ALL instruction given or received by way of argument proceeds
from pre-existent knowledge. This becomes evident upon a survey of all
the species of such instruction. The mathematical sciences and all other
speculative disciplines are acquired in this way, and so are the two forms
of dialectical reasoning, syllogistic and inductive; for each of these
latter make use of old knowledge to impart new, the syllogism assuming
an audience that accepts its premisses, induction exhibiting the universal
as implicit in the clearly known particular. Again, the persuasion exerted
by rhetorical arguments is in principle the same, since they use either
example, a kind of induction, or enthymeme, a form of syllogism.
The pre-existent knowledge required is of two kinds.
In some cases admission of the fact must be assumed, in others comprehension
of the meaning of the term used, and sometimes both assumptions are
essential. Thus, we assume that every predicate can be either truly affirmed
or truly denied of any subject, and that 'triangle' means so and so;
as regards 'unit' we have to make the double assumption of the meaning
of the word and the existence of the thing. The reason is that these several
objects are not equally obvious to us. Recognition of a truth may in
some cases contain as factors both previous knowledge and also knowledge
acquired simultaneously with that recognition-knowledge, this latter, of
the particulars actually falling under the universal and therein already
virtually known. For example, the student knew beforehand that the angles
of every triangle are equal to two right angles; but it was only at the
actual moment at which he was being led on to recognize this as true in
the instance before him that he came to know 'this figure inscribed in the
semicircle' to be a triangle. For some things (viz. the singulars finally
reached which are not predicable of anything else as subject) are only
learnt in this way, i.e. there is here no recognition through a middle of
a minor term as subject to a major. Before he was led on to recognition
or before he actually drew a conclusion, we should perhaps say that in a
manner he knew, in a manner not.
If he did not in an unqualified sense of the term
know the existence of this triangle, how could he know without qualification
that its angles were equal to two right angles? No: clearly he knows
not without qualification but only in the sense that he knows universally.
If this distinction is not drawn, we are faced with the dilemma in the
Meno: either a man will learn nothing or what he already knows; for we cannot
accept the solution which some people offer. A man is asked, 'Do you,
or do you not, know that every pair is even?' He says he does know it.
The questioner then produces a particular pair, of the existence, and so
a fortiori of the evenness, of which he was unaware. The solution which
some people offer is to assert that they do not know that every pair is even,
but only that everything which they know to be a pair is even: yet what
they know to be even is that of which they have demonstrated evenness,
i.e. what they made the subject of their premiss, viz. not merely every
triangle or number which they know to be such, but any and every number
or triangle without reservation. For no premiss is ever couched in the form
'every number which you know to be such', or 'every rectilinear figure
which you know to be such': the predicate is always construed as applicable
to any and every instance of the thing. On the other hand, I imagine
there is nothing to prevent a man in one sense knowing what he is learning,
in another not knowing it. The strange thing would be, not if in some
sense he knew what he was learning, but if he were to know it in that precise
sense and manner in which he was learning it.
World-Wide Web presentation copyright (C) 1994-96 by Daniel C. Stevenson.