But, secondly, contradiction, at least as here understood, is an expression, or in experience a means to the expression, as well as to the maintenance, of real unity. In general this is because real unity cannot take sides, and so can never reside in anything that is, but must rather be served by the co-operation of all things and in particular by their mutually corrective or balancing differences. This no doubt will appear to some readers as just one more example of a philosopher's impossible subtleties, as a mountain with its top in so rare an atmosphere that the common man would not dare to climb it if he could. Yet, suppose together we rise to the heights of this seeming impossibility by a little unprejudiced study of the conditions, remembering that the summits of very wonderful mountains, plainly impossible of ascent, have often been reached [p.138] from the other side, and that difficulties of breathing are often due to a needless exhaustion. To take a first step, then, contradiction is only difference, or contrast, at its limit. Naturally there is some opposition, some mutual resistance, in all difference, in that, for example, between one man and another, or one thing and another, between religion and art, red and green, or warm and hot, and often the difference or the opposition seems very slight; but contradiction, so called, is only this difference abstracted and unrestrained--it is difference at its worst or best, difference as only opposition, or, once more, difference where any possible unity of the things opposed has lost all material ground or all chance of actual, visible form, and has become, accordingly, at most merely an empty, abstract principle. Contradiction, then, is difference so wide that unity seems wholly betrayed rather than served or maintained. A real unity, however, requires for its realization just the freedom from material form or ground which such extreme difference would force upon it. It therefore gains instead of losing reality by passing into the world of the materially and visibly empty and abstract, or, say, by leaving behind any hope of a finite residence and entering the sphere of the infinite, to which difference, or at least contradiction, so cordially invites--or expels--it. And, this being true, we can see how unity is served or maintained, as was said, by the contradictions of experience.