Book 9
11.94
We must not assume that what convinces us is actually true. For the same thing does not convince every one, nor even the same people always. Persuasiveness sometimes depends on external circumstances, on the reputation of the speaker,
11.94
on his ability as a thinker or his artfulness, on the familiarity or the pleasantness of the topic.
11.94
Again, they would destroy the criterion by reasoning of this kind. Even the criterion has either been critically determined or not. If it has not, it is definitely untrustworthy, and in its purpose of distinguishing is no more true than false. If it has, it will belong to the class of particular judgements, so that one and the same thing determines and is determined, and the criterion which has determined will have to be determined by another, that other by another, and so on ad infinitum.
11.95
In addition to this there is disagreement as to the criterion, some holding that man is the criterion, while for some it is the senses, for others reason, for others the apprehensive presentation. Now man disagrees with man and with himself, as is shown by differences of laws and customs. The senses deceive, and reason says different things. Finally, the apprehensive presentation is judged by the mind, and the mind itself changes in various ways. Hence the criterion is unknowable, and consequently truth also.
