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PHYSICS. other accidents: which original, or adventitious difpofition being invifible to us, at leaft whilft the patient lives, we are apt to afcribe the unexpected accidents of a crifis, if it prove falutary, to the wonderful providence of nature; and if it happen otherwife, to overlook them. Plentiful evacuations, procured by medicines, are a kind of artificial crifes. Some bodies, we fee, are fo conftituted, that tho' the peccant humour, wrought on by the medicine, ought, as the physician thinks, to be expell'd by stool, in the generality of thofe who take rhubarb or fena; yet the peculiar difpofition of the patient's ftomach will make that an emetic, which was intended for a cathartic. Nor does this conftitution of the ftomach equally regard all purging medicines: for the fame ftomach that will reject them in the form of a potion, will quietly retain them, in that of pills. Thus mercury, which tho', when duly prepared, is ufually given to procure falivation, efpecially to fucculent bodies; yet there are fome patients, wherein, instead of falivating, 'twill work violently downwards, like a purge, or make fome other unexpected evacuation. And I have seen a patient, who, tho' young and very fat, could not be brought to falivate, either by the gentler ways; by turbith-mineral, or other harsher medicines, tho' adminiftred by very skilful phyficians and chirurgeons.

And this peculiarity may be as well contracted, as native: for fome perfons, especially after furfeits, having been ruffly dealt with, or, at least, tired out with a medicine of this or that kind of form, will afterwards nauseate and vomit up the like, tho' in other bodies it be very far from emetic.

We fee, alfo, that fometimes fudorific medicines, inftead of procuring fweat, prove briskly diuretic, and fometimes either purging or vomitive.

From all this we may argue, that the qualities of the irritating matter, and much more the particular difpofition of the patient's body, may procure evacuations at unexpected places.

There are alfo inftances of periodical and critical evacuations, at very inconvenient, and unufual vents. Thus fome women are recorded to have had their menfes, fometimes at the eyes, fometimes at the navel, fometimes at the mouth, &c. of which there feems no caufe fo probable, as fome peculiar ftructure, whether native or adventitious, of the internal parts concern'd in that discharge: and of fuch unusual structures, anatomifts must have seen many, fince I myself have obferv'd more than one or two. Now if these uncommon ways of difpofing of the morbific matter, were always falutary to the patient, the argument grounded on them would have more weight: but tho' moft men take notice of this fort of crifes, only when they are lucky, yet an impartial obferver fhall often find, that ill-condition'd and hurtful ones, may be made by unusual and unexpected ways. And, in fome tranflations of the morbific matter to diftant and nobler parts, perhaps it will be as difficult to fhew, by what channels or known ways the matter pafs'd from one to another, as 'tis to determine, how it was conducted to the parts that moft happily vented it.

'Tis my fettled opinion, that divine prudence is, at least, often con- PHYSICS. cern'd, in a peculiar manner, about the actions of men, and the things that happen to them, or has a neceffary connexion with the one, the other, or both. And tho' I think it probable, that in the conduct of that far greatest part of the univerfe, which is merely corporeal, the wife author of it feldom manifeftly procures a recefs from the fettled courfe of the univerfe, and especially from the moft general laws of motion; yet, where men, who are creatures, that he is pleas'd to endow with free-will (at leaft with regard to things not fpiritual) are nearly and highly concern'd; he may, not only fometimes by thofe fignal and manifeft interpofitions we call miracles, acted in a fupernatural way; but, as the fovereign lord and governor of the world, frequently give, by the intervention of rational minds, as well united, as not united to human bodies, feveral fuch determinations to the motion of parts in those bodies, and of others, which may be affected by them, as by laws merely mechanical, thofe parts of matter would not have had and by motions fo determin'd, either falutary or fatal crises, and many other things, conducive to the welfare or detriment of men, may be produced.

The interpofition of divine providence, in cafes of life and death, might be eafily fhewn to chriftians, from feveral paffages of fcripture. And, I think, it becomes a christian philofopher, to admit in general, that God fometimes in a peculiar, tho' fecret way, interpofes in the ordinary phe-nomena and events of crifes; but that this is done fo feldom, at least in a way that we can certainly difcern, that we are not haftily to have recourse to an extraordinary providence, and much less to the ftrange care and skill of that queftion'd Being call'd nature, in a particular cafe, if it may be probably accounted for by mechanical laws, and the ordinary course of things.

