is this community of nature, that for some time past many naturalists have wished to establish for these lowest types a sub-kingdom, intermediate between the animal and the vegetal: the reason against this course being, however, that the difficulty crops up afresh at any assumed place where this intermediate sub-kingdom may be supposed to join the other two. Thus the assumption on which Mr Martineau proceeds is diametrically opposed to the conviction of naturalists in general." -Cont. Rev., June 1872.

There remains the barrier of mind or consciousness. The materialist maintains that science proves that matter is, in this case, also an adequate principle of explanation. All the powers of the human mind may be traced to roots in the lower animals. The life of the body and its functions are manifestations of the same generic principle as the so-called life of the soul and its functions. There is only a difference of degree between the highest mental and the lowest vital faculties. There is no absolute break or distinction, but, on the contrary, a continuous progression along the entire psychological line which runs from the protogenes and protamaba to Plato and Shakespeare, and yet in the two former the motions, which are the evidences of their animality, are scarcely, if at all, distinguishable from the contractions and expansions of certain colloidal

substances. The doctrines of the correlation of forces and of development are as applicable to the explanation of mind as of life. Mind is force, the highest development of force, the force which is accumulated in the brain and nerves; and mental force is as exactly correlated with vital and with physical force as these are with each other. It may be proved by a variety of scientific considerations that all forces come under the same generalisation. Motion, heat, and light, may be transformed into sensation, emotion, and thought; and these may be reconverted into motion, heat, and light. The theory of development has been employed with success by a host of investigators in the elucidation of all kinds of mental phenomena. The result has been to show that the phenomena peculiar to human psychology may be resolved into simpler states, and that these may be traced backwards and downwards until the primordial properties of matter are reached.

The argument for materialism may now, perhaps, be fitly concluded in the words of Professor Huxley: "I take it to be demonstrable that it is utterly impossible to prove that anything whatever may not be the effect of a material and necessary cause, and that human logic is equally incompetent to prove that any act is really spontaneous. A really spontaneous act is one which, by the assumption, has no cause; and the attempt.

to prove such a negative as this, is, on the very face of the matter, absurd. And while it is thus a philosophical impossibility to demonstrate that any given phenomenon is not the effect of a material cause, any one who is acquainted with the history of science will admit that its progress has, in all ages, meant, and now more than ever means, the extension of the province of what we call matter and causation, and the concomitant gradual banishment from all regions of human thought of what we call spirit and spontaneity. And as surely as every future grows out of the past and present, so will the physiology of the future gradually extend the realm of matter and law until it is coextensive with knowledge, with feeling, and with action. The consciousness of this great truth. weighs like a nightmare, I believe, upon many of the best minds of these days. They watch what they conceive to be the progress of materialism, in such fear and powerless anger as a savage feels when, during an eclipse, the great shadow creeps over the face of the sun. The advancing tide of matter threatens to drown their souls; the tightening grasp of law impedes their freedom; they are alarmed lest man's moral nature be debased by the increase of his wisdom." 1

1 See Appendix XV.

II.

A general view of the argument in favour of materialism has now been laid before you. My next duty is to examine whether or not the reasoning which it includes and involves is valid.

Is it true, then, I ask, that materialism satisfies the legitimate demands of the reason for unity? I grant that reason, when in quest of an ultimate explanation of things, imperatively demands unity, and that only a monistic theory of the universe can deserve the name of a philosophy. While aware that the desire for unity has given rise to countless aberrations, and that it needs to be carefully watched lest it create factitious unities when it fails to find real unities, I yet unhesitatingly acknowledge that it originates in, and is the expression of, the very constitution of rational thought, which can never regard a number of co-ordinate causes as other than a group of secondary causes. But the question is, Is materialism monism? or, in other words, Is matter one? I answer, No. Matter cannot possibly be conceived of as properly one. Materialism is necessarily multitudinism, and as such must inevitably be pronounced an essentially unphilosophical and irrational hypothesis.

The world presented to us by the senses and

immediate consciousness is certainly not one, and is held by nobody to be one. It is a vast complex of objects, agencies, and conditions-stars, stones, plants, animals, light, heat, electricity, thoughts, feelings, volitions. Its contents may have a unity imparted to them by generalisation, but merely a unity which is given to them from without and for a purpose, a unity which depends on the point of view from which things are considered. There may be any number of such unities; there may be even more of them than there are things. Real unity cannot be thus reached. Nor is it thus but by analysis that materialists seek it. Things may be resolved into their elements; compounds may be reduced to simples. This process of analysis might conceivably take us far towards a sort of unity in a strictly scientific manner. I cannot indeed admit its sufficiency to take us quite even to the unity of a single physical element, for no such element, no single entirely uncompounded element, can ever produce another. Two physical elements may produce a third, but no one element can ever produce anything. It must for ever remain itself. There is, however, no obvious reason why analysis should not have proved that there are only two, or at least a very few, physical elements, out of which have been formed by successive combinations all material substances, the socalled elements included. But it has in reality.