Psycho-analysis regarded everything mental as being in the first place unconscious; the further quality of “ consciousness” might also be present, or again it might be absent. This of course provoked a denial from the philosophers, for whom “consciousness” and “mental” were identical, and who protested that they could not conceive of such an absurdity as the “unconscious mental.” There was no help for it, however, and this idiosyncrasy of the philosophers could only be disregarded with a shrug. Experience (gained from pathological material, of which the philosophers were ignorant) of the frequency and power of impulses of which one knew nothing directly, and whose existence had to be inferred like some fact in the external world, left no alternative open. It could be pointed out, incidentally, that this was only treating one's own mental life as one had always treated other people's. One did not hesitate to ascribe mental processes to other people, although one had no immediate consciousness of them and could only infer them from their words and actions. But what held good for other people must be applicable to oneself. Anyone who tried to push the argument further and to conclude from it that one's own hidden processes belonged actually to a second consciousness would be faced with the concept of a consciousness of a thing of which one knew nothing, of an “unconscious consciousness” - and this would scarcely be preferable to the assumption of an “unconscious mental.” . . . The further question as to the ultimate nature of this unconscious is no more sensible or profitable than the older one as to the nature of the conscious.