292 l//-22
based on relativity, one based on hypothesis and one based on circular rea-
soning.
[1] The one based on disagreement demonstrates that whatever ques-
tion is advanced by philosophers or by everyday life is a matter of the
greatest contention and full of confusion.
[2] The one based on infinite regress forbids that that which has been
sought has been firmly established because confidence in it is based on
establishing something else which is in turn based on establishing some-
thing else, and so on to infinity.
[3] 89. The one based on relativity says that nothing is understood
just by itself, but always with something else; for which reason, things
are unknowable.
[4] The mode constructed on hypothesis is used when people think
that the principles of things should be assumed as immediately plausible
and not questioned. But this is in vain, for someone will hypothesize
the opposite.
[5] The mode based on circularity occurs whenever that which ought
to provide support for some claim needs to have its own establishment
based on the plausibility of the claim, as, for example, if someone based
the existence of pores on the occurrence of emanations and took the
existence of pores as establishing the occurrence of emanations.
- They also used to abolish all demonstration, criterion, sign, cause,
motion, learning, generation and something being good or bad by nature.
For every demonstration, they say, is constructed out of things [claimed
to be] previously demonstrated or things not demonstrated. If the former,
then they will need to produce the demonstration [for the things used
as support], and this will go on indefinitely. If the latter, then if either
all [of the undemonstrated supports], or some, or even a single one, is
in doubt, then the whole argument is undemonstrated. If it is held that
they say there are things in need of no demonstration, then those who
hold this are mental marvels if they don't grasp that there must be a
demonstration of the fact that these things are self-confirming. - Nor should the fact that there are four elements be established
on the grounds that there are four elements. In addition, if particular
demonstrations are untrustworthy, so is demonstration in general. And
in order that we might know that there is [such a thing as] demonstration,
a criterion is needed; and in order that we might know that there is a
criterion, a demonstration is needed. So, the demonstration and the
criterion, each dependent on the other, are ungraspable. How then could
someone grasp non-evident things, being ignorant of the demonstration?
For one seeks not to discover if things appear thus and so, but whether
they are really so.