the way! From how many more did he not warn the wise to withhold their curiosity, by his bold and fruitless attempts to burst the barriers of the invisible world!

The best éloge of Leibnitz is furnished by the literary history of the eighteenth century;-a history which, whoever takes the pains to compare with his works, and with his epistolary correspondence, will find reason to doubt, whether, at the singular era when he appeared, he could have more accelerated the advancement of knowledge by the concentration of his studies, than he has actually done by the universality of his aims; and whether he does not afford one of the few instances to which the words of the poet may literally be applied:

"Si non errâsset, fecerat ille minus."

SECTION III.

Of the Metaphysical Speculations of Newton and Clarke.-Digression with respect to the System of Spinoza.-Collins and Jonathan Edwards.-Anxiety of both to reconcile the Scheme of Necessity with Man's Moral Agency.-Departure of some later Necessitarians from their views.†

THE foregoing review of the philosophical writings of Locke and of Leibnitz naturally leads our attention, in the

* See Note (F f.)

In conformity to the plan announced in the preface to this Dissertation, I confine myself to those authors whose opinions have had a marked and general influence on the subsequent history of philosophy; passing over a multitude of other names well worthy to be recorded in the annals of metaphysical science. Among these, I shall only mention the name of Boyle, to whom the world is indebted, besides some very acute remarks and many fine illustrations of his own upon metaphysical questions of the highest moment, for the philosophical arguments in defence of religion, which have added so much lustre to the names of Derham and Bentley; and, far above both, to that of Clarke.* The remarks and illustrations, which I refer to, are to be found in his Inquiry into the Vulgar Notion of Nature, and in his Essay inquiring whether, and how, a Naturalist should consider Final Causes. Both of these tracts display powers which might have placed their author on a level with Descartes and Locke, had not his taste and inclination determined him more strongly to other pursuits. I am inclined to think, that neither of them is so well known as were to be wished. I do not even recollect to have seen it anywhere noticed, that some of the most striking and beautiful instances of design in the order of the material world, which occur in the Sermons preached at Boyle's Lecture, are borrowed from the works of the founder.f

To the English reader it is unnecessary to observe, that I allude to the Sermons preached at the Lecture founded by the Honorable Robert Boyle.

†Those instances, more especially, which are drawn from the anatomical structure of animals, and the adaptation of their perceptive organs to the habits of life for which they are destined.

next place, to those of our illustrious countrymen Newton and Clarke; the former of whom has exhibited in his Principia and Optics, the most perfect exemplifications which have yet appeared, of the cautious logic recommended by Bacon and Locke; while the other, in defending against the assaults of Leibnitz the metaphysical principles on which the Newtonian philosophy proceeds, has been led, at the same time, to vindicate the authority of various other truths, of still higher importance, and more general interest.

The chief subjects of dispute between Leibnitz and Clarke, so far as the principles of the Newtonian philosophy are concerned, have been long ago settled, to the entire satisfaction of the learned world. The monads, and the plenum, and the pre-established harmony of Leibnitz, already rank, in the public estimation, with the vortices of Descartes, and the plastic nature of Cudworth; while the theory of gravitation prevails every where over all opposition; and, as Mr. Smith remarks, "has advanced to the acquisition of the most universal empire that was ever established in philosophy." On these points, therefore, I have only to refer my readers to the collection published by Dr. Clarke, in 1717, of the controversial papers which passed between him and Leibnitz during the two preceding years; a correspondence equally curious and instructive; and which, it is to be lamented, that the death of Leibnitz in 1716 prevented from being longer continued.*

Notwithstanding, however, these great merits, he has written too little on such abstract subjects to entitle him to a place among English metaphysicians; nor has he, like Newton, started any leading thoughts which have since given a new direction to the studies of metaphysical inquirers. From the slight specimens he has left, there is reason to conclude, that his mind was still more happily turned than that of Newton, for the prosecution of that branch of science to which their contemporary Locke was then beginning to invite the attention of the public.

From a letter of Leibnitz to M. Remond de Montmort, it appears that he considered Newton, and not Clarke, as his real antagonist in this controversy. "M. Clarke, ou plutôt M. Newton, dont M. Clarke soutient les dogmes, est en dispute avec moi sur la philosophie." (Leib. Op. Tom. V. p. 33.) From another letter to the same correspondent we learn, that Leibnitz aimed at nothing less than the complete overthrow of the Newtonian philosophy; and that it was chiefly to his grand principle of the sufficient reason that he trusted for the accomplishment of this object. "J'ai reduit l'état de notre dispute à ce grand axiome, que rien n'existe, ou n'arrive sans qu'il y ait une raison suffisante, pourquoi il en est plutôt ainsi qu'autrement. S'il continue à me le nier, où en sera sa sincerité ? S'il me l'accorde, adieu le vuide, les atômes, et toute la philosophie de M. Newton." (Ibid.)

Although Newton does not appear to have devoted much of his time to Metaphysical researches, yet the general spirit of his physical investigations has had a great, though indirect influence on the metaphysical studies of his successors. It is justly and profoundly remarked by Mr. Hume, that "while Newton seemed to draw off the veil from some of the mysteries of nature, he showed, at the same time, the imperfections of the mechanical philosophy, and thereby restored her ultimate secrets to that obscurity in which they ever did, and ever will remain." In this way, his discoveries have cooperated powerfully with the reasonings of Locke in producing a general conviction of the inadequacy of our faculties to unriddle those sublime enigmas on which Descartes, Malebranche, and Leibnitz, had so recently wasted their strength, and which, in the ancient world, were regarded as the only fit objects of philosophical curiosity. It is chiefly too since the time of Newton, that the ontology and pneumatology of the dark ages have been abandoned for inquiries resting on the solid basis of experience and analogy; and that philosophers have felt themselves emboldened by his astonishing discoveries concerning the more distant parts of the material universe, to argue from the known to the unknown parts of the moral world. So completely has the prediction been verified which he himself hazarded, in the form of a query, at the end of his Optics, that "if natural philosophy should continue to be improved in its various branches, the bounds of moral philosophy would be enlarged also."

