On a first survey, nothing appears more opposed than these two impulsions; one having for its object change, the other immutability, and yet it is these two notions that exhaust the notion of humanity, and a third _fundamental impulsion_, holding a medium between them, is quite inconceivable. How then shall we re-establish the unity of human nature, a unity that appears completely destroyed by this primitive and radical opposition? I admit these two tendencies are contradictory, but it should be noticed that they are not so in the _same objects_. But things that do not meet cannot come into collision. No doubt the sensuous impulsion desires change; but it does not wish that it should extend to personality and its field, nor that there should be a change of principles. The formal impulsion seeks unity and permanence, but it does not wish the condition to remain fixed with the person, that there should be identity of feeling. Therefore these two impulsions are not divided by nature, and if, nevertheless, they appear so, it is because they have become divided by transgressing nature freely, by ignoring themselves, and by confounding their spheres. The office of culture is to watch over them and to secure to each one its proper _limits_; therefore culture has to give equal justice to both, and to defend not only the rational impulsion against the sensuous, but also the latter against the former. Hence she has to act a twofold part: first, to protect sense against the attacks of freedom; secondly, to secure personality against the power of sensations. One of these ends is attained by the cultivation of the sensuous, the other by that of reason.