At this point I must ask the reader carefully to fasten in his mind these various distinctions. Nor will it be difficult to do so after a small amount of attention. It will be remembered that in Chapter IV. I instituted a distinction between concepts as higher and lower, which was methodically similar to that which I have now to institute between recepts. A “lower concept” was defined to be nothing more than a “named recept,”[106] while a “higher concept” was understood to be one that is “compounded of other concepts”—_i.e._ the named result of a grouping of concepts, as when we speak of the “mechanical equivalent of heat.” So that altogether we have four stages of ideation to recognize, each of which occupies an immensely large territory of mind. These four stages I will present in serial order. (1) _Lower Recepts_, comprising the mental life of all the lower animals, and so including such powers of receptual connotation as a child when first emerging from infancy shares with a parrot. (2) _Higher Recepts_, comprising all the extensive tract of ideation that belongs to a child between the time when its powers of receptual connotation first surpass those of a parrot, up to the age at which connotation as merely denotative begins to become also denominative. (3) _Lower Concepts_, comprising the province of conceptual ideation where this first emerges from the higher receptual, up to the point where denominative connotation has to do, not merely with the naming of recepts, but also with that of associated concepts. (4) _Higher Concepts_, comprising all the further excellencies of human thought.