I have discovered that the human mind in all its operations manifests, although simple, a three fold character in that simplicity. And the study of this triple nature of all mental actions is useful because it gives us, among other things, a critical idea of the nature of reasoning and of the kind of reasoning which is of value, of the kind which is not.

I was first led to these observations by the consideration of perception. Let us consider this mental action in relation, say, to a piano.

Take firstly the case of a civilized man, who knows of course what a piano is. In childhood the idea of piano has been acquired, it is now, practically, a primary idea, in his mind, a kind of Category already. Now when this man sees a piano, the operation which takes place is this: the idea of piano passes out of him so to speak into the piano itself and returns to him individualized — as the notion of a particular piano, which is of a certain size, of certain colour, of a certain make. The general passes into the particular and returns to itself particularized.

Let us now consider the same case in a negro, in a savage who has never seen a piano, nor ever heard of it. In his case the primary idea is not the idea of piano, it is the idea of colour, of form, of size and others of the same kind.