to express it, because this carries fomething more of positive in it than impenetrability, which is nega tive, and is perhaps more a confequence of folidity, than folidity it felf. This feems to be the most effential property of body, and that whereby we conceive it to fill fpace: The idea of which is, that where we imagine any space taken up by a folid fubftance, we conceive it fo to poffefs it, that it excludes all other solid substances. This refistance is so great, that no force can furmount it. all the bodies in the world preffing a drop of water on all fides, will never be able to overcome the refiftance it makes to their approaching one another, till it be removed out of their way.

The idea of folidity is diftinguished from that of pure space, in as much as this latter is neither capable of refiftance, nor motion: 'tis diftinguifhed from hardness, in as much as hardness is a firm cohaefion of the folid parts of matter making up maffes of a fenfible bulk, fo that the whole doth not easily change its figure. Indeed, hard and soft, as commonly apprehended by us, are but relative to the constitutions of our bodies: that being called hard which will put us to pain fooner than change its figure, by the preffure of any part of our bodies; and that foft, which changes the fituation of its parts upon an eafie and unpainful touch.

This difficulty of changing fituation amongst

the parts gives no more folidity to the hardest body, than to the fofteft; nor is an adamant one jot more folid than water: he that shall fill a yielding foft body well with air or water, will quickly find its resistance. By this we may diftinguish the idea of the extenfion of body, from the idea of the extenfion of Space: that of body, is the cohaefion or continuity of folid, feparable, and movable parts; that of /pace, the continuity of unfolid, infeparable, and immovable parts. Upon the folidity of bodies depends their mutual impulse, refiftance, and protrusion. Of pure space and folidity there are several (among which I confess my felf one) who perfwade themselves they have clear and diftinct ideas: and that they can think on Space without any thing in it that refifts, or is protruded by body, as well as on fomething that fills Space, that can be protruded by the impulse of other bodies, or refift their motion; the idea of the distance between the oppofite parts of a concave furface, being equally clear without, as with the idea of any folid parts between. If any one ask what this folidity is, I fend him to his fenfes to inform him let him put a flint or foot-ball between his hands, and then endeavour to join them, and he will know.

S

CHAP V.

Of fimple Ideas of divers Senfes.

Ome ideas we get into the mind by more than one fenfe, as fpace, extenfion, figure, rest and motion. These are perceivable by the eyes and touch.

Some

CHAP. VI.

Of fimple Ideas of Reflection.

Ome are had from reflection, only: fuch are the ideas we have of the Operations of our minds of which the two principal are perception or thinking ; and volition or willing. The powers of producing thefe operations are call'd faculties, which are the understanding and will, the feveral modes of thinking, &c. belong to this head..

CHA P. VII.

Of Simple Ideas of Senfation and Reflection.

Here are fome fimple ideas convey'd into the mind by all the ways of fenfation and

reflection; fuch are pleasure, pain, power, existence,

unity, fucceffion. Pleasure or delight, pain or uneafinefs accompany almost every impression on our fonfes, and every action or thought of the mind. By pleasure or pain we mean whatever delights or molefts us, whether it arifes from the thoughts of our minds; or any thing operating on our bodies. Satisfaction, delight, pleasure, happiness and unea'finefs, trouble, torment, mifery, &c. are but different degrees, the one of pleasure, the other of pain.

The author of our beings having given us a power over feveral parts of our bodies to move or keep them at reft as we think fit; and alfo by their motion to move our felves and other contiguous bodies; having alfo given a power to our minds in several inftances, to chufe amongst its ideas which it will think on: to excite us to thefe actions of thinking and motion he has join'd to feveral thoughts and fenfations à perception of delight without this we fhould have no reason to prefer one thought or action to another, motion to rest. In which state, man however furnish'd with the faculties of understanding and will, would be a very idle unactive creature, and pass his time only in a lazy lethargick dream.

Pain has the fame efficacy to fet us on work that pleasure has; fince we are as ready to avoid that, as to pursue this. This is worth our confideration, that pain is often produc'd by the fame ab

jects and ideas that produce pleasure in us.

This their near conjunction gives us new occafion of admiring the wisdom and goodness of our Maker, who defigning the prefervation of our being, has annexed pain to the application of many things to our bodies, to warn us of the harm they will do us, and as advices to withdraw us from them. But he not defigning our preservation barely, but the prefervation of every part and organ in its perfection, hath in many cafes annex'd pain to those very ideas which delight us. Thus heat that is very agreeable to us in one degree, by a little greater increase of it, proves no ordinary torment: which is wifely order'd by nature, that when any object does by the vehemence ofits operation dif order the instruments of fenfation, whose structures cannot but be very delicate, we might by the pain be warn'd to withdraw before the organ be quite put out of order. That this is the end of pain, appears from this confideration; that tho' great light is infufferable to the eyes; yet the highest degree of darkness does not at all disease them: becaufe that caufes no diforderly motion in that curious organ the eye. But excess of cold as well as heat pains us; because it is equally destructive to the temper which is neceffary to the prefervation of life.

Another reason why God hath annex'd feveral degrees of pleasure and pain to all the things that