Let it not be supposed that I am denying the existence, and the richly diversified existence, of the external world. We are fully justified, I think, in believing that, corresponding to the diversity of mental symbolism, there is a rich diversity of external existence. But its nature I hold that we can never know. The objects that we see are the joint products of two factors--the external existence and the percipient mind. We cannot eliminate the latter factor so as to see what the external factor is like without it. Those who, like Professor Mivart,[FS] say that we can eliminate the percipient factor, and that the external world without it is just the same as it is with it, are content to reduce the human mind, in the matter of perception, to the level of a piece of looking-glass. There are some people who seek to get behind phenomena by an appeal to evolution. It will not do nowadays, they say, to make the human mind a starting-point in these considerations; for the human mind is the product of evolution, and throughout that evolution has been step by step moulded to the external world. The external world has, therefore, the prior existence, and to it our perceptions have to conform. All this is quite true; but it is beside the point. Mind has, throughout the process of evolution, been moulded to the external world; our perceptions do conform to outside existences. But they conform, not in exact resemblance, but in mental symbolism. They do not copy, but they correspond to, external existences. It is just because, throughout the long ages of evolution, mind has lived and worked in this symbolic world that common sense is unable to shake off the conviction that this is the only possible world, and exists as such independently of mental processes. The world of phenomena _is_ the world in which we, as conscious beings, live and move. No one denies it. But it is none the less a symbolic world; none the less a world which mind has constructed in the sense that it is an inalienable factor in its being. Each of us, when we perceive an object, repeats and summarizes the constructive process which it has been the end of mental evolution to compass. Hence it is that, at the bidding of a simple impression, percepts or constructs take origin and shape in the mind. In taking possession of this faculty in the early years of life, we are entering upon a rich ancestral heritage. But if what I have been urging has truth, what we call objects are human constructs, and cannot by any manipulation be converted into anything else.