Book 9
11.96
They deny, too, that there is such a thing as a sign. If there is, they say, it must either be sensible or intelligible. Now it is not sensible, because what is sensible is a common attribute, whereas a sign is a particular thing. Again, the sensible is one of the things which exist by way of difference, while the sign belongs to the category of relative. Nor is a sign an object of thought, for objects of thought are of four kinds, apparent judgements on things apparent, non-apparent judgements on things nonapparent, non-apparent on apparent, or apparent on non-apparent; and a sign is none of these, so that there is no such thing as a sign. A sign is not apparent on apparent, for what is apparent needs no sign; nor is it non-apparent on non-apparent, for what is revealed by something must needs appear; nor is it non-apparent on apparent, for that which is to afford the means of apprehending something else must itself be apparent;
11.97
nor, lastly, is it apparent on non-apparent, because the sign, being relative, must be apprehended along with that of which it is the sign, which is not here the case. It follows that nothing uncertain can be apprehended; for it is through signs that uncertain things are said to be apprehended.This conclusion would debar us from all extension of knowledge beyond what is apparent here and now; whereas the dogmatists permit us from such facts to advance to what is not immediately evident, the realm of the unknown or as yet unascertained (ἄδηλον)..
11.97
Causes, too, they destroy in this way. A cause is something relative; for it is relative to what can be caused, namely, the effect. But things which are relative are merely objects of thought and have no substantial existence.
