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and yet it is plain, that they are much grosser than the rays of light, which have a free passage through glass ; and grosser also than the magnetic effluvia, which pass freely through all bodies, when those that produce smell will not pass through the thin membranes of a bladder, and many of them scarce ordinary white paper.

There is a great variety of smells, though we have but a few names for them; sweet, stinking, sour, rank, and musty, are almost all the denominations we have for odours ; though the smell of a violet, and of musk, both called sweet, are as distinct as any two smells what



TASTE is the next sense to be considered.
The organ of taste is the tongue and palate.

Bodies that emit light, sounds, and smells, are seen, heard, and smelt at a distance; but bodies are not tasted, but by immediate application to the organ; for till our meat touch our tongues, or palates, we taste it not, how near soever it be.

It may be observed of tastes, that though there be a great variety of them, yet, as in smells, they have only some few general names; as sweet, bitter, sour, harsh, rank, and some few others.


The fifth and last of our senses is touch; a sense spread over the whole body, though it be most eminent, ly placed in the ends of the fingers.

By this sense the tangible qualities of bodies are discerned; as hard, soft, smooth, rough, dry, wet, clammy, and the like.

But the most considerable of the qualities, that are perceived by this sense, are heat and cold.

The due temperament of those two opposite qualities, is the great instrument of nature, that she makes use of in most, if not all, her productions.

Heat is a very brisk agitation of the insensible parts of the object, which produces in us that sensation, from whence we denominate the object hot; so what in our . sensation is heat, in the object is nothing but motion. This appears by the way whereby heat is produced; for we see that the rubbing of a brass nail upon a board will make it very hot, and the axle-trees of carts and coaches are often hot, and sometimes to a degree, that it sets them on fire, by the rubbing of the nave of the wheel

upon it.

On the other side, the utmost degree of cold is the cessation of that motion of the insensible particles, which to our touch is heat.

Bodies are denominated hot and cold in proportion to the present temperament of that part of our body to which they are applied ; so that feels hot to one, which seems cold to another; nay, the same body, felt by the two hands of the same man, may at the same time appear hot to the one, and cold to the other: because the motion of the insensible particles of it may be more brisk than that of the particles of the other.

Besides the objects before-mentioned, which are peculiar to each of our senses, as light, and colour of the sight; sound of hearing; odours of smelling ; savour's of tasting ; and tangible qualities of the touch; there are two others that are common to all the senses; and those are pleasure and pain, which they may receive by and with their peculiar objects. Thus, too much light offends the eye; some sounds delight, and others grate the ear; heat in a certain degree is very pleasant, which may be augmented to the greatest torment; and so the rest.

These five.senses are common to beasts with men; nay, in some of thein, some brutes exceed mankind. But men are endowed with other faculties, which far excel any thing that is to be found in the other animals in this our globe.

Memory also brutes may be supposed to have, as well as men.


Of the Understanding of Man.

The understanding of man does so surpass that of brutes, that some are of opinion brutes are mere machines, without any manner of perception at all. But letting this opinion alone, as ill-grounded, we will proceed to the consideration of human understanding, and the distinct operations thereof.

The lowest degree of it consists in perception, which we have before in part taken notice of, in our discourse of the senses. Concerning which it may be convenient farther to observe, that, to conceive a right notion of perception, we must consider the distinct objects of it, which are simple ideas; v. g. such as are those signified by these words, scarlet, blue, sweet, bitter, heat, cold, &c. from the other objects of our senses; to which we may add the internal operations of our minds, as the objects of our own reflection, such as are thinking, will

ing, &c.

Out of these simple ideas are made, by putting them together, several compounded or complex ideas; as those signified by the words pebble, marygold, horse.

The next thing the understanding doth in its progress to knowledge, is to abstract its ideas, by which abstraction they are made general.

A general idea is an idea in the mind, considered there as separated from time and place; and so capable to represent any particular being that is coriformable to it. Knowledge, which is the highest degree of the speculative faculties, consists in the perception of the truth of affirmative, or negative, propositions.

This perception is either immediate, or mediaté. Immediate perception of the agreement, or disagreement, of two ideas, is when, by comparing them together in our minds, we see, or, as it were, behold, their agreement, or disagreement. This therefore is called intuitive knowledge. Thus we see that red is not green; that the whole is bigger than a part; and that two and two are equal to four.

The truth of these, and the like propositions, we know by a bare simple intuition of the ideas themselves, without any more ado; and such propositions are called selfevident.

The mediate perception of the agreement, or disagreement, of two ideas, is when, by the intervention of one or more other ideas, their agreement, or disagreement, is shown. This is called demonstration, or rational knowledge. For instance : The inequality of the breadth of two windows, or two rivers, or any two bodies that cannot be put together, may be known by the intervention of the same measure, applied to them both; and so it is in our general ideas, whose agreement or disagreement may be often shown by the intervention of some other ideas, so as to produce demonstrative knowledge; where the ideas in question cannot be brought together, and immediately compared, so as to produce intuitive knowledge.

The understanding doth not know only certain truth; but also judges of probability, which consists in the likely agreement, or disagreement, of ideas.

The assenting to any proposition as probable is called opinion or belief.

We have hitherto considered the great and visible parts of the universe, and those great masses of matter, the stars, planets, and particularly this our earth, together with the inanimate parts, and animate inhabitants of it; it may be now fit to consider what these sensible bodies are made of, and that is of unconceivably small bodies, or atoms, out of whose various combinations bigger moleculæ are made: and so, by a greater and greater composition, bigger bodies; and out of these the whole material world is constituted.

By the figure, bulk, texture, and motion, of these small and insensible corpuscles, all the phænomena of bodies may be explained.







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