The seventh mode has reference to distances, and position, and space, and to the objects which are in space. In this mode one establishes the fact that objects which we believe to be large, sometimes appear small; that those which we believe to be square, sometimes appear round; that those which we fancy even, appear full of projections; those which we think straight, seem bent; and those which we believe to be colourless, appear of quite a different complexion. Accordingly, the sun, on account of its distance from us, appears small. The mountains too, at a distance,[135] appear airy masses and smooth, but when beheld close, they are rough. Again, the sun has one appearance at his rise, and quite a different one at midday. And the same body looks very different in a wood from what it does on plain ground. So too, the appearance of an object changes according to its position as regards us; for instance, the neck of a dove varies as it turns. Since then, it is impossible to view these things irrespectively of place and position, it is clear that their real nature is not known.
The eighth mode has respect to the magnitudes or quantities of things; or to the heat or coldness, or to the speed or slowness, or to the paleness or variety of colour of the subject. For instance, a moderate quantity of wine when taken invigorates, but an excessive quantity weakens. And the same is the case with food, and other similar things.
The ninth depends upon the frequency, or rarity, or strangeness of the thing under consideration. For instance, earthquakes excite no wonder among those nations with whom they are of frequent occurrence; nor does the sun, because he is seen every day.
The ninth mode is called by Phavorinus, the eighth, and by Sextus and Ænesidemus, the tenth; and Sextus calls the tenth the eighth, which Phavorinus reckons the tenth as the ninth in order.
The tenth mode refers to the comparison between one thing and another; as, for instance, between what is light and what is heavy; between what is strong and what is weak; between what is greater and what is less; what is above and what is below. For instance, that which is on the right, is not on the right intrinsically and by nature, but it is looked upon as such in consequence of its relation to something else; and if that other thing be transposed, then it will no longer be on the right. In the same way, a man is spoken of as a father, or brother, or relation to some one else; and day is called so in relation to the sun: and everything has its distinctive name in relation to human thought: therefore, those things which are known in relation to others, are unknown of themselves.
And these are the ten modes.
X. But Agrippa adds five other modes to them. One derived from the disagreement of opinions; another from the necessity of proceeding ad infinitum from one reasoning to another; a third from relation; a fourth from hypothesis; and the last from the reciprocal nature of proofs.
That which refers to the disagreement of opinions, shows that all the questions which philosophers propose to themselves, or which people in general discuss, are full of uncertainty and contradiction.
That which is derived from the necessity of proceeding incessantly from one reasoning to another, demonstrates that it is impossible for a man ever, in his researches, to arrive at undeniable truth; since one truth is only to be established by another truth; and so on, ad infinitum.