De Agricultura

And those who do not arrive at this point are by philosophers indeed called wise men, but it is without their own knowledge: for they say that it is impossible for them who have advanced as far as the perfection of wisdom, and who have now for the first time reached its summit to be aware of their own perfection; for they affirm that it is impossible for both these things to happen at the same time, namely the arrival at the desired goal, and the apprehension that one has arrived there; but they affirm that on the border between the two, there is ignorance, of such a sort, that it is not far removed from knowledge, but that it is very near to it, and close to its doors.