When now the systematic philosopher applies himself to ac.count for, and range in regular order, the various phenomena referable to matter and motion, his object being merely explanation and arrangement, he naturally sets out from common and familiar notions, and principles which no one doubts of, and applies all his powers to tracing out from their operation some explanation of the phenomena in question."Reasoning on these familiar notions, from a few particulars, and perhaps some generally admitted maxims, he rises immediately to the most general conclusions, and from their fixed and immutable truth judges all other particulars.If some of them seem contrary to his theory, he employs his ingenuity to explain them away, or to make them appear coincident, or removes the difficulty by terming them exceptions; while such particulars as are not opposed to his principles, are laboriously and artfully arranged, according to his system." (139) Omitting, for the present, the consideration of what he actually accomplishes, let us attend to that wherein he fails.
The familiar notions of the common observer become his connecting media, and tie pretends to account for the whole phenomena of matter and motion, on the principles, as he calls them, of gravity, levity, natural and violent motion.Now it is obvious that, by this application of the terms, he completely, though imperceptibly, changes their meaning.As employed by the man of practical observation, though perhaps somewhat confusedly conceived, they necessarily and really mean nothing more, than certain known consequences, the results of some unknown laws or powers regulating the system of things.
As employed by the systematic philosopher, they, on the contrary, are assumed to be the very laws, powers, or principles, themselves governing and sustaining the mundane system.The change in signification is not perceived, for the generality of mankind are incapable of any thing like metaphysical accuracy of conception, and are led away very easily by the fallacies of language.
Its consequences, however, are important, for if we understand by science the knowledge of the real laws of nature, -- the laws governing tho general system,- this assumption completely diverts from their discovery, for it induces the belief that they are already reached.It seems to be on this account, that Lord Bacon so often points out the errors arising from the hasty adoption of preconceived notions, "anticipationes," the greater part of the first book of the "Novum Organum" consisting, in fact, of an exposition of them.(140) Acuteness of reasoning, and reach of thought are thus, he observes, rendered useless, for they come too late.The place for them is in examining and weighing experiences, and from these deducing first principles.(141) If this be omitted no subtilty of definition, or logical accuracy of deduction can avail.The remedy is too weak for the evil, nor is itself void of evil.
The instrument employed is not fitted to reach the depths of nature, and, by catching after what it cannot attain to, is rather calculated to establish error, than to open up the road to truth.The definitions may indeed sufficiently mark the sense, and from these definitions the conclusions insisted on may be logically deduced, nevertheless there is this of deceit in the procedure, ttmt the notions themselves may be taken up hastily, and carelessly from common observation, and may, therefore, be confused, and loose, and afford no solid foundation for the edifice which it is attempted to rear." (142) Such was the system of physics which the Greeks raised from these principles.
Being built on common and familiar notions; a conversion of general practical rules into speculative general principles, whatever its merits were as a system, explaining according to popular notions, the various phenomena of nature, and ranging these in regular order, it had no pretensions to merit as expository of the real science of nature.
It was not until attention was directed to the examination of things before supposed to be known, -- motion, natural and violent, gravity, levity, etc.-- and inquiry made into the principles by which they themselves are regulated, the laws, that is to say, according to which the phenomena, so denominated, are produced, that a beginning was given to real science.
Then the laws regulating the universal system were gradually unfolded, and things seemingly forever hidden in the depths of the immensity of space and time, brought clearly before the intellectual ken of man.
As in the system of things making up the world of mere matter, certain terms are employed to denote general facts and rules, which experience has taught, so, in the compound system of men and things making up the world of civilized life, certain other terms are employed to denote the general facts and rules, which experience also has there taught; and as in a department of the one, we have heaviness, lightness, natural, and violent motion, etc.; so in a department of the other we have capital, value, profit, a due regard to self-interest, kc.; in both, too, it is to be observed, such popular and familiar phrases and notions, correctly interpreted, express, not the general laws of the system, but the usual and expected results of those laws.