When we confider the world, and the phyfical changes that happen in it, with regard to the divine wifdom and providence; the arguments for the affirmative ought, in their kind, to have more force than thofe for the negative. For it feems more allowable, to argue a providence from the exquifite ftructure and symmetry of the mundane bodies, and the apt fubordination and train of caufes, than to infer from fome phyfical irregularities, that things are not fram'd and adminiftred by a wife author and governor. For the characters and impreffions of wifdom, confpicuous in the curious fabric, and orderly train of things, can, with no probability, be referr'd to blind chance, but to a moft intelligent and defigning agent. Whereas, on the other hand, the irregularities we fpeak of, are incomparably fewer than those things which are regular, and produc'd in an orderly way; and the divine maker of the univerfe being a moft free agent, and having an intellect infinitely fuperior to ours, may, in the production of feemingly irregular phenomena, have ends unknown to us, which even thefe irregularities may be very fit to compass.

SECT.

PHYSICS.

Axioms about nature, how far, and in

what fenfe to be admitted.

SECT. III.

T
O proceed, the most general and current axioms concerning nature,
employ'd in the writings of philofophers, may have a fair account
given of them, agreeably to the doctrine hitherto propos'd; tho' fome of
thefe axioms fuppofe, and others seem strongly to fupport the receiv'd no-
tion of nature.

But before I confider the particular maxims receiv'd concerning nature's actions, let us fee in what fenfe nature may, or may not, be faid to act at all, or to do this or that.

For ought I can clearly difcern, whatsoever is perform'd in the merely material world, is really done by particular bodies, acting according to the laws of motion, &c. fettled and maintain'd by God, among things corporeal. In which hypothefis, nature feems rather a notional thing, than a true phyfical, diftinct efficient; fuch as would be, in case Aristotle's doctrine were true, one of thofe intelligences he prefum'd to be the movers of the celestial orbs. But men often express themselves fo very ambiguously, or intricately, when they fay, that nature does this, or acts thus, that 'tis fcarce poffible intelligibly to tranflate their expreffions into any forms of fpeech, adequate to the originals.

1. In this axiom, every nature preferves itself; by the word nature, I fuppofe, is understood a natural body, otherwife I know not what it means. Thus, then, it may either fignify, that no one body tends to its own destruction, or that, in every body, there is a principle call'd nature, upon account whereof the body is vigilant and industrious to preserve its ftate, and to defend itself from the violence and attempts of all other bodies that oppofe, or endeavour to deftroy or harm it.

In the former fenfe, the axiom may be admitted, without any prejudice to our doctrine: according to which, inanimate bodies can have neither appetites, hatreds, nor defigns; fo that we may eafily grant, they have none to destroy themselves.

But, according to the other fenfe of the axiom, 'twill import, that every body has within itself a principle, whereby it defires, and with all its power endeavours to compafs its own prefervation; and both to do those things, that tend thereto, and oppofe all endeavours, that outward agents, or internal diftempers, may ufe to compafs the deftruction of it.

And, as this is the moft vulgar fenfe of the axiom, fo 'tis chiefly in this, that I am concern'd to examine it.

I conceive, then, that the moft wife creator of things at firft fo framed the world, and fettled fuch laws of motion between the bodies, which, as parts, compofe it; that by the affiftance of his general concourse, the portions of the univerfe, are lodg'd in fuch places, and furnifh'd with fuch powers, that, by the help of his general providence, they may have their beings continued and maintained, as long as the courfe he thought fit to establish amongst things corporeal, requires.

Upon this fuppofition, which is but reasonable, there will appear no PHYSICS. neceffity to have any recourse, for the preservation of particular bodies, to fuch an internal appetite and in-bred knowledge in each of them, as the naturists prefume: fince, by virtue of the original frame of things, and established laws of motion, bodies are neceffarily determined to act on fuch occafions, after the manner they would, if they had really an aim at felf-preservation.

Thus, 'tis all one to a lump of dough, whether you make it into a round loaf, a long roll, or a flat cake: for in whatever figure the hands leave it, that it retains without having any appetite to return to the former. The mariner's needle, before it is excited, may have no particular propenfity to one part of the heavens more than another; but when it has been duly touch'd upon a load-ftone, the flower-de-luce will be determin'd to the north, and the oppofite extreme to the fouth. So that, if the lily be drawn afide, towards the eaft or the weft, as foon as the force that detain'd it, is remov'd, it will return to its former position, and never rest, till it regard the north. But, in fpite of this feeming affection of the lily to that point of the horizon, yet, if the needle be duly touch'd upon the contrary pole of a vigorous load-ftone, the lily will presently lofe its former inclination, and regard the south part of the heavens.

