I think none but a Sceptic will deny the Great Mischief of Scepticism, which at once defeats the best Means, and the best End of Human Nature; and I am of Opinion, this one Notion of Mr. Lock's has no little Tendency that Way:

Ep. Partis primæ, p. 114.

Des Cartes lays it down for an Axiom, Nec alia funt quæ à Deo fieri non posse dicuntur, quam quod repugnantiam involvunt in conceptu, hoc est, quæ non funt intelligibilia. So that what is not poffible any Way to be conceiv'd, argues as much a Repugnancy in Conception, as what is contradictory: Not that this is any Prejudice to the Belief of Things that are above our Conception, upon an Authority which we do conceive to be fufficient; but that, in our own Reasoning upon Things, we must reject, as Falfhood, what is impoffible to be understood, as Truth: For indeed the very Nature of a Contradiction lyes in this, That it is a thing impoffible to be

conceiv'd.

Whoever breaks in upon this Rule, destroys the only Criterion we have of Truth, which must confift in a clear and diftinct Perception, or, with a late Author, Conception, of it; that is, it must be the Object of our Understanding, tho'

Medicina Ment. Pars 2.

P. 42.

not

not of our Imagination; and if this Rule ever fails us in one Inftance, there can be no Reason given why it fhou'd hold in any: Whereas, if, according to the Cartefan Principles, the Veracity of God is concern'd, it can, like that, never fail us: But to wave all circular Proof, as indeed all pretended Proof must be in this Cafe, I fay, That as every particular Science has its First Principles and Axioms upon which it is built; fo this is the First Principle and Axiom of all Sciences, the Truth of our Faculties. To deny this, in any one Instance, is in effect to deny it in all, which does not indeed lead us to Univerfal Scepticism, (for that is Nonfence and Contradiction, to deny all Truth, and at the fame time to believe one's own Affertion to be true;) but it leaves us nothing of certainty, excepting this one thing, that God have deceiv'd us: may A weak Principle, God knows, for the Reasonable Faculty, the Perfection and Happiness of Human Nature, to reft upon. That the Author forefaw this Confequence, I am as far from believing, as I am that he can difprove it.

In the mean time I conclude, that Cogitation and Extenfion are found, upon the Comparison, to be inconfiftent and incompatible in one and the same Substance à

and

and that this their Inconfiftency in one, is as full an Evidence of their appertaining to two Substances, as demonftrative Knowledge will bear. But for the farther clear-, ing of this Point, we will particularly confider, Whether Cogitation in it felf does not require an Immaterial Subject; and next, Whether a Phyfically extended Substance is in it felf capable of Cogitation. This indeed is already absolutely determin'd by our comparing the two Properties together; but will receive farther Light, by comparing the Property in difpute, with each of thofe Subjects that lay claim to it.

SECT. VI.

Of Cogitation, (as in Man) requiring an Immaterial Substance.

FIR

IRST then, Let us compare our Faculty of Cogitation with an Immate rial Subftance, (the Principle establish'd Sect. III.) and fee whether it does not properly belong unto it.

'Tis certain, all our Ideas are converfant about Things, and the Relations of Things.

have no clearer Idea of the Part, than I have of the whole of an extended Mafs, without the precedent Idea of Extenfion : And therefore to demand wherein fuch fimple Ideas confift, is the fame thing, as to demand a Proof of First Principles; fo that this Piece of Ignorance is no Reason at all why God can, if he pleases, Ibid. fuperadd to Matter the Faculty of Thinking; of which, more afterward.

2

But to return, and to prove that this Idea of Senfation does, of it felf, difcover fome thing Immaterial in us; let us obferve how it is imprefs'd upon us, in that Inftance of our drawing near a Fire; which by degrees warms us, and fo gives us the fenfe of Pleasure, 'till continu'd, heats us exceffively, and then gives Pain. It is certain that both thefe, as Mechanical Motions in our Organ, differ only in Degree; and it is as certain that the two Ideas differ as Con- ' traries, and do, as the Logicians fpeak, se mutuo tollere. In this Cafe, when the Idea of Pain begins, that of Pleasure is utterly extinct. But how Motion communicated from the fame Object, upon the fame Organ, and in the fame manner, excepting only the least Degree of Celerity added, fhou'd produce Ideas fo perfectly contra dictory to each other, as the one to make us happy, the other unhappy, antecedently

to

to our Reasoning upon them; is a Mechanical Mystery indeed: For, allowing that one Part of Matter can ftrike an Idea into another, because we have not yet directly prov'd the Contrary, yet, according to that Hypothefis, it ought to be done in a Mechanical Way; and then it wou'd follow, That we shou'd live and dye either altogether in Pleasure, or altogether in Pain. Our Reason and Experience might distinguifh the Degrees, and fo make us avoid what will be finally noxious to us; but the bare Ideas of Senfation cou'd give us no Warning, nor be of any Use to this Purpose.

But now the Suppofition of an Immaterial Subftance united to our Material, and so united, as to be affected with all the various Motions the other receives; and fo affected, as upon a certain Degree of disorderly Motions in the Body, to be perfectly loofen'd and difunited from it, will rationally account for the wide Difference of our Senfations. No wonder if that which is agreeable to the Natural Motions of our Body causes Pleasure in our Mind, fo clofely and perfonally joyn'd with it; and that Motion which, in a higher degree, will cause a Separation, caufes an uneafy Sense in a lower; and makes, as it were, a new Modification of the Mind, attending always