in which Aristotle exhibits an acquaint ance, more or less intimate, with about 500 species, 1 crowns the series of his physical writings, and certainly constitutes one of his greatest achievements. There were two other treatises which Aristotle had proposed 2 to himself to write, as belonging to this irpay- (jiaT^ia, or department, namely, one On the Physiology of Plants, and one On Disease and Health, so far as belongs to Physical Philosophy. But neither of these intentions, so far as we know, was executed by him. Last of Aristotle s extant and undoubted works, we have to deal with the Metaphysics. We cannot accept the opinion expressed by Valentine Rose 3 that this work was written before the Physical Discourse and the other kindred books which have just been enumerated. Doubtless many of the metaphysical conceptions were pretty complete in Aristotle s head before he wrote on physics, but that is another question. The very name " Metaphysics" (see before, note 8, p. 514) embodies a strong tradition that the work to which it has been applied came "after the physical works." Secondly, There is another tradition 4 that this treatise was sent to Eudemus for revision, and that while Eudemus was suggesting some improvements in the arrange ment, Aristotle died. Thirdly, there are four places 5 in the physical writings which put off the discussion of certain questions as belonging to "first philosophy," just as in the Ethi&P other questions are put off as belonging to physics. Fourthly, The Metaphysics are quoted in no genuine work of Aristotle s, but only in the book On the Motion of Animals, 7 now generally attributed to a later Peripatetic. Fifthly, The doctrine of causes seems to be handled in a more mature way in the Metaphysics than in the physical writings. Sixthly, In no less than twelve places 8 of the Metaphysics the physical treatises appear to be referred to. There is good ground, then, both external and internal, for believing that the Metaphysics were among the latest of Aristotle s works, and they were certainly not finished by him. As the work stands in Bekker s edition, it consists of thirteen books, exclusive of the brief fragment which suc ceeds book i., and is marked as A EAATTON, or I. Minor. This fragment was attributed by ancient 9 tradition to 1 asides, and is probably un- Aristotelian. It merely contains 1 See Die Thicrarten dcs Aristotcles, von der Klassen dcr Siiugethiere, Viijd, lleptilien, und Insecten, von Carl J. Sundevall, Uebersetzung nua dcm Schwedischen (Stockholm, 1863). Prof. Sundevall estimates the total number of mammals indicated and described by Aristotle 1 1 have been about 70; of birds, 150; of reptiles, 20; and of lishes, 116; making altogether 356 species of vertebrate animals. Of the invertebrate classes, about 60 species of insects and arachnids seem to have been known to Aristotle ; some 24 crustaceans and annelids, and about 40 molluscs and radiates. See The Natural His tory Review for 1864, page 494. 3 De Sensu, iv. 14 ; De Gen. Animal, i. 2, 1 ; De Long. Yit., i. 4, vi. 8. In Hist. Anim., . 1,4, Sxrirfp t iptrai Iv rfj Betapia. rfj irepl Tciv Qvriav, tVpTjrcu is probably a misreading for eto^o-erai. 3 De Ar. Lib. Orel, et Auct., pp. 135-232. 4 See Brandis, Schol. in Arist., 519, b. 33.
- Quoted by Bonitz, Ar. Metaphysica (Bonn, 1849), p. 4.
c Kth. Nic., viii. 1, 7, &c. 7 This little treatise bears all the marks of being a monograph in vbieh the conclusions out of various parts of Aristotle s physical, psychological, and metaphysical writings are amplified and brought tether. Rose gives arguments to show that the physiology of this book, and of the treatise On Breath, belongs to a medical school (Traxagoras, Erasistratus, &c.) later than the time of Aristotle. He ivlmits the De Motu Animal, to have been compiled by some very ul.Ia Peripatetic, De Ar. Lib. Ord. et Auct., pp 162-174 8 See Bonitz. p. 5 9 See Brandis, Schol. in Arist., f. 589, a. 41. some very general remarks on the search for principle^. Book iv. is a sort of glossary of the various meanings in which certain philosophical (but not exclusively metaphysi cal) words are used. It may have been jotted down by Aristotle himself, and have been found among his papers ; but it is only through injudicious editing that it can have been inserted in this work. Book x. is quite peculiar ; the first half of it (chapters 1-7) is a brief restatement (by Aristotle himself, as Bonitz thinks) of the conclusions of books ii. iii. v.; the second half is an un-Aristotelian epitome of part of the Physical Discourse. Even making these deductions, the remainder of the work is not homo geneous, but is resolvable into two separate treatises : the first being intended to set forth Aristotle s system of meta- physic, and consisting of books i. ii. iii. v. vi. vii. viii., which give the history of former systems and the ground work of his own. The second treatise is contained in book xi., which, after a short sketch of the nature of substance in general, ends in a dissertation upon the nature of God. Books ix. (on Unity) and xii. xiii. (on the Pythagorean and Platonic systems of numbers and ideas), appear to have been intended for the first treatise, but they remain as mere materials for a magmim opus which was never achieved. We see, then, out of what disjecta membra the Metaphysics of Aristotle, as they stand in our editions, are composed. How far the making up of them into their present form is due to Eudemus and the earlier Peripa tetics, how far to the editorial hand of Andronicus, we can not tell. Among the many-sided merits of Aristotle must be mentioned the example set by him of making the history of opinion on each subject the prelude to a scientific considera tion of the subject itelf. In the first book of his Meta physics he sketches the leading doctrines of his predecessors on the first principles of existence. He thus becomes the father of the history of philosophy, a study which has been taken up anew and much developed during the pre sent century. His brief and masterly sketch is, however, open to the charge of not doing sufficient justice to the different points of view of former philosophers. And his polemic against Plato s doctrine of Ideas, which is several times repeated 10 in his extant writings, has the appearance of captiousness, and of misrepresenting the 11 doctrine which it impugns. Aristotle himself never discarded idealism. He declared that universals, and the truths apprehensibln by the highest reason, were " by nature more known" 18 than individual concrete phenomena, and the facts appre hended by sense. But yet he had the strongest bias to wards physical research and empirical observation. A modern physical philosopher might have been content to follow out his own special inquiries without seeking a general scheme for the universe. But Aristotle had to form a theory of the whole, leaving scope, afterwards, for the separate physical sciences. The idealism of Plato did not do this ; it left no place for matter, motion, or change ; when followed out it reduced all but the Ideas to the category of the non-existent. Aristotle, to rescue all nature from theoretical annihilation, introduced a term between the existent and the non-existent, namely, the " potential " (SiW^i?). On the one hand, the potential does not exist, for as yet it has no qualities ; on the other hand, it does exist, for some change brings the " actual " 10 See a critical examination of all the places in Zeller s Platonische Sludien (Tubingen, 1839), pp. 199-300. 11 Plato by no means consistently maintained the doctrine of Ideas, as commonly attributed to him. In the Parmenides he himself draws out the objections which may be urged against the system. Ar.<i, wonderful to relate, Aristotle uses some of these very objections in attacking Plato !
12 Topics, vi. 4, 1-10, and see note 13, p. 514.