Classical Logic, Lesson 01

In every instance in which we reason, in the strict sense of the word, i.e. make use of arguments, (I mean real, valid arguments,) whether for the sake of refuting an adversary, or of conveying instruction, or of satisfying our own minds on any point, whatever may be the subject we are engaged on, a certain process takes place in the mind which is one and the same in all cases, provided it be correctly conducted.

Of course it cannot be supposed that every one is even conscious of this process in his own mind; much less, is competent to explain the principles on which it proceeds. This indeed is, and cannot but be, the case with every other process respecting which any system has been formed; the practice not only may exist independently of the theory, but must have preceded the theory. There must have been language before a system of Grammar could be devised; and musical compositions, previous to the science of Music. This, by the way, will serve to expose the futility of the popular objection against Logic, that men may reason very well who know nothing of it. The parallel instances adduced, show that such an objection might be applied in many other cases, where its absurdity would be obvious; and that there is no ground for deciding thence, either that the system has no tendency to improve practice, or that even if it had not, it might not still be a dignified and interesting pursuit.

One of the chief impediments to the attainment of a just view of Reasoning the nature and object of Logic, is the not fully understanding, or not sufficiently keeping in mind, the sameness of the reasoning process in all cases. If, as the ordinary mode of speaking would seem to indicate, Mathematical reasoning, and Theological, and Metaphysical, and Political, etc., were essentially different from each other, i.e. different kinds of reasoning, it would follow, that supposing there could be at all any such science as we have described Logic, there must be so many different species, or at least different branches, of Logic. And such is perhaps the most prevailing notion.

Nor is this much to be wondered at: since it is evident to all, that some men converse and write, in an argumentative way very justly on one subject, and very erroneously on another; in which again others excel, who fail in the former.

This error may be at once illustrated and removed, by considering the parallel instance of Arithmetic; in which every one is aware that the process of a calculation is not affected by the nature of the objects, whose numbers are before us: but that (e.g.) the multiplication of a number is the very same operation,  whether it be a number of men, of miles, or of pounds; though nevertheless persons may perhaps be found who are accurate in the results of their calculations relative to natural philosophy, and incorrect in those of political economy, from their different degrees of skill in the subjects of these two sciences; not surely because there are different arts of Arithmetic applicable to each of these respectively.

Others again, who are aware that the simple system of Logic may be applied to all subjects whatever, are yet disposed to view it as a peculiar method of reasoning, and not, as it is, a method of unfolding and analyzing our reasoning: whence many have been led to talk of comparing Syllogistic reasoning with Moral reasoning; taking it for granted that it is possible to reason correctly without reasoning logically; which is, in fact, as great a blunder as if any one were to mistake grammar for a peculiar language, and to suppose it possible to speak correctly without speaking grammatically. They have in short considered Logic as an art of reasoning; whereas it is the art of reasoning; the logician’s object being, not to lay down principles by which one may reason, but, by which all must reason, even though they are not distinctly aware of them: to lay down rules, not which may be followed with advantage, but which cannot possibly be departed from in sound reasoning.

These misapprehensions and objections being such as lie on the very threshold of the subject, it would have been hardly possible, without noticing them, to convey any just notion of the nature and design of the logical system.

Source: Whately, Richard.  Elements of Logic (1870). Book I, Chapter 1, Section 1.

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