That syllogistic form which is properly called Inductive (],ray) is explained, though very briefly, by Aristotle (A nalyt. Prior., ii. 23; Topic., i. 12), and is not confounded by him with the material induction of a general law or rule from the examination of a number of particular cases of a like kind." If we wish to prove syllogistically the mortality of a given individual John, we say— All men arc mortal; John Is a man ; • Therefore John Is mortal.
Now this conclusion is necessary, because "John" is contained in "all men." But suppose we wish to prove our primary proposition, that " all men are mortal," what is the process that wo must follow T We may affirm mortality of all men who have died, but we cannot affirm it of all who are living and who shall live, for that is the thing to be proved. This is a case in which there can be no logical, that is, no necessary conclusion.
Dr. Whitely says (p. 229) "that in the process of reasoning by which we deduce from our observation of certain known cases an infer ence with respect to unknown ones, we are employing a syllogism in Barbara with the major premise suppressed; that being always sub stantially the same, as it asserts 'that whatever belongs to the individual or individuals we have examined, belongs to the whole class under which they come.' " And be further says that induction, "so far forth as it is an meet (which has previously, in the same work (p. 55), been defined to be a syllogism when regularly expressed'), may of course be stated syllogistically; but so far forth as it is a process of inquiry to-obtain the premises of that argument, it is of course out of the province of logic." But a syllogism will be equally good (p. 14) if we substitute arbitrary symbols for the terms, without any regard to the things signified by them ; and (p. 23) " every conclusion is deduced from two other propositions or premises." Thus so-called induction then, stated syllogistically, turns out to be nothing different from a proper syllo gism : if the premises are true, the conclusion is necessarily true. The syllogism then has done nothing, and it leaves the process of inquiry precisely where it was before the induction was put into this so-called syllogistic form.
This mistake requires a few more words, as it has been declared to be "a just, and, so far as we are aware, an original remark ; and its consequences are extremely important." ( Westminster Revive, No. 17, p. 1(S9).
The deducing an inference from facts investigated and collected is said to be an argumentative process, and. like other arguments (that is, syllogisms), capable of being syllogistically expressed. If it is a syllo gistic process, it is undoubtedly susceptible of the strict syllogistic form. Now this so-called inference is the making a universal affirma
tion founded on a number of particulars; and if it is a syllogism, the universal affirmation is the conclusion ; and if it is a syllogism, the conclusion is necessary. The conclusion is by the supposition a con clusion from certain known things as to other unknown things; and the universal conclusion is, that something is true of the unknown things which is known to be true of the known ones; in other words, that this something is true both of the known and the unknown things. Now in order to attain this syllogistic conclusion, it is said that we employ a syllogism, in which the major premiss is of this form : everything which is true of the known is true of the unknown, or everything which is true of the known is true of the known and the unknown.
To take Dr. Whately's own example :—" from an examination of the history of several tyrannies, and finding that each of them was of short duratiou, we conclude that the same Is likely to he the case with all tyrannies." And it is said that in such syllogisms as these, we assume "that ichaterer belongs to the individual or individuals that we are examining belongs to the class under which they come." Now this universal affirmation is a proposition to be proved in some way or other. If it be assumed, it ix the major of a deductive syllogism, and the conclusion is logically necessary, and also true, if the major is true.
But bow is this major to be established, by virtue of which we are to have a logical illation and a true conclusion ? It is admitted that in induction, properly so-called, a general material truth is to be affirmed by virtue of particular facts being investigated and known. But if we affirm some proposition which is more general than and compreheuds that which we wish to establish, and then so construct our syllogism that the conclusion shall be a logical inference, it cannot be a true one unless we establish this more general premiss. But the object of the true induction is to establish the general truth from particular facts that are known and investigated. If, in the case supposed, the syllogism is valid, the particular facts are useless ; the conclusion is logically good, and it becomes materially true when the more general proposi tion is established which contains the conclusion. But it is not the object of the investigation and collection of facts to establish a proposition different from and more general than that for the establishment of which the facts are investigated and collected ; in other words, it is not the matter in hand to investigate and collect facts for a particular purpose, and then not to use them for that purpose.