, however, to present proofs _in infinitum_, so 123
that one will not be able to prove that one idea is to be
preferred to another. Since then one cannot either without proof
or with proof judge the ideas in question, the suspension of
judgment results, and how each thing appears according to this
or that position, or this or that distance, or this or that
place, we perhaps are able to say, but what it really is it is
impossible to declare, for the reasons which we have mentioned.

THE SIXTH TROPE.

The sixth Trope is the one based upon mixtures, according to 124
which we conclude that since no object presents itself alone,
but always together with something else, it is perhaps possible
to say of what nature the mixture is, of the thing itself, and
of that with which it is seen, but of what sort the external
object really is we shall not be able to say. Now it is evident,
I think, that nothing from without is known to us by itself, but
always with something else, and that because of this fact it
appears different. The color of our skin, for example, is 125
different seen in warm air from what it is in cold, and we
could not say what our color really is, only what it is when
viewed under each of these conditions. The same sound appears
different in rare air from what it is in dense, and aromas are
more overpowering in the warm bath and in the sun than they are
in the cold air, and a body surrounded by water is light, but by
air heavy. Leaving aside, however, outer mixtures, our eyes 126
have inside of them coatings and humors. Since then visible
things are not seen without these, they will not be accurately
comprehended, for it is the mixture that we perceive, and for
this reason those who have the jaundice see everything yellow,
and those with bloodshot eyes bloody. Since the same sound
appears different in broad open places from what it does in
narrow and winding ones, and different in pure air and in
impure, it is probable that we do not perceive the tones
unmixed; for the ears have narrow winding passages filled with
vaporous secretions, which it is said gather from places around
the head. Since also there are substances present in the 127
nostrils and in the seat of the sense of taste, we perceive the
things smelled and the things tasted in connection with them,
and not unmixed. So that because of mixture the senses do not
perceive accurately what the external objects a