or more causes which have been reached necessarily limit and condition one another. Whence and why are they thus bounded and associated? The question cannot be evaded. Reason demands an answer to it, and no answer can be found in the several finite and co-ordinate causes themselves; it must be found in a single higher cause on which they are dependent. It is only by reaching unity that we can get above the limits and conditions which are conclusive evidences of dependence. Hence every form of dualism must be rejected as a theory of existence. Only a monistic philosophy can be a true philosophy. But theism, say materialists, is essentially dualistic. It traces the diversity of phenomena in the universe not to one cause, but to two causes. It refers some things to mind, and other things to matter, and maintains that matter and mind are substantially distinct. It leaves us with two principles, and by so doing virtually reduces even the one which it pronounces infinite to something finite, while it renders it impossible for us to conceive of the connection between matter and mind otherwise than as arbitrary. Materialism, on the other hand, is monism. It explains the whole world in terms of matter. It resolves everything in nature-order, organisation, life, sensation, thought, poetry, religion, history-into combinations and motions of matter. It exhibits the universe as a perfectly

homogeneous and coherent system naturally evolved out of a single primary existence. It thus satisfies the demands of philosophy or rational theory for unity. Idealism, it is true, sets up rival pretensions. It professes to start with the selfidentity or absolute unity of thought, and to explain matter as a stage in the development or as a phase of the manifestation of thought. But are not its claims obviously less satisfactory? We know nothing of ideas or thoughts except as states of human consciousness, as affections or products of that in ourselves which we call mind. They are special phenomena in the life or experience of men, and men are themselves only a species of natural existences-a class of animalsapparently the last evolved in the terrestrial sphere of things. Man is included in the universe, and ideas are included in man. Reason consequently requires us to seek the explanation of man and ideas in what is common and primary in the universe-matter and motion. To attempt to explain what is ancient by what is recent, the general by the particular, the macrocosm by the microcosm, universal existence by the modifications of highly specialised organisations, is a monstrous vσrepov πроτероν, a manifest violation of the laws of scientific method. Thought, which is independent of human consciousness, can only be affirmed to exist by an arbitrary act of the individual mind,

and is no real principle, but a mystical assumption; thought, which is dependent on human consciousness, can no more be the unity which accounts for the universe, than the characteristic features of the leaves of a particular kind of tree can be the sole and adequate explanation of the entire vegetable kingdom.

Further, materialism claims to be the only theory which satisfactorily shows that all things have come to be what they are in a truly natural manner. When describing the evolution of the universe from unity to multiplicity, it appeals to no arbitrary or imaginary factor, no principle which is supernatural, no process which transcends or contravenes science. It represents the universe as a self-consistent and perfect system, in which everything that happens follows necessarily from the powers inherent in the system itself. Theism, on the contrary, supposes that the universe in itself is incoherent and imperfect, and that the explanation of many things in it must be sought for out of itself. It conceives of the matter of the world as created; of its powers as derived; of its order as contrived; and of certain events and existences comprehended in it as produced by special acts of Divine interposition. Such a view, say materialists, is essentially anti-scientific. It implicitly denies not only that the world is a scientific unity, but that its phenomena are expli

cable in a natural manner, whereas the chief end of science is to show that the world is a systematic unity, and that all its phenomena can be naturally explained. Idealism may, indeed, be here again opposed to materialism. Idealism also professes to account in a strictly natural manner for all that is explicable. It starts from the unity of a single principle, and has recourse only to immanent processes, excluding entirely acts of supernatural interference. Idealism, however, it will be replied, breaks down the moment it is brought into real contact with external nature. The supposition of its truth implies that the various operations of the physical world can be explained by the laws of an impersonal and unconscious dialectic; that mechanical, chemical, and organic processes are essentially notional or rational. But this is a hypothesis which physical science will not allow us to entertain. The attempt to interpret mechanical, chemical, and organic facts in connection with it has always resulted either in caricaturing or contradicting the explanations of them given by physical science. In other words, it has invariably led to dualism of the worst kind,—the dualism which consists in irreconcilable antagonism between philosophy and science. Hegelianism supplies us with a striking illustration and proof. Hegel and his followers saw more clearly than the idealists of any other school had done that it was

incumbent upon them to show that nature was a system of which the processes were the stages and expressions of an immanent logical evolution, and they laboured strenuously and ingeniously at the task. What was the result? A so-called philosophy of nature, which physical science is forced to condemn as a gigantic swindle. In the Hegelian philosophy of nature, idealism made evident its scientific bankruptcy. It is very different with materialism, which accepts and incorporates the whole of physical science without alteration or perversion; which founds upon the results of physical research, and tries to extend its principles and apply its methods as far as is legitimately possible.

A closely connected excellence claimed by materialism is that of being the most intelligible of systems. It is maintained that we never truly understand a fact or process of which we cannot form a distinct and precise image or picture. Whenever a thing is scientifically explained, the mind is enabled to form to itself a definite and clear conception of how that thing came to be what it is. But pseudo-explanations—as, for example, those given of natural phenomena by ancient and scholastic philosophy—are invariably vague and mystical. Can anything, however, except matter and material processes, be definitely and minutely imaged? Can anything else be estimated with quantitative accuracy? Can there be