Every argument, whatever be the matter of it, consists in bringing
a _Case_ under a _Precedent_, and applying to the case ideally the
better knowledge possessed of the precedent. The _Conclusion_ (also
called Inference or Deduction) is the result of this application, and
is always an addition to our stock of ideas.
A conclusion has never the same reality as actual experience. It is
not 'true' in that sense, though it may be 'morally' true, that is,
we are ready to act upon it without hesitation--to stake our life or
fortune on it. As regards actual or experienced fact there can be no
argument, since it is useless to 'predict' what we already know.
Academical logicians have a doctrine the reverse of this. They assert
that their syllogisms yield conclusions that are always as certain as
the premises. Grant their premises and you are obliged to accept their
conclusions. This is so, because a regular syllogistic conclusion is
simply a restating in other words of the information, or part of the
information, already contained in the premises. If the syllogism has
any use at all, it is merely as an aid to recollection; no new idea
is generated by it. It is needless to insist on a fact so notorious as
that ordinary rational conclusions--those that form the staple of our
daily thought--are not by any means so certain as the data from which
they are drawn. For example, the sky is red and lowering this evening,
and we conclude therefrom that the weather will be bad to-morrow.
There is no doubt about the present aspect of the sky, but much doubt
about the inference.
The form of an act of reasoning or argumentation may be rendered
plainer by a diagram.
S A
--- ---
C _I_
--- ---
S A represents the precedent. S is the Subject or body of the
precedent; A (the _Applicate_) is one property, or a part, or a
relation of S abstracted from the rest to illustrate a case. C is the
case; _I_ is the conclusion (or inference). _I_ results from imagining
C to be associated with a property or relation similar to A. The sum
of our _I_'s constitutes what we know of the world and man before
we were born, of what is taking place in other parts of the world or
universe, of what may take place in the future, and of the concealed
and inaccessible parts of present objects. This is true not only
of the results of our own reasoning but of what we have learned as
verified knowledge from others, for the interpretation of language is,
in the last analysis, a rational conclusion.
All the parts of an argument exist in the mind, but they are not
always expressed in language. When treated dialectically the implicit
members are expressed, and the terms arranged so as to show as clearly
as possible the nature of the argument. The following are the
points most necessary to be observed in constructing or analysing an
argument.
(1) C must resemble S, for that is the basis of the argument. If C
is not felt to be like S, or (as sometimes happens) is explicitly
declared to be unlike S, there can be no conclusion. The precedent is
not applicable to the case. A may, or may not, be associated with S;
that is to say, a verbal negation may appear in the statement of the
relation of S to A, but there must be no negation with respect to the
relation of C to S.
The resemblance of C to S may, however, vary in degree from the
faintest analogy to community of species. The difference between them
may far outweigh their resemblance. There may even be no material
likeness, but only a similarity of function, or position, or of any
the most trivial attribute. Only it is to be observed that the kind
and degree of resemblance between S and C determine the kind
and degree of resemblance between A and _I_. We must not infer
specifically unless the case is specifically like the precedent.
In all other instances we can only infer proportionally or by
transfusion.
(2) None of the antecedents must be a verbal or identical proposition,
that is, a proposition which merely substitutes one name or nominal
phrase for another; nor must the case be merely the precedent
expressed in other words, or the precedent a paraphrase of the case.
In any of these circumstances one of the elements of the argument is
wanting; we have two names for one thing or two propositions giving
the same information.
(3) The precedent may (as has been already remarked) be a general
idea, or may be an individual idea or object. If S A has occurred
frequently it is certain to be generalised, and so may form a maxim,
a law, a rule, an induction, &c. But one well-observed precedent is
enough to suggest a conclusion, if there has been no experience to the
contrary. There is therefore no dialectical difference between arguing
from a general idea (class notion) to an individual or subordinate
idea, and arguing from one individual to another. Comparison and
inference occur in both.
(4) After separating A from S care should be taken that it is A and
not S that is used to generate _I_. Examples are plentiful of theorems
in which S and A change parts, which invalidates the conclusion. Other
errors in stating theorems intended to be arguments will be noticed
under the head of 'Fallacies.'
The following is an argument conformable to the above rules.
Tyrants | deserve death
--------------------+-----------------------------
Caesar was a tyrant | _no doubt he deserved death_
This square mode of stating the argument is adapted from the general
type, and brings out the mutual relations of the compared parts better
than the three-lined arrangement. The word 'therefore,' which usually
introduces a logical conclusion, is ambiguous. It may mean that the
antecedents are the causes of the fact mentioned in the conclusion,
or merely that the antecedents are the reasons why we believe the
conclusion. The former is the scientific 'therefore,' the latter is
the purely dialectical. I shall generally omit the illative word, and
print conclusions in italics, besides entering them invariably in the
fourth compartment of the parallel when this arrangement is adopted.
An idea once generated in the intellect is not to be erased at
pleasure. It can be obliterated only by the process of forgetting. If
after we have formed a dialectical conclusion we meet with evidence
that contradicts it, the only result of that evidence is to affix
a mark of falsity to the conclusion, so that as often as it is
recollected the stigma is recollected too, and neutralises the effect
of the idea. A negative or destructive argument is thus, plasmically
speaking, a positive addition to the idea it seeks to efface. For the
time being it renders the idea more conspicuous, as the word CANCELLED
stamped in large letters across a document makes it more evident than
it was before; but no doubt the stigmatising of an idea hastens the
process of oblivion, for we thenceforth bestow less attention upon it.
Stigmatic arguments are not another species, but merely the ordinary
constructive arguments used for a particular purpose.
Suppose we have inferred from the general resemblance of the earth to
the moon that the latter is inhabited, we stigmatise this belief by
such an argument as--
Without air | animals cannot live
----------------------------+-----------------------------------
There is no air in the moon | _there can be no life in the moon_
There is an exception to the rule that argument is superfluous when
the speaker has already verified the conclusion. It is when he is
addressing a person who has not had the same experience as himself and
who doubts his word. The speaker may then resort to arguments drawn
from antecedents recognised by the hearer, if any such are applicable
to the subject. But a fact may be truly reported though neither the
witness nor a sceptical hearer can find dialectical antecedents to
prove it, for there may be no relation between the fact in question
and any prior knowledge they possess, or they may not be able to find
the relation.
This brings us again to that view of the intellect which represents
it as artificial and limited by experience. Man is rational only
on matters familiar to him; in utterly novel circumstances he is
irrational, and must fall back for guidance on his general mental
sentiment, or the advice of persons more experienced than himself.