It denotes sometimes the mere statement of _a general fact_, or the result of a comprehensive generalization, founded on the observation and comparison of many particular facts; it denotes at other times _the force or power_, whatever that may be, which produces any given set of phenomena.

The "law" of gravitation, for example, is often used to denote nothing more than the _general fact_, ascertained by experience, that all bodies near the surface of the earth tend to its centre with a velocity proportioned directly to their mass, and inversely to the square of their distance; and when it is employed in _this_ sense, it determines nothing as to the "cause" which is in operation,--it affirms merely a fact, or a fact reduced to a formula, and confirmed by universal experience.

But it is often transferred, at least mentally and almost perhaps unconsciously, to denote some "power" which is instinctively supposed to be in operation when any change is observed,--a "power" which may be conceived of, either as a _property_ inherent in mind or in matter, or as a _force_, such as the Divine volition, acting upon it _ab extra_; and it is only in the latter of these two senses, as denoting a "cause," properly so called, and not a mere fact or law, that it can be applied to account for any phenomenon.
In like manner, the "laws of motion" are merely the generalized results of our experience and observation relative to the direction, velocity, and other phenomena of moving bodies; but "motion," although it is regulated, is not produced, by these laws; it depends on a "cause," whatever that may be, which is not only distinguishable, but different from them all.

Yet when we speak of the "laws of motion," we may imperceptibly include, in our conception of them, that _force_ or _power_ which impels the body, as well as the mere _law_ or _rule_ which regulates its movements.

It were a mere unprofitable dispute about words, did we entertain and discuss the question, whether the import of the term "law" might not be so extended as to include under it _powers_, _properties_, and _causes_, as well as the _rules_ and _conditions_ of their operation: for, even were this question answered in the affirmative, there would still be room for a real distinction between the two, and there could be no reason for saying that the knowledge of "causes," as distinguished from "laws," is wholly inaccessible to the human faculties.