On [Greek: epistaemae], from
I. Post. Analyt. chap. i. and ii.
(Such parts only are translated as
throw light on the Ethics.)
All teaching, and all intellectual
learning, proceeds on the basis of previous knowledge,
as will appear on an examination of all. The
Mathematical Sciences, and every other system, draw
their conclusions in this method. So too of reasonings,
whether by syllogism, or induction: for both
teach through what is previously known, the former
assuming the premisses as from wise men, the latter
proving universals from the evidentness of the particulars.
In like manner too rhetoricians persuade, either through
examples (which amounts to induction), or through
enthymemes (which amounts to syllogism).
Well, we suppose that we know
things (in the strict and proper sense of the word)
when we suppose ourselves to know the cause by reason
of which the thing is to be the cause of it; and that
this cannot be otherwise. It is plain that the
idea intended to be conveyed by the term knowing
is something of this kind; because they who do not
really know suppose themselves thus related to the
matter in hand and they who do know really are so
that of whatsoever there is properly speaking Knowledge
this cannot be otherwise than it is Whether or no there
is another way of knowing we will say afterwards,
but we do say that we know through demonstration,
by which I mean a syllogism apt to produce Knowledge,
i.e. in right of which through having it, we know.
If Knowledge then is such as we have
described it, the Knowledge produced by demonstrative
reasoning must be drawn from premisses true
and first, and incapable of syllogistic proof,
and better known, and prior in order of
time, and causes of the conclusion, for
so the principles will be akin to the conclusion demonstrated.
(Syllogism, of course there may be
without such premisses, but it will not be demonstration
because it will not produce knowledge).
True, they must be, because
it is impossible to know that which is not.
First, that is indemonstrable,
because, if demonstrable, he cannot be said to know
them who has no demonstration of them for knowing such
things as are demonstrable is the same as having demonstration
of them.
Causes they must be, and better
known, and prior in time, causes,
because we then know when we are acquainted with the
cause, and prior, if causes, and known beforehand,
not merely comprehended in idea but known to exist
(The terms prior, and better known, bear two senses
for prior by nature and prior relatively
to ourselves are not the same, nor better known
by nature, and better known to us I mean,
by prior and better known relatively to ourselves,
such things as are nearer to sensation, but abstractedly
so such as are further Those are furthest which are
most universal those nearest which are particulars,
and these are mutually opposed) And by first,
I mean principles akin to the conclusion, for
principle means the same as first And the principle
or first step in demonstration is a proposition incapable
of syllogistic proof, i. e. one to which there is none
prior. Now of such syllogistic principles I call
that a [Greek: thxsis] which you cannot demonstrate,
and which is unnecessary with a view to learning something
else. That which is necessary in order to learn
something else is an Axiom.
Further, since one is to believe and
know the thing by having a syllogism of the kind called
demonstration, and what constitutes it to be such
is the nature of the premisses, it is necessary not
merely to know before, but to know better
than the conclusion, either all or at least some
of, the principles, because that which is the cause
of a quality inhering in something else always inheres
itself more as the cause of our loving is itself more
lovable. So, since the principles are the cause
of our knowing and behoving we know and believe them
more, because by reason of them we know also the conclusion
following.
Further: the man who is to have
the Knowledge which comes through demonstration must
not merely know and believe his principles better
than he does his conclusion, but he must believe nothing
more firmly than the contradictories of those principles
out of which the contrary fallacy may be constructed:
since he who knows, is to be simply and absolutely
infallible.