Our intelligence is imperfect, surely, and newly arisen; the ease with which it can be sweet-talked, overwhelmed, or subverted by other hardwired propensities - sometimes themselves disguised as the cool light of reason - is worrisome.
So with truth - there is a certain moment when one can say, this is the truth and here I put a dot, a stop, and I go to another thing. A judge has to put an end to a deliberation. But for a historian, theres never an end to the past. It can go on and on and on.
. . . the mind is desperate to fix the river {of events} in place: Possessed by ideas of the past, preoccupied with images of the future, it overlooks the plain truth of the moment.