Turning now, for the present, from the opinion that biology is the physies and chemistry of liv ing matter. let us consider the opinion that its objects and aims and methods are so foreign to the physics and chemistry of our day that we must regard it as au independent realm of sci ence; fur there is much to be said in support of the opinion that, even if till bitdogical facts were to be reduced to mechanics and formulated in terms of matter and motion, biology would still remain an independent science, as distinct from physics and chemistry as, for example, the shoe ing of a horse is from the painting of a picture. While both these handicrafts consist in the move ment of matter according to the laws of meehan ics, this fact, assuredly. affords no satisfactory account of either of them ; nor would the reduc tion to mechanics- of the desires and motives and voluntary acts and rational and emotional pro cesses which find expression in the horseshoe and the picture show that, because blacksmithing and art are both to be reduced to physics and chemktry, they are fundamentally identical. Even if the day were to come when all this had been accomplished, physics would still remain physics, and blacksmithing and art would still be what they are.
If, like Paley, I kick a stone, I may change its position, raise its temperature, and bring about other changes wh;en might have been predicted from a few simple data. What happens if, in stead of a stone, it is a dog that I kick? In addition to certain changes that arc obviously mechanical, like those in the stone, I start a new set of changes that could never be predicted from the study of the kick alone. But note this remarkable fact: show me the dog, and I may be able to tell you what he will do. If he have short hair, a pink skin, a big occipital erest,great cheek-muscles. a long mandibular bone, a short nose with little pigment, small red eyes, and short, crooked legs, he will not act like a curly haired dog with long silky ears, large dark eyes, a long, black, pointed nose, a bushy tail, and long legs with large feet.
What has the color of the dog's nose or the size of his feet to do with the effect of the kick? Obviously, nothing at all; but the changes in the dog which follow the kick are not its mechanical equivalent, for they might follow an unsuccessful attempt to kick just as they follow' an actual blow. The color of his eyes, etc., arc racial chair acteristics which show what his ancestry has been ; how his parents and other ancestors have behaved under similar assaults. With this scientific knowledge of dogs we may conjecture, with some confidence, how this one will behave; but in order to compute his conduct with anything like accuracy, we must have still more information.
If his master habitually beats and bullies him. he will not act like a dog brought up with more discretion. If he is young, and has not learned independence, and self-reliance, and distrust of strangers, he will not act like an older and wiser dog; and if eyes and limbs and teeth are failing, his conduct will be still different. If the kick awakes him from sleep, he will not act like a dog disturbed while eating; nor will a lost dog, op pressed by a sense of friendlessness, act like one whose master is near; nor one assaulted at home, like one on forbidden ground; nor one attacked while in the discharge of duty, like one detected in theft nr in forbidden pleasure. The attitude of the assailant, or even such little things as the size of the pupil of his eye. or the contraction of one or another facial muscle. may tell the dog what emotions accompany the kick; and if I myself he accompanied by a dog, this third party may modify the result without any shine in the assault.
What a difference between a kick against a dog and one against a stone! In one case the conditions may he stated in few word, and the result may be computed: while in the other. book would not suffice for the statement of all the facts, and the best science of our day is powerless to formulate the result in terms of mechanics.
It may be that all the conditions which modify the result are embodied in the structure of the dog, for we have no reason to seek them anywhere I see no reason to doubt that, if the dog's body could be preserved without change, it might, sonic day hi the remote future, he studied by some naturalist who would be able to tell what eonduet would have followed the kick with all the certainty with which one may foresee the effect of an opened valve in a steam-engine; but we have not yet noted the most essential characteristics of the dog's actions. They are significant. They have a meaning. They stand in judicious adjustment to the canine world. Whether he shuts his eyes, throws back his ears, and, straightening his tail, plants his teeth in my leg. or crouches at any feet with his muscles re laxed, his ears pendant, and his tail trailing, or, putting his tail between his legs, runs away howl ing. the reason for his conduct is not the me chanical impact of the blow, nor the pain which it causes, but the importance of escape from the further injury which may follow. The means he adopts are those which have been favorable to this result in the past history of dogs.