of precision in applying it*, and he sometimes includes, under the term, the formation or deduction of the general law as well as the examination of instances. Newton has, I think, fallen into an ambiguous use of the word in a passage which occurs at the conclusion of his "Optics." While the extract now presented will furnish an instance in point, it will exemplify also the manner in which observation and experiment are commonly, and in my view inaccurately, distinguished.

"Analysis [in natural philosophy] consists in making experiments and observations, and in drawing conclusions from them by induction, and admitting of no objections against the conclusions but such as are taken from experiments or other certain truths. For hypotheses are not to be regarded in experimental philosophy. And although the arguing from experiments and observations by induction be no demonstration of general conclusions; yet it is the best way of arguing which the nature of things admits of, and may be looked upon as so much the stronger by how much the

* "Inductio enim quæ procedit per enumerationem simplicem res puerilis est, et precario concludit, et periculo exponitur ab instantia contradictoria et plerumque secundum pauciora quam par est, at ex his tantummodo quæ præsto sunt pronunciat. At inductio, quæ ad inventionem et demonstrationem scientiarum et artium erit utilis, naturam separare debet per rejectiones et exclusiones debitas, ac deinde, post negativas tot quot sufficiunt, super affirmativas concludere." - Nov. Org., lib. i. aph. cv.

induction is more general: and if no exception occur from phenomena, the conclusion may be general."*

In the first and second use of the term in this passage, the intention of the writer was manifestly to characterise the drawing of the conclusion, although the meaning is not very happily brought out, since we cannot with propriety speak of drawing conclusions by means of the operation itself, or of any other operation. In the last use of the term, he evidently meant to characterise the comprehensiveness of the preliminary observation.

I have already cited Mr. Stewart as using the term induction, to denote the course of investigation preparatory to the formation of a general law; but in another passage, where he describes the method of induction, he includes also the final inference.

"Wherever," he says, "an interesting change is preceded by a combination of different circumstances, it is of importance to vary our experiments in such a manner as to distinguish what is essential from what is accessory; and when we have carried the decomposition as far as we can, we are entitled to consider this simplest combination of indispensable conditions as the physical cause of the event. "When by thus comparing a number of cases,

* Dr. Johnson gives the greater part of this passage in his Dictionary, to support his second definition of the term, borrowed from Watts's Logic, viz. "Induction is when from several particular propositions we infer one general."

agreeing in some circumstances, but differing in others, and all attended with the same result, a philosopher connects, as a general law of nature, the event with its physical cause, he is said to proceed according to the method of induction. This, at least, appears to me to be the idea which, in general, Bacon himself annexes to the phrase; although I will not venture to affirm that he has always employed it with uniform precision. I acknowledge also that it is often used by very accurate writers, to denote the whole of that system of rules of which the process just mentioned forms the most essential and characteristical part." *

It appears then, from the authorities I have cited, that there are at least three different modes of employing the term; viz. to denote,

1. The investigation of facts, preparatory to the formation of a general law;

2. The mere inferring of the general law from the facts brought together by such investigation; 3. The two preceding processes combined.

The first of these acceptations appears to me to be the most conformable to the general usage of philosophical writers, and for that reason the most convenient to adopt.

If this discussion should appear to turn on a mere question of phraseology, it must still be allowed, that to settle the meaning of so important a word

* Elements, vol. ii. p. 348.

as Induction is exceedingly desirable and worth some pains. At present it may be doubted whether any two men of science, taken at random and not being technical logicians, would give the same definition of it.

My principal aim, however, in the present chapter has been, in consonance with the subject of my treatise, to point out how far reasoning is concerned in this important combination of intellectual operations. I have accordingly endeavoured to show, that induction cannot be carried on without a continual intermixture of inferences with observation ; and that the result to which the whole converges, is the formation of a general law, -itself an act of contingent reasoning.

CHAP. XI.

RULES FOR GUIDING THE OPERATIONS OF REASONING, AND ESPECIALLY THE RULES OF THE SCHOLASTIC LOGIC.

A TRUE theory of the reasoning processes, or, in other words, a thorough comprehension of their character, although fortunately not essential to the right performance of the acts, may be expected to assist us in some degree to arrive at correct conclusions; but will perhaps be more especially serviceable in preventing that misdirection of our powers, and that waste of attention on wrong objects, which are the usual results of a false theory on an important subject.

It must also tend to inspire us with confidence in our deductions, and with fearlessness in submitting them to the examination of others, in proportion as it enables us to discern the character of every link in the chain of argumentation.

Whether, nevertheless, such an insight into the nature of the processes will afford any formal rules to guide us in the performance of them, and whether any such rules are needed, seem to be points not equally clear.

From the preceding exposition of the subject, it