should be suspected that I misunderstand him, then, I say, attraction must be either the cause or the effect; if it be the effect, then to affirm that the rise of the water is manifestly owing to attraction, is but to say in other words, that the effect is manifestly owing to the effect. If it be taken for the physical cause, and I should deny the reality of its existence, how would you prove it? you will refer me perhaps to the phænomenon, for that is the common way of reasoning, and tell me I cannot help seeing it. But attraction is not the phænomenon; it is Mr. Rowning's explanation of it. The phæ nomenon, evident to sense, is only the rising of the water; the attraction of the glass, not evident either to sense or reason, is set down as the cause to which it is manifestly owing: and this cause, as the author hath affirmed in another place, is a term used only to signify an effect.

The nature of attraction is such, that we have succeeded but very indifferently in this part of our inquiry, as I could plainly foresee we should. The subject is involved in an obscurity, either studied or unavoidable; and in all the passages I have been able to collect and compare, there is something that

1

appears

appears like a slight of hand, whereby the effect is shifted into the place of the cause, As I am unable to draw any doctrine from the whole with precision, it will be best to introduce the authors giving their verdicts in their own words, and leave the reader to his own judgment,

Sir Isaac Newton.

"acts."

Dr. Friend.

"Gravity exists and

"In explaining gravity,

"Newton has demonstrated it to arise from "an attractive force."

M. Maupertuis. "It should be remem"bered, in justice to Sir Isaac Newton, he "has never considered attraction as an erplanation of gravity. He considers it not "as a cause, but as an effect."

Mr. Cotes. ፡፡

"of causes.

Gravity is the most simple

Dr. Clarke. "It has often been distinct

ly declared, that by the term attraction,

we do not mean to express the cause of "bodies tending toward each other, but "barely the effect, the effect itself, the pha"nomenon, or matter of fact."

Dr. Desaguliers. "Attraction seems to "be settled by the great Creator as the first "of second causes.”

Mr.

Mr. Rowning. "When we use the term "attraction, we do not determine the phy"sical cause of it, but use it to signify an 'effect: nevertheless, to attraction effects are manifestly owing."

Sir Isaac Newton.

"There are agents in "nature able to make the particles of bodies "stick together by very strong attractions, " and it is the business of experimental philosophy to find them out."

Dr. Desaguliers. "We are not solicitous "about the cause of attraction."

Dr. Friend. "I believe attraction will "always be occult."

This is the result of my inquiry: and if any person should be so inclined, he is welcome to lay all the blame upon my want of understanding. But, if these learned men, who are all vindicating the self-same principles of philosophy, had no clear ideas of what they affirmed, and could not understand one another; it is no wonder, if the world should be at some loss to understand them.

CHAP.

CHAP. III.

Attraction, a material force in the judgment of some authors; an immaterial force in the judgment of others; and sometimes both one and the other in the judgment of the same author.

WE have yet a third question to settle,

viz. whether attraction be a material

force, or an immaterial one? and here we shall have the same scene as before; this point being left equally undetermined with the former. Indeed nothing can be more evident, than that Sir Isaac Newton, great as he was, hath offered to the world his thoughts on a question of much importance, and taken both sides of it. It is disagreeable to me to say this; but it must be said, because it is certainly true; and I cannot go forward without saying it. This, as we shall find, has divided his followers; and their disputes with each other in regard to first-principles and fundamentals, have as great an appearance of fallibility and uncertainty, as other disputes used to have, be

fore

fore the science of natural philosophy was. enriched with demonstration: of which I shall exhibit a notable instance, from the writings of the celebrated Mr. Maclaurin, and his antagonist, the author of an Inquiry into the Nature of the Human Soul.

But first let us attend to Sir Isaac himself. There is a passage in his Optics, wherein he allows, that what he imputes to attraction may be performed by impulse *. Dr. Clarke, in his notes on Rohault, cites this passage; and lest we should take the impulse here spoken of, to be that of some intervening matter, he inserts, by way of commentnon utique corporeo-† declaring, that this impulse is not corporeal; or, in other words, that it is not the impulse of any material. agent. We have the same sentiment from him upon another occasion:-" It is now "allowed on all hands, that gravity does "not depend on the action of the air or "æther, but is a primigenial, innate, and "unchangeable affection of all matter" This is in answer to the great Dr. Wallis, who was of another mind. He suspected

* Page 351.

+ Page 51.

that

Verum cum jam in confesso sit, gravitatem non ab aere athereve pendere, sed esse primigeniam, connatam, immutabilemque materiæ affectionem, &c. p. 61.