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first on the Premiss, and then on the Conclusion; the word “prove,” on the contrary, leads the mind from the conclusion to the Premiss. Hence, the substantives derived from these words respectively, are often used to express that which, on each occasion, is last in the mind; Inference being often used to signify the Conclusion (i. e. Proposition inferred) and Proof, the Premiss. We say, also, “How do you prove that?” and “What do you infer from that?” which sentences would not be so properly expressed if we were to transpose those verbs.
One might, therefore, define Proving, “the assigning of a reason or argument for the support of a
given proposition ;” and Inferring, “ the de* duction of a Conclusion from given Premises."
In the one case our Conclusion is given, (i. e. set before us) and we have to seek for arguments ; in the other, our Premises are given, and we have to seek for a Conclusion: i.e. to put together our own propositions, and try what will follow from them; or, to speak more Logically, in the one case, we seek to refer the Subject of which we would predicate something, to a class to which that Predicate will (affirmatively or negatively) apply; in the other, we seek to find comprehended, in the Subject of which we have predicated something, some other term to which that
Predicate had not been before applied.* Each of these is a definition of Reasoning.
To infer, then, is the business of the Philo- Investigator sopher; to prove, of the Advocate ; the former, from the great mass of known and admitted truths, wishes to elicit any valuable additional truth whatever, that has been hitherto unperceived; and perhaps, without knowing, with certainty, what will be the terms of his Conclusion. Thus the Mathematician, e.g. seeks to ascertain what is the ratio of circles to each other, or what is the line whose square will be
equal to a given circle; the Advocate, on the y other hand, has a Proposition put before him,
which he is to maintain as well as he can : his business, therefore, is to find middle terms (which is the inventio of Cicero); the Philosopher's, to combine and select known facts, or principles, suitably, for gaining from them Conclusions which, though implied in the Premises, were before unperceived: in other words, for making “ Logical Discoveries."
To put the same thing in another point of view, we may consider all questions as falling
“Proving" may be compared to the act of putting away any article into the proper receptacle of goods of that description; "inferring," to that of bringing out the article when needed.
under two classes ; viz. “ What shall be predicated of a certain Subject;" and which Copula, affirmative or negative, shall connect a certain Subject and Predicate : we inquire, in short, either, 1st, " What is A ?” or, 2d, “ Is A, B, or is it not?” The former class of questions belongs to the Philosopher; the (latter to the Advocate.*-(See Rhet. Appendix G. p. 387.)
* The distinction between these two classes of questions is perhaps best illustrated by reference to some case in which our decision of each of the questions involved in some assertion is controverted, by different parties. E. G. Paul says, that the apostles preached “Christ crucified; to the Jews a stumbling-block, and to the Greeks, foolish
that Jesus, who had suffered an ignominious death, was the Messiah, the Saviour of the World, was a doctrine opposed both by Jews and Gentiles; though on different grounds, according to their respective prejudices: the Jews, who " sought after a Sign" (i. e. the coming of the Messiah in the clouds to establish a splendid temporal kingdom) were " offended” “ scandalized - at the doctrine of a suffering Messiah: the Greeks who “sought after Wisdom” (i.e. the mode of themselves exalting their own nature, without any divine aid) ridiculed the idea of a Heavenly Saviour altogether; which the Jews admitted. In logical language, the Gentiles could not comprehend the Predicate ; the Jews, denied the Copula.
It may be added, that in modern phraseology, the operations of corresponding prejudices are denoted, respectively by the words "paradox" (a " stumblingblock”) and " nonsense ;" (" foolishness”) which are often used, the one, by him who has been accustomed to hold an opposite opinion to what is asserted, the other, by him who has formed no opinion on the subject.
Such are the respective preparatory processes in these two branches of study. They are widely different; they arise from, and generate, very different habits of mind; and require a very different kind of training and precept.* The Pleader, or Controversialist, or, in short, the Rhetorician in general, who is, in his own province, the most skilful, may be but ill-fitted for Philosophical investigation, even where there is no observation wanted :when the facts are all ready ascertained for him. And again, the ablest Philosopher may make an indifferent disputant; especially, since the arguments which have led him to the conclusion, and have, with him, the most weight, may not, perhaps, be the most powvérful in controversy. The commonest fault,
however, by far, is to forget the Philosopher Sor Theologian, and to assume the Advocate, improperly. It is therefore of great use to dwell on the distinction between these two branches. As for the bare process of Reasoning, that is the same in both cases; but
* It is evident that the business of the Advocate and that of the Judge are in this manner opposed ; the one being to find arguments for the support of his client's cause ; the other, to ascertain the truth. And hence it is, that those who have excelled the most in the former department, sometimes manifest a deficiency in the latter, though the subject-matter, in which they are conversant, remains the same.
the preparatory processes which are requisite, in order to employ Reasoning profitably, these, we see, branch off into two distinct channels. In each of these, undoubtedly, useful rules may be laid down; but they should not be
confounded together. Bacon has chosen the Philosophical department of Philosophy; giving rules in his
Organon, not only for the conduct of experiments to ascertain new facts, but also for the selection and combination of known facts and principles, with a view of obtaining valuable Inferences ; and it is probable that a system of such rules is what some writers mean (if they have any distinct meaning) by their proposed “ Logic."
In the other department, precepts have been given by Aristotle and other Rhetorical writers, as a part of their plan. How far these precepts are
to be considered belonging to the present system,—whether “ method” is to be regarded as a part of Logic,—whether the matter of Logic is to be included in the system,—whether Bacon's is properly to be reckoned a kind of Logic; all these are merely verbal questions, relating to the extension, not of the Science, but of the
The bare process of Reasoning, i.e. deducing a Conclusion from Premises, must ever remain a distinct operation from the assumption of Premises, however useful the