be false; and it cannot be proved otherwise till all science is perfected; but the burden of finding and demonstrating an exception lies with its opponents, who might thus confute or limit it. Such systems, however, as that of Boscovich, start with hypotheses, far-fetched, and opposed to all the preconceived opinions and prejudices of mankind; and, but for the prevalence of the idea that prejudices ought to be abandoned, instead of being carefully examined, could never have worked themselves into notice, without the preliminary overthrow and new establishment of almost all the fundamental principles of science. With respect to Gravity, Repulsions, and the like, as I shall speak of them more fully presently, I shall here merely point out that it should be particularly noted, that they are phenomena with which we are not thoroughly acquainted; and with whose causes we are not acquainted at all. We cannot, therefore, legitimately build an hypo

G

thesis upon them; and if we reason from them, we reason from the unknown against the known, a method of proceeding grossly absurd and altogether inadmissible.

Not only are the causes, which produce any effect, the objects of philosophical research; but the manner, in which those causes act, is an object of such importance, as almost to have superseded the inquiry into Causation itself. In modern experimental Philosophy it is often laid down as a maxim, that the laws of nature are the only proper objects of human inquiry and all investigation of causes is stifled by the dogma, which maintains, that the human faculties are incapable of investigating their na

ture.

There is scarcely a term in science, so obscure, and so much abused, as this word Law. It is said to be a Law, That the three angles of a triangle are equal to two right angles-That certain

substances crystallize in certain forms -That all stones gravitate to the earth -That gravity varies inversely as the square of the distance. It is a law of the understanding, that we are convinced by demonstration; and of the affections, that we love our friends. These different applications of the word agree in this, that they are all general propositions; and most of them are general facts. The word law sometimes relates to the Classification of objects in Space, or of events in Time, to the phenomena of Causation, Material, Formal, and Efficient, indiscriminately, and frequently to the Manner in which these causes act: the latter of which is, perhaps, its most appropriate meaning. But the word Law has even a more extended signification, and is not unfrequently substituted for the Cause itself: and among the generality of men, who have thought somewhat, but not deeply, upon such matters, this usage of the term, with respect to

the phenomena of gravity, is even the most prevalent of all: and, though never entertained for a moment by those who have paid due attention to the subject, it has become a form of speech, so common, that the most eminent philosophers* occasionally fall into it.

If it be not advisable, altogether to discard a term, so generally abused, it might advantageously be confined to the manner or rule according to which a Cause acts, or an Object is constructed, whether by immediate or secondary

* Dr. Young sometimes uses it in this significa tion, and Sir J. Herschel has inadvertently fallen into the same manner of speaking; "In the theory of gravitation," says he, in his celebrated Discourse, "the Law is all in all, applying itself at once to the materials, and directly producing the result." What produces the result? The Law? The laws of nature,' says Dr. Reid, in his maturest work, are the rules, according to which effects are produced: but there must be a cause, which operates according to these rules. The rules of navigation never steered a ship'-nor the law of gravity a planet.

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means.

Human agents act in a manner capricious and uncertain: but the invariable constancy, observable in all the works of the Creator, enables us to look forward with certainty to the result: and the manner according to which it is performed is so determinately appointed, and as it were preordained, that we may not improperly denominate it a LAW.

Natural Philosophy, then, relates to the Material Substances which compose the universe: which Substances are known to us only by their Qualities as they coexist in Space, or their Forces, actions, motions, or accidents, as they operate in Time. Of these two great branches, Natural History is the mere classification, into genera and species, and description. Causation equally relates to both, and is the investigation of the nature and continuity of the Material, Formal, and Efficient Causes, the Chain of Being existing in Space, and the Chain