Page:Encyclopædia Britannica, Ninth Edition, v. 2.djvu/580

violated by all but the few first-rate works of fiction of the present day.

The Rhetoric, the Nicomachean Ethics, the Politics, and the fragment On Poetry, make up the sum of Aristotle's extant contributions to "practical" and "productive" philosophy. We have now to follow him into the "speculative" part of his system, consisting of a rich series of physical and physiological treatises. In this department the results arrived at 2200 years ago by Aristotle come into sharp contrast with the achievements of modern science up to the present day. Those who enter upon the comparison are apt to run into one of two extremes,^[1]—either to pass undiscriminating eulogies on Aristotle, and to credit him with impossible anticipations of future discovery, or to treat him with undue disparagement, as utterly false in method and puerile in his views of nature. It is only owing to Aristotle's real greatness that such a comparison could for a moment be made, for what, comparatively speaking, could be expected of a philosophy 2000 years old in respect of the sciences of observation and experiment, whose very essence consists in gradual advance from one new vantage point to another 1 To do personal justice to Aristotle, we must conceive, as a matter of fancy, what it would have been if he could have had one of the great modern discoveries imparted to him, the Copernican system, or the law of gravitation, or the circulation of the blood, or the analyses of air and water, or the conservation of energy; if he could have had any modern instrument of observation, such as the telescope or micro scope, or even the thermometer or barometer, placed in his hands. How swiftly would he have used such an advantage! what new and ramifying deductions and inductions he would have made! how radically he would have had modified many of his views! But all this was, of course, impossible. Physical knowledge was in its infancy; Aristotle could only start where his predecessors left off; he laid the foundation of many sciences, and wherever simple observation was adequate, as, for instance, in politics and in some parts of natural history, his achievements were complete and surprising. But for the greater realms of science he had no starting point and no appliances; he could only slightly modify the almost childlike views of the Greeks, and rest content with such unverified hypotheses^[2] as seemed to him best to cohere together, and to explain the nature of things. Thus, it is not to be wondered at that he considered the earth to be stationary and the centre of the world, with the seven planets (including as such the sun and moon) moving round it in oblique courses to the left, while the outer heaven or sphere of the stars composed not of perishable matter, but of divine ether he thought to move from left to right, with perfect and regular motion returning on itself, deriving its motion from the encompassing Godhead, -that essence which moves things, but is not moved itself. Such was, according to the belief of Aristotle, the framework of the universe; and the order^[3] of his physical treatises corresponds with the filling up of this framework. Of his method it may be said, in one word, that no one was ever more keen than he to make " fact " (TO on) the basis of every theory. It is not to be supposed for a moment that he attempted to explain nature by means of the syllogism. But, on the other hand, the art of experimenting, and the exact quantitative record of observations had not been developed. So Aristotle was often quite destitute of the appropriate " facts " for a particular inquiry, and sometimes deceived in the "facts" upon which he founded. And his training a? a dialectician was in some respects a disadvantage to him, as it led him to depend too much on the evidence of language in forming his theories of nature. The logical order of the physical treatises, and, probably to a great extent, the actual order of their composition, is as follows: 1st, The Physical Discourse, in eight books, forms an introduction to the entire subject. It is, as Hegel called it, "a Metaphysic of Physic." It treats of the Principles of Existence, Matter and Form, Nature, Motion, Time, Space, the Unmoved First Mover, and the Evermoved, i.e., the sphere of the outer heaven. 2c/, The treatise On the Heavens, in four books, naturally succeeds; and Aristotle, thus beginning with the periphery and divinest part of the universe, descends gradually to the region of the material and perishable. In so doing it becomes necessary to him to consider the causes of those changes, that passing into and out of existence, which had no place in the higher region. Therefore, 3d, the treatise On Generation and Destruction, in two books, gives us Aristotle's theory of the Hot and the Cold, and the Wet and the Dry, pairs of opposites, the first pair active, and the second pair passive, which by their combinations and mutual workings produce the four elements (Hot and Dry = Fire, Hot and Wet = Air, Cold and Dry = Earth, Cold and Wet = Water), and form the ground for all natural changes, kth, The Meteorologies, in three books, treat of the region of the planets, comets, and meteors, a region ever full of change and alteration. The fourth book of this treatise does not logically belong to it, for in it Aristotle develops his theory of two exhalations the steamy or wet, and the smoky or dry which, being imprisoned within the earth, produce, the former the metals, and the latter the rocks, and such other minerals as are incapable of being melted. This theory, which seems to be a dim fore shadowing of the doctrine of crystallisation, takes us out of the mid-air below the surface of the earth. It is, therefore, out of place; but almost everything in Aristotle must be looked upon as unfinished. 5th, The treatise On the Parts of Animals, in four books, leads the way to the investigation of organic life. It contains Aristotle's physiological distinction between homogeneous and unhomogeneous sub stances (6/ioto/Aep^ and dvo/xoto/zep-//), i.e., tissues and organs. This distinction, which is recognised still as perfectly valid, gives a scale of ascension from the inorganic to the organic world. First, Heat and Cold, &c., form the simple elements; out of the elements are formed the homogeneous substances or tissues; out of these are formed the organs, out of the organs the organised being. Asa principle of method, Aristotle lays it down^[4] that all which is common to the various species of living beings should be discussed before entering upon their specific differences. Therefore, dtth, the treatise On Soul follows next in order, which, as Spengel observes (see note 3), is not to be regarded as a work on psychology in the modern sense, but as a physiological treatise on the soul or vital principle common to all living beings. And next follow, 7th, the so-called Parva Naturalia, which form appendices to the three books On Soul, and treat physiologically of sense and sensation, youth and age, sleep and waking, and other phenomena attaching to life in general. 8th, The short essay On Locomotion of Animals shows how various organs in the

1. This subject may be studied in Mr Lewes's Aristotle, a Chapter from the History of Science, referred to in note 5, p. 511. Mr Lewes quotes some of the principal eulogies upon Aristotle's scientific merits. He himself affords an instance of the opposite extreme, being in many points too hard upon Aristotle.
2. There are some interesting remarks on the position of a Greek philosopher of the 4th century B.C. in relation to physical science, in Professor Jowett's Dialogues of Plato, translated (Oxford, 1871), vol. ii. p. 503, sqq. in the introduction to the "Timreus."
3. 3 See Dr Leonhard Spengel's paper on this subject, Abhandlungender Philos.-philol. Klasse der Bayerischen Akademie, 5th vol. 2d div. p. 142 (Munich, 1849).
4. De Part. Anim., i. 1, 4-7.