The spirit is free only if infinite. It cannot have any obstructing barrier in its path. It can be conceived as freedom only after it has overcome dualism, and when in nature itself and in the body we see the effect of the activity of the spirit. It has no need therefore of walls within which it might feel the necessity of cloistering itself in the effort to renounce the outer world. This is not the way to conquer freedom. A liberty won under such conditions would always be insecure, constantly threatened, always beleaguered, and therefore a mere shadow of freedom. The spirit, if it is free, that is, if it is spirit, must be conterminous with thought, it must extend its sway as far as there is any sign of life to the last point where a vestige of being can be revealed to it. Nothing thinkable can be external to it. Whatever presents itself to it, whether in the garb of an enemy or under the cloak of friendship, can only be one of its creatures, which it has placed at its own side, or in front of itself, or against itself. This new pedagogical and philosophical view, first disclosed to Humanism, then enlightened by the genius of the Italian Renaissance, appears now to us in the full light of modern thought. Superficially it might seem identical with the classical and naturalistic outlook. In reality, however, it has made its way back to it only in order to confirm and integrate the concept of Christian spiritualism and to bring out its truth. Greek athletics is the training of the body as an end in itself: it surely serves the cause of the spirit, but only in so far as the spirit is grafted on the trunk of the physical personality, and to the extent that it is able to absorb all its vital sap, thereby subjecting itself to generation and decay, the common destiny of all natural beings. The physical culture of the ancients is spiritual discipline, only to the extent that for them the mind too is essentially body. Modern physical education, at least from the time of Vittorino da Feltre, is spiritual formation of the body: it is bodily training for the benefit of the spirit, just as the mediæval ascetic would have it; but of a spirit which does not intend to bury itself in abstract self-seclusion away from the existential world, of a spirit which passing beyond the cloister walls soars over the realm of nature, induing it and subduing it instrumentally to its ends and as a mirror of its will. So that for moderns, too, physical culture is spiritual education, but for the reason that to us the body itself is spirit. Our science is not merely a speculation of ultra-mundane truths, but rather a science of man and of man in the Universe, and therefore also of this nature which is dominated and spiritualised by becoming known, in the same way that every book that is read is spiritualised.