of definition. Tastes of mixed or intermediate character may exist almost ad infinitum, and, what is still more troublesome, the tastes clearly united within one class may differ more or less from each other, without our being able to arrange them in subordinate genera and species. The same remarks may be made concerning the classification of odours, which may be roughly grouped according to the arrangement of Linnæus as, Aromatic, Fragrant, Ambrosiac, Alliaceous, Fetid, Virulent, Nauseous. Within each of these vague classes, however, there would be infinite shades of variety, and each class would graduate probably into each other class. The varieties of odour which can be discriminated by an acute olfactory organ are almost infinite; every rock, stone, plant, or animal has some slight odour, and it is well known that dogs, or even blind human beings, can discriminate persons by a slight distinctive odour which usually passes unnoticed.

Nearly similar remarks may be made concerning the higher feelings of the human mind, usually called emotions. We know what is anger, grief, fear, hatred, love; and many systems for classifying these feelings have been proposed at one time or another. They may be roughly distinguished according as they are pleasurable or painful, prospective or retrospective, selfish or sympathetic, active or passive, and possibly in many other ways, but each mode of arrangement will be indefinite and unsatisfactory when followed into details. As a general rule, the emotional state of the mind at any moment will be neither pure anger nor pure fear, nor any one pure feeling, but an indefinite and complex aggregate of feelings. It may be that the state of mind is really a sum of several distinct modes of agitation, just as a mixed colour is the sum of the several distinct rays of the spectrum. In this case there may be more hope of some method of analysis being successfully applied at some future time. But it may

be found that states of mind really graduate into each other, so that rigorous classification would prove to be hopeless.

We

A little reflection will show that there are whole worlds of existences which in like manner are incapable of logical analysis and classification. One friend may be able to single out and identify another friend by his countenance among a million other countenances. Faces are capable of infinite discrimination, but who shall classify and define them, or say by what particular shades of feature he does judge. There are of course certain distinct types of face, but each type is connected with each other type by infinite intermediate specimens. may classify melodies according to the major or minor key, the character of the time, and some other distinct points; but every melody has independently of such circumstances its own distinctive character and effect upon the mind. Similar remarks might be made concerning a multitude of other circumstances. We can detect differences between the styles of literary, musical, or artistic compositions. We can even in some cases assign a picture to its painter, or a symphony to its composer, by a subtle feeling of resemblances or differences of character and expression, which may be felt, but cannot be described.

Finally, it is apparent that in human character there is unfathomable and inexhaustible diversity. Every mind is more or less like every other mind; there is always a basis of similarity, but there is a superstructure of feelings, impulses, or motives which is distinctive for each person. We can often, indeed, predict the general character of the feelings or actions which will be produced in a given individual well known to us, by a given external event, but we also know that we are often inexplicably at fault in all our inferences. No one can safely generalize upon the subtle variations of temper and emotion which may

arise even in a person of ordinary character. As human knowledge and civilization progress, these characteristic differences tend to develop and multiply themselves rather than decrease. Character grows more evidently manysided. Two well educated Englishmen are far better distinguished from each other than two common labourers, and these are better distinguished, again, than two Australian aborigines. Thus the complexities of existing phenomena develop themselves more rapidly than scientific method can overtake them. In spite of all the boasted powers of science, we cannot really apply method to those existences, namely, our own minds and characters, which are more important to us than all the stars and nebulæ.

BOOK VI.

CHAPTER XXXI.

REFLECTIONS ON THE RESULTS AND LIMITS OF

SCIENTIFIC METHOD.

BEFORE Concluding a work on the Principles of Science, it will not be inappropriate to add some remarks upon the limits and ultimate bearings of the knowledge which we may acquire by the constant employment of scientific method. All science consists, it has several times been stated, in the detection of identities and uniformities in the action of natural agents. The purpose of inductive inquiry is to ascertain the apparent existence of necessary connexion between causes and effects, the establishment of natural laws. Now so far as we thus learn the invariable course of nature, the future becomes the necessary sequel of the present, and we are brought beneath the sway of powers with which nothing can interfere.

By degrees it is found, too, that the chemistry of organized substances is not widely separated from, but is rather continuous with, that of earth and stones. Life itself seems to be nothing but a special form of that energy which is manifested in heat and electricity and mechanical force. The time may come, it almost seems,

when the tender mechanism of the brain will be traced out, and every thought reduced to the expenditure of a determinate weight of nitrogen and phosphorus. No apparent limit exists to the success of scientific method in weighing and measuring, and reducing beneath the sway of law, the phenomena both of matter and of mind. And if mental phenomena be thus capable of treatment by the balance and the micrometer, can we any longer hold that mind is distinct from matter? Must not the same inexorable reign of law, which is apparent in the motions of brute matter, be extended to the most subtle feelings of the human heart? Are not plants and animals and ultimately man himself, merely crystals, as it were, of a complicated form? If so, our boasted Free Will becomes a delusion, Moral Responsibility a fiction, Spirit a mere name for the more curious manifestations of material energy. All that happens, whether right or wrong, pleasurable or painful, is but the outcome of the necessary relations of time and space and force, and of the laws of matter emerging from them, which are fixed in the very nature of things.

Materialism seems, then, to be the coming religion, and resignation to the nonenity of human will the only duty. Such may not generally be the reflections of men of science, but I believe that we may thus describe the secret feelings of fear which the constant advance of scientific investigation excites in the minds of many who view it from a distance. Is science, then, essentially atheistic and materialistic in its tendency? Does the uniform action of material causes, which we learn with an ever increasing approach to certainty, preclude the hypothesis of an intelligent and benevolent Creator, who has not only designed the existing universe, but who still retains the power to alter its course from time to time?