All thought, judgment, perception, regarded as an act of _comparing_[2] has as a first condition the act of _equalising,_ and earlier still the act of _"making equal."_ The process of making equal is the same as the assimilation by the amœba of the nutritive matter it appropriates. "Memory" late, in so far as the equalising instinct appears to have been _subdued_: the difference is preserved. Memory--a process of classification and collocation; active--who? [Footnote 2: The German word _vergleichen,_ meaning "to compare," contains the root "equal" _(gleich)_ which cannot be rendered in English. TR.] 502. In regard to the _memory,_ we must unlearn a great deal: here we meet with the greatest temptation to assume the existence of a "soul," which, irrespective of time, reproduces and recognises again and again, etc. What I have experienced, however, continues to live "in the memory"; I have nothing to do with it when memory "comes," my will is inactive in regard to it, as in the case of the coming and going of a thought. Something happens, of which I become conscious: now something similar comes--who has called it forth? Who has awakened it? 503. The whole apparatus of knowledge is an abstracting and simplifying apparatus--not directed at knowledge, but at the _appropriation_ of things: "end" and "means" are as remote from the essence of this apparatus as "concepts" are. By the "end" and the "means" a process is appropriated (--a process is _invented_ which may be grasped), but by "_concepts_" one appropriates the "things" which constitute the process. 504. _Consciousness_ begins outwardly as co-ordination and knowledge of impressions,--at first it is at the point which is remotest from the biological centre of the individual; but it is a process which deepens and which tends to become more and more an inner function, continually approaching nearer to the centre. 505. Our perceptions, as we understand them--that is to say, the sum of all those perceptions the consciousness whereof was useful and essential to us and to the whole organic processes which preceded us: therefore they do not include all perceptions (for instance, not the electrical ones);--that is to say, we have _senses_ only for a definite selection of perceptions--such perceptions as concern us with a view to our self-preservation. _Consciousness extends so far only as it is useful._ There can be no doubt that all our sense-perceptions are entirely permeated by valuations (useful or harmful--consequently, pleasant or painful). Every particular colour; besides being a colour, expresses a value to us (although we seldom admit it, or do so only after it has affected us exclusively for a long time, as in the case of convicts in gaol or lunatics). Insects likewise react in different ways to different colours: some like this shade, the others that. Ants are a case in point. 506.