The constituents of mind do not lie side by side tranquilly co-existent, like the sheep beside the herbage on which it browses. Their existence is maintained in an inward movement, by which, while they differentiate themselves, they still keep up an identity. In our investigations we cannot begin with what is to be defined. The botanist, if he is to give us a science of the plant, must begin with something whose indwelling aim it is to be itself and to realise its own possibility. He must begin with what is not the plant, and end with what is; begin, let us say, with the germ which has the tendency to pass into the plant. The speculative science of biology begins with a cell, and builds these cells up into the tissues and structures out of which vegetables and animals are constituted. The object of the science appears as the result of the scientific process: or, _a science is the ideal construction of its object_. As in these cases, so in the case of thought. We must see it grow up from its simplest element, from the bare point of being, the mere speck of being which, if actually no better than nothing, is yet a germ which in the air of thought will grow and spread; and see it appear as a result due to the ingrowing and outgrowing union of many elements, none of which satisfies by itself, but leads onward from abstractions to the meeting of abstractions in what is more and more concrete. The will and conscience, understanding and reason, of man are not matter-of-fact units to be picked up and examined. You must, first of all, make sure what you have in hand: and to be sure of that is to see that the mind is the necessary outcome of a course of development. The mind is not an immediate _datum,_ with nothing behind it, coming upon the field of mental vision with a divinely-bestowed array of faculties; but a mediated unity, i. e. a unity which has grown up through a complex interaction of forces, and which lives in differences through comprehending and reconciling antagonisms.