This concrete notion of a spirit which excludes nothing from itself gives concreteness to the Christian conception of physical discipline. For it aims to turn the body into an obedient tool of the will, not however of that will which renounces the world, but of that will which turns to the world as to the field where its battles are fought and won; to the world which it transforms by its work, constantly re-creating it, now modifying one part and now another, but always acting on the entire system, and renewing it as a whole in the intimate organic connection and interdependence of these parts; to the world which forever confronts it in a rebellious and challenging attitude, and which it laboriously subdues and turns into a mirror of its own becoming. Modern idealism and ancient naturalism both emphasise, though for opposite motives, the importance of a positive education in distinction to the negative discipline inculcated by mediæval asceticism. We said that to-day we develop the body because the body is spirit. This proposition runs counter to common sense. But common sense as such cannot be respected by the thinker unless he first transforms its content. Our body, we must remember, is not one body out of many. If it were actually mixed with and lost in the multitude of material things which surround it, we could no longer speak of any bodies. For all bodies, as psychologists say, are perceived in so far as they modify ours and are somehow related to it. Or to put it in a different and perhaps better way, all other bodies, which we possess as contents of our experience, form a system, a circle, which has its centre; and this centre is our body. These first of all occupy space, but a space which no one of us can think of or intuit otherwise than as a radiating infinity, the centre of which we occupy with our body. So that before we can speak of bodies, we must first cognise our own. It is the foundation and groundwork of all bodies. Justly, therefore, the immanent sense, profound and continuous, which we have of our body, and whose modifications constitute all our particular sensations, was called the _fundamental sentiment_ by our Italian philosopher Rosmini. For our body is ours only in so far as we feel it; and we feel it, at first, confusedly or rather indistinctly, without discerning any differentiated part. We feel it as the limit, the other, the opposite, the object of our consciousness, which, were it not conscious of something (of itself as of something), would not be consciousness, would not realise itself. And it realises itself, in the first place, as consciousness of this object which is the body. Accurately, therefore, was the body defined by Spinoza as _objectum mentis_, as object of consciousness. Objectless consciousness is not consciousness; and it is likewise obvious that the object of consciousness cannot be such without consciousness.