CHAP. V. perience we have had in very early life of our own power to produce certain effects. But the belief, that no event can happen without an efficient cause, cannot be derived from experience. We may learn from experience what is, or what was, but no experience can teach us what neceffarily must be.

In like manner, we probably derive the conception of pain from the experience we have had of it in ourselves; but our belief that pain can only exist in a being that hath life, cannot be got by experience, because it is a neceffary truth; and no neceffary truth can have its attestation from experience.

If it be so that the conception of an efficient cause enters into the mind, only from the early conviction we have that we are the efficients of our own voluntary actions, (which I think is most probable) the notion of efficiency will be reduced to this, That it is a relation between the cause and the effect, fimilar to that which is between us and our voluntary actions. This is furely the most diftinct notion, and, I think, the only notion we can form of real efficiency.

Now it is evident, that, to constitute the relation between me and my action, my conception of the action, and will to do it, are effential. For what I never conceived, nor willed, I never did.

If any man, therefore, affirms, that a being may be the efficient cause of an action, and have power to produce it, which that being can neither conceive nor will, he speaks a language which I do not understand. If he has a meaning, his notion of power and efficiency must be effentially different from mine; and, until he conveys his notion of efficiency to my understanding, I can no more affent to his opinion, than if he should affirm, that a being without life may feel pain.

It

It seems, therefore, to me moft probable, that fuch beings only CHAP. VI. as have fome degree of understanding and will, can poffefs active power; and that inanimate beings must be merely paffive, and have no real activity. Nothing we perceive without us affords any good ground for afcribing active power to any inanimate being; and every thing we can difcover in our own conftitution, leads us to think, that active power cannot be exerted without will and intelligence.

I'

CHA P. VI.

Of the efficient Caufes of the Phanomena of Nature.

F active power, in its proper meaning, in its proper meaning, requires a subject endowed with will and intelligence, what shall we fay of those active powers which Philofophers teach us to afcribe to matter; the powers of corpufcular attraction, magnetifin, electricity, gravitation, and others? Is it not univerfally allowed, that heavy bodies defcend to the earth by the power of gravity; that, by the fame power, the moon, and all the planets and comets, are retained in their orbits? Have the most eminent natural Philofophers been impofing upon us, and giving us words inftead of real caufes ?

In answer to this, I apprehend, that the principles of natural philosophy have, in modern times, been built upon a foundation that cannot be fhaken, and that they can be called in question only by those who do not understand the evidence on which they stand. But the ambiguity of the words cause, agency, active power, and the other words related to these, has led many to understand them, when ufed in natural philofophy, in a wrong fense, and in a sense which is neither neceffary for establishing

CHAP. VI. the true principles of natural philofophy, nor was ever meant by the most enlightened in that science.

To be convinced of this, we may observe, that those very Philofophers who attribute to matter the power of gravitation, and other active powers, teach us, at the fame time, that matter is a fubftance altogether inert, and merely paffive; that gravitation, and the other attractive or repulfive powers which they afcribe to it, are not inherent in its nature, but impreffed upon it by fome external caufe, which they do not pretend to know, or to explain. Now, when we find wife men afcribing action and active power to a substance which they exprefsly teach us to con-fider as merely paffive and acted upon by fome unknown cause, we must conclude, that the action and active power afcribed to. it are not to be understood ftrictly, but in fome popular fenfe.

It ought likewise to be observed, that although Philofophers, for the fake of being understood, must speak the language of the vulgar, as when they fay, the fun rifes and fets, and goes through all the figns of the zodiac, yet they often think differently from the vulgar. Let us hear what the greateft of natural Philofophers fays, in the 8th definition prefixed to his Principia, "Voces autem attractionis, impulfus, vel propenfionis cujufcunque in centrum, indifferenter et pro fe mutuo promifcue ufurpo; has voces non phyficè fed mathematicè confiderando. "Unde caveat lector, ne per hujus modi voces cogitet me fpe"ciem vel modum actionis, caufamve aut rationem phyficam, "alicubi definire; vel centris (quæ funt puncta mathematica) "vires vere et phyfice tribuere, fi forte centra trahere, aut vires centrorum effe, dixero."

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In all languages, action is attributed to many things which all men of common understanding believe to be merely paffive; thus we fay, the wind blows, the rivers flow, the fea rages, the fire burns, bodies move, and impel other bodies.

Every

Every object which undergoes any change, must be either ac- CHAP. VI tive or paffive in that change. This is felf-evident to all men from the first dawn of reafon; and therefore the change is always expressed in language, either by an active or a passive verb. Nor do I know any verb, expreffive of a change, which does not imply either action or paffion. The thing either changes, or it is changed. But it is remarkable in language, that when an external cause of the change is not obvious, the change is always imputed to the thing changed, as if it were animated, and had active power to produce the change in itself. So we say, the moon changes, the fun rifes and goes down.

Thus active verbs are very often applied, and active power imputed to things, which a little advance in knowledge and experience teaches us to be merely paffive. This property, common to all languages, I endeavoured to account for in the fecond chapter of this Effay, to which the reader is referred.

A like irregularity may be observed in the use of the word fignifying cause, in all languages, and of the words related to it.

Our knowledge of caufes is very fcanty in the most advanced state of fociety, much more is it fo in that early period in which language is formed. A ftrong defire to know the causes of things, is common to all men in every state; but the experience of all ages fhews, that this keen appetite, rather than go empty, will feed upon the husks of real knowledge where the fruit cannot be found.

While we are very much in the dark with regard to the real agents or causes which produce the phænomena of nature, and have, at the same time, an avidity to know them, ingenious men frame conjectures, which thofe of weaker understanding take for truth. The fare is coarfe, but appetite makes it go down.

CHAP. VI.

Thus, in a very ancient fyftem, love and ftrife were made the caufes of things. PLATO made the caufes of things to be matter, ideas, and an efficient architect. ARISTOTLE, matter, form, and privation. DES CARTES thought matter, and a certain quantity of motion given it by the Almighty at first, to be all that is neceflary to make the material world. LEIBNITZ conceived the whole universe, even the material part of it, to be made up of monades, each of which is active and intelligent, and produces in itself, by its own active power, all the changes it undergoes from the beginning of its existence to eternity.

In common language, we give the name of a cause to a reason, a motive, an end, to any circumstance which is connected with the effect, and goes before it.

ARISTOTLE, and the schoolmen after him, distinguished four kinds of caufes, the efficient, the material, the formal, and the final. This, like many of ARISTOTLE'S diftinctions, is only a diftinction of the various meanings of an ambiguous word; for the efficient, the matter, the form and the end, have nothing common in their nature, by which they may be accounted fpecies of the fame genus; but the Greek word which we translate cause, had these four different meanings in ARISTOTLE's days, and we have added other meanings. We do not indeed call the matter or the form of a thing its caufe; but we have final caufes, inftrumental caufes, occafional caufes, and I know not how many others.

fo

Thus the word cause has been so hackneyed, and made to have many different meanings in the writings of Philofophers, and in the discourse of the vulgar, that its original and proper meaning is loft in the crowd.

With regard to the phænomena of nature, the important end. of knowing their causes, befides gratifying our curiofity, is,

that