"The more the ordinary mind takes the opposition between true and false to be fixed, the more is it accustomed to expect either agreement or contradiction with a given philosophical system, and only to see reason for the one or the other in any explanatory statement concerning such a system. It does not conceive the diversity of philosophical systems as the progressive evolution of truth; rather, it sees only contradiction in that variety. The bud disappears when the blossom breaks through, and we might say that the former is refuted by the latter; in the same way when the fruit comes, the blossom may be explained to be a false form of the plant's existence, for the fruit appears as its true nature in place of the blossom. These stages are not merely differentiated; they supplant one another as being incompatible with one another. But the ceaseless activity of their own inherent nature makes them at the same time moments of an organic unity, where they not merely do not contradict one another, but where one is as necessary as the other; and this equal necessity of all moments constitutes alone and thereby the life of the whole. But contradiction as between philosophical systems is not wont to be conceived in this way; on the other hand, the mind perceiving the contradiction does not commonly know how to relieve it or keep it free from its onesidedness, and to recognize inwhat seems conflicting and inherently antagonistic the presence of mutually necessary moments" (Preface to The Phenomenology of Spirit).

Hegel on the web

13.  The nature of philosophical truth and its method

"Philosophy, on the contrary, does not deal with a determination that is non-essential, but with a determination so far as it is an essential factor. The abstract or unreal is not its element and content, but the real, what is self-establishing, has life within itself, existence in its very notion. It is the process that creates its own moments in its course, and goes through them all; and the whole of this movement constitutes its positive content and its truth. This movement includes, therefore, within it the negative factor as well, the element which would be named falsity if it could be considered one from which we had to abstract. The element that disappears has rather to be looked at as itself essential, not in the sense of being something fixed, that has to be cut off from truth and allowed to lie outside it, heaven knows where; just as similarly the truth is not to be held to stand on the other side as an immovable lifeless positive element. Appearance is the process of arising into being and passing away again, a process that itself does not arise and does not pass away, but is per se, and constitutes reality and the life-movement of truth. The truth is thus the bacchanalian revel, where not a member is sober; and because every member no sooner becomes detached than it eo ipso collapses straightway, the revel is just as much a state of transparent unbroken calm. Judged by that movement, the particular shapes which mind assumes do not indeed subsist any more than do determinate thoughts or ideas; but they are, all the same, as much positive and necessary moments, as negative and transitory. In the entirety of the movement, taken as an unbroken quiescent whole, that which obtains distinctness in the course of its process and secures specific [106] existence, is preserved in the form of a self -recollection, in which existence is self-knowledge, and self-knowledge, again, is immediate existence" (Preface to The Phenomenology of Spirit).