John Locke

“ By the complex idea of extended, figured, coloured, and all other sensible qualities, which is all that we know of it, we are as far from the idea of the substance of body, as if we knew nothing at all : nor after all the acquaintance and familiarity which we imagine we have with matter, and the many qualities men assure themselves they perceive and know in bodies, will it perhaps upon examination be found, that they have any more or clearer primary ideas belonging to body, than they have belonging to immaterial spirit. ”

“ For whensoever we would proceed beyond these simple ideas we have from sensation and reflection, and dive further into the nature of things, we fall presently into darkness and obscurity, perplexedness and difficulties, and can discover nothing further but our own blindness and ignorance. But whichever of these complex ideas be clearest, that of body, or immaterial spirit, this is evident, that the simple ideas that make them up are no other than what we have received from sensation or reflection : and so is it of all our other ideas of substances, even of God himself. ”

“ Sensation convinces us that there are solid extended substances ; and reflection, that there are thinking ones : experience assures us of the existence of such beings, and that the one hath a power to move body by impulse, the other by thought ; this we cannot doubt of. Experience, I say, every moment furnishes us with the clear ideas both of the one and the other. But beyond these ideas, as received from their proper sources, our faculties will not reach. If we would inquire further into their nature, causes, and manner, we perceive not the nature of extension clearer than we do of thinking. ”

“ We can as little understand how the parts cohere in extension, as how our spirits perceive or move. I allow it is usual for most people to wonder how any one should find a difficulty in what they think they every day observe. Do we not see (will they be ready to say) the parts of bodies stick firmly together ? Is there anything more common ? And what doubt can there be made of it ? And the like, I say, concerning thinking and voluntary motion. Do we not every moment experiment it in ourselves, and therefore can it be doubted ? ”

“ The degrees or extent wherein we ascribe existence, power, wisdom, and all other perfections (which we can have any ideas of) to that sovereign Being, which we call God, being all boundless and infinite, we frame the best idea of him our minds are capable of : all which is done, I say, by enlarging those simple ideas we have taken from the operations of our own minds, by reflection ; or by our senses, from exterior things, to that vastness to which infinity can extend them. ”

“ For my soul, being a real being as well as my body, is certainly as capable of changing distance with any other body, or being, as body itself ; and so is capable of motion. And if a mathematician can consider a certain distance, or a change of that distance between two points, one may certainly conceive a distance, and a change of distance, between two spirits ; and so conceive their motion, their approach or removal, one from another. ”

“ For our idea of substance is equally obscure, or none at all, in both ; it is but a supposed I know not what, to support those ideas we call accidents. It is for want reflection that we are apt to think that our senses show us nothing but material things. Every act of sensation, when duly considered, gives us an equal view of both parts of nature, the corporeal and spiritual. For whilst I know, by seeing or hearing, &c., that there is some corporeal being without me, the object of that sensation, I do more certainly know, that there is some spiritual being within me that sees and hears. ”

“ So that, however we consider motion, and its communication, either from body or spirit, the idea which belongs to spirit is at least as clear as that which belongs to body. And if we consider the active power of moving, or, as I may call it, motivity, it is much clearer in spirit than body ; since two bodies, placed by one another at rest, will never afford us the idea of a power in the one to move the other, but by a borrowed motion : whereas the mind every day affords us ideas of an active power of moving of bodies ”

“ He that will examine his complex idea of gold, will find several of its ideas that make it up to be only powers ; as the power of being melted, but of not spending itself in the fire ; of being dissolved in aqua regia, are ideas as necessary to make up our complex idea of gold, as its colour and weight : which, if duly considered, are also nothing but different powers. ”

“ But, in truth, the pressure of any ambient fluid, how great soever, can be no intelligible cause of the cohesion of the solid parts of matter. For, though such a pressure may hinder the avulsion of two polished superficies, one from another, in a line perpendicular to them, as in the experiment of two polished marbles ; yet it can never in the least hinder the separation by a motion, in a line parallel to those surfaces. ”

“ Thinking and motivity the primary ideas peculiar to spirit. The ideas we have belonging and peculiar to spirit, are thinking, and will, or a power of putting body into motion by thought, and, which is consequent to it, liberty. For, as body cannot but communicate its motion by impulse to another body, which it meets with at rest, so the mind can put bodies into motion, or forbear to do so, as it pleases. The ideas of existence, duration, and mobility, are common to them both. ”

