ONE:
TWO:Jeff! warned Sandy.That Plato put forward the ethical theory of the Protagoras in perfect good faith cannot, we think, be doubted; although in other writings he has repudiated hedonism with contemptuous aversion; and it seems equally evident that this was his earliest contribution to positive thought. Of all his theories it is the simplest and most Socratic; for Socrates, in endeavouring to reclaim the foolish or vicious, often spoke as if self-interest was the paramount principle of human nature; although, had his assumption been formulated as an abstract proposition, he too might have shrunk from it with something of the uneasiness attributed to Protagoras. And from internal evidence of another description we have reason to think that the Dialogue in question is a comparatively juvenile production, remembering always that the period of youth was much more189 protracted among the Greeks than among ourselves. One almost seems to recognise the hand of a boy just out of college, who delights in drawing caricatures of his teachers; and who, while he looks down on classical scholarship in comparison with more living and practical topics, is not sorry to show that he can discuss a difficult passage from Simonides better than the professors themselves.
ONE:There is, however, a principle in hydraulic machinery that must be taken into account, in comparing it with positively geared mechanism, which often leads to loss of power that in many cases will overbalance any gain derived from the peculiar action of hydraulic apparatus. I allude to the loss of power incident to dealing with an inelastic medium, where the amount of force expended is constant, regardless of the resistance offered. A hydraulic crane, for instance, consumes power in proportion to its movements, and not as the amount of duty performed; it takes the same quantity of water to fill the cylinders of such cranes, whether the water exert much or little force in moving the pistons. The difference between employing elastic mediums like air and steam, and an inelastic medium like water, for transmitting force in performing irregular duty, has been already alluded to, and forms a very interesting study for a student in mechanics, leading, as it does, to the solution of many problems concerning the use and effect of power.His analysis of individuality was the first step in this direction. We have seen that he treats definition as a process of gradual specification, beginning with the most general notions, and working down by successive differentiations to the most particular. Now, the completed conception is itself the integration of all these differences, the bond of union holding them together. Turning to an antithetical order of ideas, to the material substance of which bodies are composed, and its various transformations, we find him working out the same vein of thought. According to the Aristotelian chemistry, an ultimate indeterminate unknowable something clothes itself with one or other of the opposing attributes, dry and moist, hot and cold; and when two of these are combined, manifests itself to our senses as one of the four elements. The elements combine in a particular manner to form homogeneous animal tissues, and these again are united into heterogeneous organs, which together constitute the living body. Here, then, we have two analogous series of specificationsone conceptual and leading down from the abstract to the concrete, the other physical, and leading up from the vague, the simple, and the homogeneous, to the definite, the complex, and the heterogeneous. Aristotle embraces both processes under a single comprehensive generalisation. He describes each of them as the continuous conversion of a346 possibility into an actuality. For the sake of greater clearness, let us take the liberty of substituting modern scientific terms for his cumbrous and obsolete classifications. We shall then say that the general notion, living thing, contains under it the two less general notionsplant and animal. If we only know of any given object that it has life, there is implied the possibility of its being either the one or the other, but not both together. On determining it to be (say) an animal, we actualise one of the possibilities. But the actualisation is only relative, and immediately becomes the possibility of being either a vertebrate or an invertebrate animal. The actuality vertebrate becomes the possibility of viviparous or oviparous, and so on through successive differentiations until we come (say) to a man. Now let us begin at the material end. Here are a mass of molecules, which, in their actual state are only carbon, nitrogen, and so forth. But they are potential starch, gluten, water, or any other article of food that might be named; for under favourable conditions they will combine to form it. Once actualised as such, they are possible blood-cells; these are possible tissues; these, again, possible organs, and lastly we come to the consensus of vital functions, which is a man. What the raw material is to the finished product, that are the parts to the entire organism, the elements to the compound, the genus to the species, and such in its very widest sense is potency to realisation, δ?ναμι? to ?ντελ?χεια, throughout the universe of growth and decay.246
TWO:Another method by which Aristotle strove to overcome the antithesis between life as a mechanical arrangement and life as a metaphysical conception, was the newly created study of comparative anatomy. The variations in structure and function which accompany variations in the environment, though statically and not dynamically conceived, bring us very near to the truth that biological phenomena are subject to the same general laws of causation as all other phenomena; and it is this truth which, in the science of life, corresponds to the identification of terrestrial with celestial physics in the science of general mechanics. Vitality is not an individualised principle stationed in the heart and serving only to balance opposite forces against one another; but it is diffused through all the tissues, and bestows on them that extraordinary plasticity which responds to the actions of the environment by spontaneous variations capable of being summed up in any direction, and so creating entirely new organic forms without the intervention of any supernatural agency.
