AGRIPPA, a sceptical philosopher, whose date cannot be accurately determined. He must have lived later than Aenesi demus. To him are ascribed the five tropes (rivr€ rpOroc) which, according to Sextus Empiricus, summarize the attitude of the later ancient sceptics. ( ) Since some thinkers hold that nothing is known but the sensible; others that nothing is known but the in telligible, it f ollows that the only wise course is neither to affirm nor to deny. (2) The proof of one so-called fact depends on an other fact which itself needs demonstration, and so on ad infinitum. (3) The data of sense are relative to the sentient being, those of reason to the intelligent mind; that in different conditions things themselves are seen or thought to be different. Where, then, is the absolute criterion? (4) All knowledge depends on certain hypoth eses, or facts taken f or granted. Such knowledge is hypothetical. (5) The fif th trope points out the impossibility of proving the sen sible by the intelligible inasmuch as it remains to establish the intelligible in its turn by the sensible. Such a process is a vicious circle and has no logical validity. A comparison of these tropes with the ten tropes enumerated in the article AENESIDEMUS shows that scepticism has made an advance into the more abstruse ques tions of metaphysics. The first and the third include all the ideas expressed in the ten tropes, and the other three systematize the more profound difficulties which new thinkers had developed.
See Diogenes Laertius x. 88, and Zeller's Greek Philosophy. Also the articles SCEPTICISM ; AENESIDEMUS.