“ God be simple and uncompounded ; yet I think I may say we have no other idea of him, but a complex one of existence, knowledge, power, happiness, &c., infinite and eternal : which are all distinct ideas, and some of them, being relative, are again compounded of others : all which being, as has been shown, originally got from sensation and reflection, go to make up the idea or notion we have of God. ”

“ For, to speak truly, yellowness is not actually in gold, but is a power in gold to produce that idea in us by our eyes, when placed in a due light : and the heat, which we cannot leave out of our ideas of the sun, is no more really in the sun, than the white colour it introduces into wax. These are both equally powers in the sun, operating, by the motion and figure of its sensible parts, so on a man, as to make him have the idea of heat ”

“ An obscure and relative idea of substance in general being thus made we come to have the ideas of particular sorts of substances, by collecting such combinations of simple ideas as are, by experience and observation of men’s senses, taken notice of to exist together ; and are therefore supposed to flow from the particular internal constitution, or unknown essence of that substance. Thus we come to have the ideas of a man, horse, gold, water, &c. ”

“ Thus the idea which an Englishman signifies by the name swan, is white colour, long neck, red beak, black legs, and whole feet, and all these of a certain size, with a power of swimming in the water, and making a certain kind of noise, and perhaps, to a man who has long observed this kind of birds, some other properties : which all terminate in sensible simple ideas, all united in one common subject. ”

“ Proof of this. Every one finds in himself that his soul can think, will, and operate on his body in the place where that is, but cannot operate on a body, or in a place, an hundred miles distant from it. ”

“ And therefore experimenting and discovering in ourselves knowledge, and the power of voluntary motion, as certainly as we experiment, or discover in things without us, the cohesion and separation of solid parts, which is the extension and motion of bodies ; we have as much reason to be satisfied with our notion of immaterial spirit, as with our notion of body, and the existence of the one as well as the other. ”

“ For all those powers that we take cognizance of, terminating only in the alteration of some sensible qualities in those subjects on which they operate, and so making them exhibit to us new sensible ideas, therefore it is that I have reckoned these powers amongst the simple ideas which make the complex ones of the sort ? ”

“ So that if any one will examine himself concerning his notion of pure substance in general, he will find he has no other idea of it at all, but only a supposition of he knows not what support of such qualities which are capable of producing simple ideas in us ”

“ God in his own essence incognisable. For it is infinity, which, joined to our ideas of existence, power, knowledge, &c., makes that complex idea, whereby we represent to ourselves, the best we can, the Supreme Being. ”

“ Because the ambient fluid, having a full liberty to succeed in each point of space, deserted by a lateral motion, resists such a motion of bodies, so joined, no more than it would resist the motion of that body were it on all sides environed by that fluid, and touched no other body ; and therefore, if there were no other cause of cohesion, all parts of bodies must be easily separable by such a lateral sliding motion. For if the pressure of the aether be the adequate cause of cohesion, wherever that cause operates not, there can be no cohesion. ”

“ If our sense of hearing were but a thousand times quicker than it is, how would a perpetual noise distract us. And we should in the quietest retirement be less able to sleep or meditate than in the middle of a sea-fight. ”

“ I know that people whose thoughts are immersed in matter, and have so subjected their minds to their senses that they seldom reflect on anything beyond them, are apt to say, they cannot comprehend a thinking thing, which perhaps is true : but I affirm, when they consider it well, they can no more comprehend an extended thing. ”

“ Thirdly, the aptness we consider in any substance, to give or receive such alterations of primary qualities, as that the substance so altered should produce in us different ideas from what it did before ; these are called active and passive powers : all which powers, as far as we have any notice or notion of them, terminate only in sensible simple ideas. ”

“ That since we have some reason (if there be any credit to be given to the report of things that our philosophy cannot account for) to imagine, that Spirits can assume to themselves bodies of different bulk, figure, and conformation of parts – whether one great advantage some of them have over us may not lie in this, that they can so frame and shape to themselves organs of sensation or perception, as to suit them to their present design, and the circumstances of the object they would consider. ”

“ For though the pressure of the particles of air may account for the cohesion of several parts of matter that are grosser than the particles of air, and have pores less than the corpuscles of air, yet the weight or pressure of the air will not explain, nor can be a cause of the coherence of the particles of air themselves. ”

“ The increase of motion by impulse, which is observed or believed sometimes to happen, is yet harder to be understood. We have by daily experience clear evidence of motion produced both by impulse and by thought ”