If there is "only one form of Being, the ego," and all other forms of Being are made in its own image,--if, in short, the belief in the "ego," together with the belief in logic, stands and falls with the metaphysical truth of the categories of reason: if, in addition, the "ego" is shown to be something that is _evolving: then----_ 520. The continual transitions that occur, forbid our speaking of the "individual," etc.; the "number" of beings itself fluctuates. We should know nothing of time or of movement, if, in a rough way, we did not believe we saw things "standing still" behind or in front of things moving. We should also know just as little about cause and effect, and without the erroneous idea of "empty space" we should never have arrived at the concept of space at all. The principle of identity is based on the "fact of appearance" that there are some things alike. Strictly speaking, it would not be possible to "understand" and "know" an evolving world; something which is called "knowledge" exists only in so far as the "understanding" and "knowing" intellect already finds an adjusted and rough world to hand, fashioned out of a host of mere appearances, but become fixed _to_ the extent in which this kind of appearance has helped to preserve life; only to this extent is "knowledge" possible--that is to say, as a measuring of earlier and more recent errors by one another. 521. _Concerning logical appearance._--The concept "individual" and the concept "species" are equally false and only apparent. "_Species_" only expresses the fact that an abundance of similar creatures come forth at the same time, and that the speed of their further growth and of their further transformation has been made almost imperceptible for a long time: so that the actual and trivial changes and increase of growth are of no account at all (--a stage of evolution in which the process of evolving is not visible, so that, not only does a state of equilibrium _seem_ to have been reached, but the road is also made clear for the error of supposing _that an actual goal has been reached_--and that evolution had a goal...). The form seems to be something enduring, and therefore valuable; but the form was invented merely by ourselves; and however often "the same form is attained," it does not signify that it _is the same form,--because something new always appears_; and we alone, who compare, reckon the new with the old, in so far as it resembles the latter, and embody the two in the unity of "form." As if a _type_ had to be reached and were actually intended by the formative processes.