BIOLOGY. mere illusions : he who, in fear of these evil consequences, dreads the reduction of human ■conduct to mechanics — may seek refuge in some corner of tlie realm of biologj' in hope that, since it has not yet been invaded by the inquisitive man of science, perhajis it never may be; but nothing could be less judicious, in view of the present condition and prospects of biology, than thus to take refuge under the shelter of ig- norance. He who believes that evil consequences will follow the prevalence in biology of mechani- cal conceptions, is not the only advocate of opinions that the progress of biological science may, in time, render untenable. It hapijens, odd- ly enough, that certain highly esteemed thinkers, who are among the most enthusiastic advocates of a mechanical interpretation of all the facts of biology', and who chiim to sjjcak with authority upon the philosophical meaning of physical sci- ence, are also the advocates and defendaats of a system of philosophy that no one could, in consistency, accept, or even consider with favor, if all the facts of biology were to be fonnulated in terms of matter and motion ; because this system of philosophy connnits its disciples to the belief that there is a 'chasm' which is 'intel- lectually impassable' between the facts of physics 4ind the facts of consciou.sness. Herbert Spencer, for example, is inevitably led, by the premises of his system of philosophy, to believe and to teach that mind "is something without any kin- ship with other things; and from the sciences which discover, by introspection, the laws of this something there is no passar/e by transitional steps to the sciences which discover the laws of these other things." As we are also informed by this philosopher that, while the volume of the synthetic philosophy which is to deal with the evolution of living beings from inorganic matter is not yet written, he has handled the subject of later volumes as if the reader had this missing volume in his mind; the cautious biologist, who wishes to hold no opinion that he could not still maintain even if all the facts of biology were reducc<l to mechanics, may be somewhat puzzled, in lack of this missing volume, as to the frame of mind ill which he is to approach the works of the author of the Principles of Biology. Turning now, for the present, from the opinion that hiologj' is the physics and chemistrs' 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 an indeiiendent realm of sci- ence: for there is nuich to l)e said in support of the o|)inion that, even if all t)iological 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 i)ainting of a picture. While both these handicrafts consist in the move- ment of matter according to the laws of mechan- 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 tlie horseshoe and the picture show that, because blacksmithing and art are both to be reduced to physics and chemi.stry, they are fundamentally identical. Even if the day were to come when all this had been accomplished, physics would still remain 87 BIOLOGY. physics, and blacksmithing and art would still be what they are. If, like I'aley, I kick a stone, I may change its position, raise its temperature, and bring about other ciianges which 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 are 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 sliort 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 efteet 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., are racial char- 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 bi'have : 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 moi-e 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 or 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 be accompanied by a dog. this third party may modify the result without any share in the assault. What a difference lietween a kick against a dog and one against a stone! In one case tho conditions niay be stated in few words, and the result may be computed; while in the other, a book would not sudice 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 b(; that all the conditions which modify the result are embodied in the structure of tho dog, for we have no reason to seek them anywhere else. I see no reason to doubt that, if the do'f's body could he preserved without change, it might, .some day in the remote future, he studied by some naturalist who would he able to tell what conduct would have followed the kick with all the certainty with which one may foresee the ell'cct of an oi)encd valve in a steam-engine;
