The philosophical hypothesis known as monism regards the molecular change, not as the antecedent of a conscious state, but as its concomitant. That which from a physical and physiological point of view is a complex molecular disturbance is, at the same time, from a psychological point of view, a state of consciousness. The two are different aspects of one natural occurrence. Why such an occurrence should have two so different aspects we have not the faintest idea; but here we are not one whit worse off than we were before. The hypothesis does, however, help us to get over our difficulty. An essential feature of Huxley’s contention is that the physical and physiological chain of causation is complete in itself, which may be granted; and further, that if consciousness does arise it is merely an adjunct without influence on the sequence of events--what is influential is the molecular disturbance, not the consciousness which accompanies it. But according to monism the state of consciousness actually is that very same something which the physiologist calls, in the language of physics, a molecular disturbance. And in saying that consciousness influences behaviour one who accepts this hypothesis is merely avoiding a cumbrous form of circumlocution. He puts it in this way instead of saying that the nerve-changes in the cerebral hemispheres, or elsewhere, which from a psychological point of view _are_ a conscious situation, influence and determine the course of behaviour. But from this point of view it is absurd to say that the consciousness is merely an adjunct--absurd to say that were there no conscious situation the neural situation would remain unchanged. They are the very same thing from different points of view; and to say there is no influential conscious situation is simply equivalent to saying that there is not this determining neural situation. However we explain the fact, there are few who hesitate to accept it for the purposes of scientific explanation. The conscious situation, having no doubt for the physiologist a neural aspect if he could only get at it as a whole, does practically determine the behaviour of the animal which has gained the requisite experience. If we accept the fact, we may pass on to its importance in securing the biological end of race preservation. It is a commonplace of evolutionary doctrine that, other things being equal, those races will survive, in the constituent members of which intelligent behaviour enables them to deal most effectually with an environment of increasing complexity. And it is a matter of familiar observation that such behaviour is closely connected with delicacy and refinement of development in those senses which take the lead in cognitional process, and with rapidity and precision in the motor co-ordination through which prompt and skilful advantage is taken of the situation which has, through experience, acquired meaning.