CHAPTER VI.

THE ARGUMENT CUMULATIVE.

WERE there no example in the world of contrivance except that of the eye, it would be alone fufficient to fupport the conclufion which we draw from it, as to the neceffity of an intelligent Creator. It could never be got rid of: because it could not be accounted for by any other fuppofition, which did not contradict all the principles we poffess of knowledge; the principles according to which, things do, as often as they can be brought to the test of experience, turn out to be true or falfe. Its coats and humours, constructed, as the lenfes of a telescope are constructed, for the refraction of rays of light to a point, which forms the proper action of the organ; the provision in its muscular tendons for turning its pupil to the object, fimilar to that which is given to the telescope by fcrews, and upon which power of direction in the eye, the exercise of its office as an optical inftrument depends; the further provifion for its defence,

VOL. I.

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for

for its conftant lubricity and moisture, which we fee in its focket and its lids, in its gland for the fecretion of the matter of tears, its outlet or communication with the nofe for carrying off the liquid after the eye is washed with it; these provifions compofe altogether an apparatus, a fyftem of parts, a preparation of means, fo manifest in their defign, fo exquifite in their contrivance, fo fuccessful in their iffue, fo precious and fo infinitely beneficial in their ufe, as, in my opinion, to bear down all doubt that can be raised upon the fubject. And what I wish, under the title of the prefent chapter, to observe, is, that, if other parts of nature were inacceffible to our enquiries, or even if other parts of nature prefented nothing to our examination but diforder and confufion, the validity of this example would remain the fame. If there were but one watch in the world, it would not be less certain that it had a maker. If we had never in our lives feen any but one fingle kind of hydraulic machine; yet, if of that one kind we understood the mechanism and ufe, we should be as perfectly affured that it proceeded from the hand, and thought, and fkill of a workman, as if we visited a mufcum

of

of the arts, and faw collected there twenty different kinds of machines for drawing water, or a thousand different kinds for other purposes. Of this point each machine is a proof, independently of all the reft. So it is with the evidences of a divine agency. The proof is not a conclufion, which lies at the end of a chain of reasoning, of which chain each inftance of contrivance is only a link, and of which, if one link fail, the whole falls; but it is an argument feparately supplied by every feparate example. An error in ftating an example affects only that example. The argument is cumulative in the fulleft fense of that term. The eye proves it without the ear; the ear without the eye. The proof in each example is complete; for when the design of the part, and the conduciveness of its ftructure to that defign, is fhewn, the mind may fet itself at reft: no future confideration can detract any thing from the force of the example.

CHAPTER VII.

OF THE MECHANICAL AND IMMECHANICAL PARTS AND FUNCTIONS OF ANIMALS AND VEGETABLES.

Ir is not that every part of an animal or vegetable has not proceeded from a contriving mind; or that every part is not conftructed with a view to its proper end and purpose, according to the laws belonging to, and governing, the substance or the action made use of in that part; or that each part is not fo conftructed, as to effectuate its purpose whilst it operates according to thefe laws: but it is, becaufe these laws themfelves are not in all cafes equally understood; or, what amounts to nearly the fame thing, are not equally exemplified in more fimple proceffes, and more fimple machines;. that we lay down the distinction, here propofed, between the mechanical parts, and other parts, of animals and vegetables.

For inftance; the principle of mufcular motion, viz. upon what cause the swelling of the belly of the mufcle, and confequent

contraction

contraction of its tendons, either by an act of the will or by involuntary irritation, depends, is wholly unknown to us. The fubftance employed, whether it be fluid, gaseous, elastic, electrical, or none of thefe, or nothing refembling these, is alfo unknown to us: of course the laws belonging to that substance, and which regulate its action, are unknown to us. We fee nothing fimilar to this contraction in any machine which we can make, or any process which we can execute. So far (it is confeffed) we are in ignorance: but no further. This power and principle, from whatever cause it proceeds, being affumed, the collocation of the fibres to receive the principle, the difpofition of the muscles for the use and application of the power, is mechanical; and is as intelligible as the adjustment of the wires. and ftrings by which a puppet is moved. We fee therefore, as far as refpects the subject before us, what is not mechanical in the animal frame, and what is. The nervous influence (for we are often obliged to give names to things which we know little about)—I say the nervous influence, by which the belly or middle of the mufcle is fwelled, is not mechanical. The utility of the effect we perceive; G 3

the