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I believe no man remembers the birth of his reason but it is probable that his decisions are at first weak and wavering; and, compared with that steady conviction which he acquires in ripe years, are like the dawn of the morning compared with noon-day. We see that the reason of children yields to authority, as a reed to the wind; nay, that it clings to it, and leans upon it, as if conscious of its own weakness.
When reason acquires such strength as to stand on its own bottom, without the aid of authority, or even in opposition to authority, this may be called its manly age. But in most men, it hardly ever arrives at this period. Many, by their situaopportunity of cultiva
tion in life, have not the ting their rational powers. Many, from the habit they have acquired of submitting their opinions to the authority of others, or from some other principle which operates more powerfully than the love of truth, suffer their judgment to be carried along to the end of their days, either by the authority of a leader, or of a party, or of the multitude, or by their own passions. Such persons, however learned, however acute, may be said to be all their days children in understanding. They reason, they dispute, and perhaps write: but it is not that they may find the truth; but that they may defend opinions which have descended to them by inheritance, or into which they have fallen by accident, or been led by affection.
I agree with Mr Locke, that there is no study better fitted to exercise and strengthen the reasoning powers, than that of the mathematical sciences; for two reasons; first, Because there is no other branch of science which gives such scope to long and accurate trains of reasoning; and, secondly, Because in mathematics there is no room for authority, nor for prejudice of any kind, which may give a false bias to the judgment.
When a youth of moderate parts begins to study Euclid, every thing at first is new to him. His apprehension is unsteady: his judgment is feeble; and rests partly upon the evidence of the thing, and partly upon the authority of his teacher. But every time he goes over the definitions, the axioms, the elementary propositions, more light breaks in upon him: the language becomes familiar, and conveys clear and steady conceptions: the judgment is confirmed: he begins to see what demonstration is; and it is impossible to see it without being charmed with it. He perceives it to be a kind of evidence that has no need of authority to strengthen it. He finds himself emancipated from that bondage; and exults so much in this new state of independence, that he spurns at authority, and would have demonstration for every thing; until experience teaches him, that this is a kind of evidence that cannot be had in most things; and that in his most important concerns, he must rest contented with probability.
As he goes on in mathematics, the road of demonstration becomes smooth and easy: he can walk in it firmly, and take wider steps: and at last he acquires the habit, not only of understanding a demonstration, but of discovering and demonstrating mathematical truths.
Thus, a man, without rules of logic, may acquire a habit of reasoning justly in mathematics; and, I believe he may, by like means, acquire a habit of reasoning justly in mechanics, in jurisprudence, in politics, or in any other science, Good sense, good examples, and assiduous exercise, may bring a man to reason justly and acutely in his own profession, without rules.
But if any man think, that from this concession he may infer the inutility of logic, he betrays a great want of that art by this inference: for it is no better reasoning than this, That because a man may go from Edinburgh to London by the way of Paris, therefore any other road is useless.
There is perhaps no practical art which may not be acquired, in a very considerable degree, by example and practice, without reducing it to rules. But practice, joined with rules, may carry a man on in his art farther and more quickly, than prac tice without rules. Every ingenious artist knows the utility of having his art reduced to rules, and by that means made a science. He is thereby enlightened in his practice, and works with more assurance. By rules, he sometimes corrects his own
errors, and often detects the errors of others: he finds them of great use to confirm his judgment, to justify what is right, and to condemn what is wrong.
Is it of no use in reasoning, to be well acquainted with the various powers of the human understanding, by which we reason? Is it of no use, to resolve the various kinds of reasoning into their simple elements; and to discover, as far as we are able, the rules by which these elements are combined in judging and in reasoning? Is it of no use, to mark the various fallacies in reasoning, by which even the most ingenious men have been led into error? It must surely betray great want of understanding, to think these things useless or unimportant. These are the things which logicians. have attempted; and which they have executed; not indeed so completely as to leave no room for improvement, but in such a manner as to give very considerable aid to our reasoning powers. That the principles laid down with regard to definition and division, with regard to the conversion and opposition of propositions and the general rules of reasoning, are not without use, is sufficiently apparent from the blunders committed by those who disdain any acquaintance with them.
Although the art of categorical syllogism is better fitted for scholastic litigation, than for real improvement in knowledge, it is a venerable piece of antiquity, and a great effort of human genius. We
admire the pyramids of Egypt, and the wall of China, though useless burdens upon the earth. We can bear the most minute description of them, and travel hundreds of leagues to see them. If any person should with sacrilegious hands destroy or deface them, his memory would be had in abhorrence. The predicaments and predicables, the rules of syllogism, and the topics, have a like title to our veneration as antiquities: they are uncommon efforts, not of human power, but of human genius; and they make a remarkable period in the progress of human reason.
The prejudice against logic has probably been strengthened by its being taught too early in life. Boys are often taught logic as they are taught their creed, when it is an exercise of memory only, without understanding. One may as well expect to understand grammar before he can speak, as'to understand logic before he can reason. It must even be acknowledged, that commonly we are capable of reasoning in mathematics more early than in logic. The objects presented to the mind in this science, are of a very abstract nature, and can be distinctly conceived only when we are capable of attentive reflection upon the operations of our own understanding, and after we have been accustomed to reason. There may be an elementary logic, level to the capacity of those who have been but little exercised in reasoning; but the most important parts of this science require a ripe under