But definition is the first, still undeveloped concept, and in that it has to apprehend the simple determinateness of the subject matter, and this apprehension is to be something simple, it can employ for the purpose only one of the subject's immediate so called properties, a determination of sensuous existence or of representation; the singling out, then, of this property through abstraction is what constitutes the simplicity, and for universality and essentiality the concept must resort to empirical universality, to persistence under altered circumstances and to the reflection