Tertullian

“ Whence is it to know what is necessary for itself under given circumstances, from the very necessity of natural causes, if it knows not its own property, and what is necessary for it? To recognise this indeed is within the competence of every soul; it has, I mean, a practical knowledge of itself, without which knowledge of itself no soul could possibly have exercised its own functions. ”

“ Well, now, let it be granted that the soul is made apparent by the flesh, [1] on the assumption that it was evidently necessary [2] that it should be made apparent in some way or other, that is, as being incognizable to itself and to us: there is still an absurd distinction in this hypothesis, which implies that we are ourselves separate from our soul, when all that we are is soul. Indeed, [3] without the soul we are nothing; there is not even the name of a human being, only that of a carcase. If, then, we are ignorant of the soul, it is in fact the soul that is ignorant of itself. ”

“ I suppose, too, that it is especially suitable that man, the only rational animal, should have been furnished with such a soul as would make him the rational animal, itself being pre-eminently rational. Now, how can that soul which makes man a rational animal be itself rational if it be itself ignorant of its rationality, being ignorant of its own very self? ”