2. Another received axiom concerning nature, is, that she never fails of her end. This propofition is very ambiguous. However, if by nature we here understand the Being, that the school-men ftyle Natura naturans ; I allow that nature never miffeth its end. For the omnifcient and almighty author of things having once framed the world, and establish'd in it the laws of motion, which he conftantly maintains, there can no irregularity happen, especially among the greater mundane bodies, that he did not from the beginning forefee and permit. And tho', on fome special occafions, this inftituted order, either feemingly or really, has been violated; yet these things happening but rarely, and for weighty ends and purposes, by the peculiar intervention of the firft caufe, either guiding or over-ruling the propenfities and motions of fecondary agents; it cannot be faid, that God is fruftrated of his ends by thefe exorbitances, whereby he moft wifely and effectually accomplishes them. But, if by nature be meant fuch a fubordinate principle, as men ufually understand by that name, I doubt the axiom is in many cafes falfe: for tho' the material world is fo conftituted, that, for the most part, things are brought to pass by corporeal ' agents, as regularly, as if they defigned the effects they produce; yet there are several inftances wherein things happen quite otherwife.

Thus when a woman is pregnant, the aim of nature is, to produce a perfect human fœtus; yet we often fee, nature widely miffing her mark, instead of that, produces a monfter. Thus the fap, that nature raises with intent to feed the fruit of a white-thorn, for inftance, is by graffing brought to nourish a fruit of quite another kind. So, when the malfter makes barly to fprout, whence nature intends to produce ftalks and ears, 'tis perverted to a very different purpose.

3. Another

PHYSICS.

3. Another celebrated axiom concerning nature, is, that she always acts by the shortest ways. But this rule, as well as feveral others, requires to be explained and limited, before it be admitted. 'Tis true, the omnifcient author of the univerfe has fo framed it, that most of its parts act as regularly in order to the ends propofed, as if they did it with defign. But fince inanimate bodies have no knowledge, it cannot reasonably be fuppofed, that they moderate and vary their own actions, according to the exigency of particular circumftances, wherewith they muft of neceffity be unacquainted; it were therefore ftrange, if various occurrences did not determine them to act by other than the fhortest ways, that lead to particular ends, if thofe other ways be more agreeable to the general laws or customs established among things corporeal. This I prove by inftances taken from gravity itfelf, a quality perhaps very probably referr'd to an innate power and propenfion. For if a heavy body be let fall into the free air, "twill take its courfe directly towards the centre of the earth; and, if it meet with an inclining plane, which puts it out of its way, it will not lofe its tendency towards the centre, but run along that plane, by which means its tendency downwards is profecuted, tho' not, as before, in a perpendicular line, yet in the shortest way it is permitted to take. Thefe obvious phenomena, I confefs, agree very well with the vulgar axiom, and poffibly were the chief things that induced men to frame it. But now let us fuppofe, that a little sphere of marble or steel, after having long fallen thro' the air, lights upon a pavement of hard ftone, that lies horizontal; in this cafe, experience fhews, that the falling globe will rebound to a confiderable height, and falling down again, rebound again, and so for several times fucceffively, before it approaches as near as is permitted it, to the centre of heavy bodies. But if nature acted in all cafes by the shortest ways, this fphere ought not to rebound at all. And having taken a good fea compass, and fuffer'd the magnetic needle to reft north and fouth; if I held the proper pole of a good load-ftone at a convenient diftance, on the right or left hand of the lily, this would be drawn afide from the north point towards the east or weft, as I pleased; and then the load-ftone being quite remov'd, the lily of the needle would indeed return northward, tho' not stop in the magnetic meridian, but paffing on feveral degrees beyond it, 'twould thence return without ftopping at the meridian line; and fo, by its vibrations, defcribe many arches ftill fhorter and fhorter, till at length it came to fettle on it, and recover that pofition, which, if nature always acted by the most compendious ways, it fhould have rested at the first time it had regain'd it. The truth is, that, at least, inanimate bodies, acting without knowledge or defign of their own, cannot ftop or moderate their own actions, but muft neceffarily move as they are determined by the general laws of motion; according to which, in one cafe, the impetus, that a body acquires by falling, is more powerful to carry it on beyond the line of direction, than the action of the caufes of gravity is to ftop it, as foon as it comes to the nearest place they can give it to the centre of the earth. And fomething like this happens in levity, as well as

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