III.
The proper and useful habit of designating that which is permanent by a single name, and of comprehending the same in a single thought, without analysing at each operation its constituent parts, is liable to come into singular conflict with the tendency to separate these constituent parts. The obscure image formed of the permanent, which does not perceptibly change when one or another constituent part is taken away, appears to be something existent by itself. Inasmuch as it is possible to take away singly every constituent part without effecting the capacity of the image formed to represent the totality involved, or effecting its subsequent recognition, it is imagined that it is possible to take away all these parts and yet have something remaining. Thus arises the monstrous idea of a thing of itself, different from, and incognisable with relation to, its "phenomenal" existence.
Thing, body, matter, are nothing apart from this complex of colors, sounds, and so forth—apart from their so-called marks, or characteristics. That Protean, illusory philosophical problem of a single independent thing with many properties, arises from the misunderstanding of the fact, that extensive comprehension and accurate separation, although both are temporarily justifiable and profitable for a number of purposes, can not and must not be employed simultaneously. A body is single and unchangeable so long as it is not required to take details into consideration. Thus both the earth and a billiard ball are spheres so long as we disregard all minor deviations from the spherical form, and greater exactitude is not necessary. But if we are compelled to carry on investigations in orography or microscopy both bodies cease to be spheres.