Lives and Opinions of Eminent Philosophers

​The ninth mode is that based on continuity, strangeness, or rarity. Earthquakes, for instance, are not marveled at by those among whom they constantly occur, nor is the sun, because it is seen every day. Favorinus calls the ninth mode the eighth, while Sextus and Aenesidemus call it the tenth; on the other hand, Sextus says the tenth mode is the eighth, and Favorinus says it is the ninth. The tenth mode is that based on comparison with other things, such as the light in relation to the heavy, the strong in relation to the weak, the greater in relation to the less, and the above in relation to the below. The right side, for instance, is not by nature right, but is conceived according to its relation toward the other; when that other has changed its position, it is no longer right.

​Similarly, father and brother are also relative to something, day is relative to the sun, and all things are relative to thought. Things that are relative, therefore, are unknown in themselves. And these are the ten modes. But Agrippa and his followers introduce five others in addition to these: that from disagreement, that which leads into infinite regress, that from relativity, that from hypothesis, and that from reciprocal circularity. The mode from disagreement shows that whatever inquiry is proposed, whether among philosophers or in common usage, is full of the greatest conflict and confusion; that which leads into infinite regress does not allow the matter under inquiry to be confirmed, because one thing receives credibility from another, and so on ad infinitum.

​The mode from relativity asserts that nothing is apprehended by itself, but in connection with something else; whence things are unknown. The mode from hypothesis arises when some think that the first principles of things must be accepted directly as credible and not called in question; which is futile, for someone will hypothesize the opposite. The mode from reciprocal circularity arises whenever that which ought to confirm the matter under inquiry requires credibility from the very matter under inquiry, as if someone confirming that pores exist because effluences occur should take this very existence of pores for the confirmation that effluences occur.

​They also used to abolish all demonstration, criterion, sign, cause, motion, learning, generation, and that anything is by nature good or bad. For every demonstration, they say, consists either of demonstrated premises or of undemonstrated ones. If, then, it consists of demonstrated premises, those too will require some demonstration, and thence to infinity; but if of undemonstrated ones, whether all or some or even a single one is doubted, the whole is also undemonstrated. And if, they say, some things seem to exist that require no demonstration, they are admirable in their judgment if they do not understand that demonstration is needed first of all for this very point, namely that they have credibility from themselves.

​For that the elements are four is not to be confirmed from the fact that the elements are four. In addition to this, when particular demonstrations are distrusted, general demonstration is also distrusted. And in order that we may know that demonstration exists, a criterion is needed; and that a criterion exists, demonstration is needed; whence both, being referred to each other, are incomprehensible. How then could non-evident things be comprehended, when demonstration is unknown? The inquiry is not whether they appear such, but whether they are so in actual reality. They also showed the dogmatists to be simple-minded; for what is concluded from a hypothesis has the character not of an investigation but of an arbitrary postulate. And by such reasoning one can argue even for impossible things.