How far the peculiar cast of Newton's genius qualified him for prosecuting successfully the study of Mind, he has not afforded us sufficient data for judging; but such was the admiration with which his transcendent powers as a Mathematician and Natural Philosopher were universally regarded, that the slightest of his hints on the other subjects have been eagerly seized upon as indisputable axioms, though sometimes with little other evidence in their favor but the supposed sanction of his authority.*

See also a letter from Leibnitz to M. des Maizeaux in the same volume of his works, p. 39.

* Witness Hartley's Physiological Theory of the Mind, founded on a query in

The part of his works, however, which chiefly led me to connect his name with that of Clarke, is a passage in the Scholium annexed to his Principia,* which may be considered as the germ of the celebrated argument a priori for the existence of God, which is commonly, though I apprehend, not justly, regarded as the most important of all Clarke's contributions to Metaphysical Philosophy. I shall quote the passage in Newton's own words, to the oracular conciseness of which no English version can do justice.

"Eternus est, et infinitus, omnipotens et omnisciens; id est, durat ab æterno in æternum, et adest ab infinito in infinitum. ... Non est æternitas et infinitas, sed æternus et infinitus; non est duratio et spatium, sed durat et adest. Durat semper et adest ubique, et existendo

Newton's Optics; and a long list of theories in Medicine, grafted on a hint thrown out in the same query, in the form of a modest conjecture.

* This scholium, it is to be observed, first appeared at the end of the second edition of the Principia, printed at Cambridge in 1713. The former edition, published at London in 1687, has no scholium annexed to it. From a passage, however, in a letter of Newton's to Dr. Bentley (dated 1692), it seems probable, that as far back, at least, as that period, he had thoughts of attempting a proof a priori of the existence of God. After some new illustrations, drawn from his own discoveries, of the common argument from final causes, he thus concludes: "There is yet another argument for a Deity, which I take to be a very strong one; but, till the principles on which it is grounded are better received, I think it more advisable to let it sleep." (Four Letters from Sir I. Newton, to Dr. Bentley, p. 11. London, Dodsley, 1756.) It appears from this passage, that Newton had no intention, like his predecessor Descartes, to supersede, by any new argument of his own for the existence of God, the common one drawn from the consideration of final causes; and, therefore, nothing could be more uncandid than the following sarcasm pointed by Pope at the laudable attempts of his two countrymen to add to the evidence of this conclusion, by deducing it from other principles:

"Let others creep by timid steps and slow,
On plain experience lay foundations low,

By common sense to common knowledge bred,
And last to Nature's cause through Nature led:
We nobly take the high priori-road,

And reason downwards till we doubt of God."

That Pope had Clarke in his eye when he wrote these lines, will not be doubted by those who recollect the various other occasions in which he has stepped out of his way, to vent an impotent spleen against this excellent person.

And again :

"Let Clarke live half his life the poor's support,
But let him live the other half at court."

"Even in an ornament its place remark;

Nor in an hermitage set Dr. Clarke :'

in which last couplet there is a manifest allusion to the bust of Clarke, placed in a hermitage by Queen Caroline, together with those of Newton, Boyle, Locke, and Wollaston. See some fine verses on these busts in a poem called the Grotto, by Matthew Green.

semper et ubique durationem et spatium constituit." * Proceeding on these principles, Dr. Clarke argued, that, as immensity and eternity (which force themselves irresistibly on our belief as necessary existences, or, in other words, as existences of which the annihilation is impossible) are not substances, but attributes, the immense and eternal Being, whose attributes they are, must exist of necessity also. The existence of God, therefore, according to Clarke, is a truth that follows with demonstrative evidence from those conceptions of space and time which are inseparable from the human mind. "These,"

says Dr. Reid, "are the speculations of men of superior genius; but whether they be as solid as they are sublime, or whether they be the wanderings of imagination in a region beyond the limits of the human understanding, I am at a loss to determine." After this candid acknowledgment from Dr. Reid, I need not be ashamed to confess my own doubts and difficulties on the same question.†

But although the argument, as stated by Clarke, does not carry complete satisfaction to my mind, I think it must be granted that there is something peculiarly wonderful and overwhelming in those conceptions of immensity and eternity, which it is not less impossible to banish from our thoughts, than the consciousness of our own existence. Nay, further, I think that these conceptions are very intimately connected with the fundamental principles of Natural Religion. For when once we have established, from the evidences of design everywhere manifested around us, the existence of an intelligent and powerful cause, we are unavoidably led to apply to this cause our conceptions of immensity and eternity, and to conceive Him as filling the infinite extent of both with his presence and with his power. Hence we associate with the idea

Thus translated by Dr. Clarke, "God is eternal and infinite, omnipotent and omniscient; that is, he endures from everlasting to everlasting, and is present from infinity to infinity. He is not eternity or infinity, but eternal and infinite. He is not duration or space, but he endures and is present. He endures always, and is present everywhere, and by existing always and everywhere, constitutes duration and space.' (See Clarke's Fourth Reply to Leibnitz.)

† An argument substantially the same with this for the existence of God, is hinted at very distinctly by Cudworth, Intellect. System, Chap. V. sect. 3, 4. Also by Dr. Henry More, Enchir. Metaph. Cap. viii. sect. 8. See Mosheim's Trans. of Cudworth, Tom. II. p. 356.