II . By the word “idea” I understand that form of any thought, by the immediate perception of which I am conscious of that same thought; so that I can express nothing in words, when I understand what I say, without making it certain, by this alone, that I possess the idea of the thing that is signified by these words. And thus I give the appellation idea not to the images alone that are depicted in the fantasy; on the contrary, I do not here apply this name to them, in so far as they are in the corporeal fantasy, that is to say, in so far as they are depicted in certain parts of the brain, but only in so far as they inform the mind itself, when turned towards that part of the brain.