But these philosophers, instead of drawing a just inference from this observation, and concluding, that we have no idea of power or agency, separate from the mind, and belonging to causes; I say, instead of drawing this conclusion, they frequently search for the qualities, in which this agency consists, and are displeased with every system, which their reason suggests to them, in order to explain it. They have sufficient force of genius to free them from the vulgar error, that there is a natural and perceivable connexion betwixt the several sensible qualities and actions of matter; but not sufficient to keep them from ever seeking for this connexion in matter, or causes. Had they fallen upon the just conclusion, they would have returned back to the situation of the vulgar, and would have regarded all these disquisitions with indolence and indifference. At present they seem to be in a very lamentable condition, and such as the poets have given us but a faint notion of in their descriptions of the punishment of Sisyphus and Tantalus. For what can be imagined more tormenting, than to seek with eagerness, what for ever flies us; and seek for it in a place, where it is impossible it can ever exist?

But as nature seems to have observed a kind of justice and compensation in every thing, she has not neglected philosophers more than the rest of the creation; but has reserved them a consolation amid all their disappointments and afflictions. This consolation principally consists in their invention of the words: faculty and occult quality. For it being usual, after the frequent use of terms, which are really significant and intelligible, to omit the idea, which we would express by them, and to preserve only the custom, by which we recal the idea at pleasure; so it naturally happens, that after the frequent use of terms, which are wholly insignificant and unintelligible, we fancy them to be on the same footing with the precedent, and to have a secret meaning, which we might discover by reflection. The resemblance of their appearance deceives the mind, as is usual, and makes us imagine a thorough resemblance and conformity. By this means these philosophers set themselves at ease, and arrive at last, by an illusion, at the same indifference, which the people attain by their stupidity, and true philosophers by their moderate scepticism.

They need only say, that any phenomenon, which puzzles them, arises from a faculty or an occult quality, and there is an end of all dispute and enquiry upon the matter.

But among all the instances, wherein the Peripatetics have shewn they were guided by every trivial propensity of the imagination, no one is more-remarkable than their sympathies, antipathies, and horrors of a vacuum. There is a very remarkable inclination in human nature, to bestow on external objects the same emotions, which it observes in itself; and to find every where those ideas, which are most present to it. This inclination, it is true, is suppressed by a little reflection, and only takes place in children, poets, and the antient philosophers. It appears in children, by their desire of beating the stones, which hurt them: In poets, by their readiness to personify every thing: And in the antient philosophers, by these fictions of sympathy and antipathy. We must pardon children, because of their age; poets, because they profess to follow implicitly the suggestions of their fancy: But what excuse shall we find to justify our philosophers in so signal a weakness?

But here it may be objected, that the imagination, according to my own confession, being the ultimate judge of all systems of philosophy, I am unjust in blaming the antient philosophers for making use of that faculty, and allowing themselves to be entirely guided by it in their reasonings. In order to justify myself, I must distinguish in the imagination betwixt the principles which are permanent, irresistible, and universal; such as the customary transition from causes to effects, and from effects to causes: And the principles, which are changeable, weak, and irregular; such as those I have just now taken notice of. The former are the foundation of all our thoughts and actions, so that upon their removal human nature must immediately perish and go to ruin. The latter are neither unavoidable to mankind, nor necessary, or so much as useful in the conduct of life; but on the contrary are observed only to take place in weak minds, and being opposite to the other principles of custom and reasoning, may easily be subverted by a due contrast and opposition. For this reason the former are received by philosophy, and the latter rejected.

One who concludes somebody to be near him, when he hears an articulate voice in the dark, reasons justly and naturally; though that conclusion be derived from nothing but custom, which infixes and inlivens the idea of a human creature, on account of his usual conjunction with the present impression. But one, who is tormented he knows not why, with the apprehension of spectres in the dark, may, perhaps, be said to reason, and to reason naturally too: But then it must be in the same sense, that a malady is said to be natural; as arising from natural causes, though it be contrary to health, the most agreeable and most natural situation of man.

The opinions of the antient philosophers, their fictions of substance and accident, and their reasonings concerning substantial forms and occult qualities, are like the spectres in the dark, and are derived from principles, which, however common, are neither universal nor unavoidable in human nature. The modern philosophy pretends to be entirely free from this defect, and to arise only from the solid, permanent, and consistent principles of the imagination. Upon what grounds this pretension is founded must now be the subject of our enquiry.

The fundamental principle of that philosophy is the opinion concerning colours, sounds, tastes, smells, heat and cold; which it asserts to be nothing but impressions in the mind, derived from the operation of external objects, and without any resemblance to the qualities of the objects. Upon examination, I find only one of the reasons commonly produced for this opinion to be satisfactory, viz. that derived from the variations of those impressions, even while the external object, to all appearance, continues the same. These variations depend upon several circumstances. Upon the different situations of our health: A man in a malady feels a disagreeable taste in meats, which before pleased him the most.

Upon the different complexions and constitutions of men That seems bitter to one, which is sweet to another. Upon the difference of their external situation and position: Colours reflected from the clouds change according to the distance of the clouds, and according to the angle they make with the eye and luminous body. Fire also communicates the sensation of pleasure at one distance, and that of pain at another. Instances of this kind are very numerous and frequent.

The conclusion drawn from them, is likewise as satisfactory as can possibly be imagined. It is certain, that when different impressions of the same sense arise from any object, every one of these impressions has not a resembling quality existent in the object. For as the same object cannot, at the same time, be endowed with different qualities of the same sense, and as the same quality cannot resemble impressions entirely different; it evidently follows, that many of our impressions have no external model or archetype. Now from like effects we presume like causes. Many of the impressions of colour, sound, &c.

are confest to be nothing but internal existences, and to arise from causes, which no ways resemble them. These impressions are in appearance nothing different from the other impressions of colour, sound, &c. We conclude, therefore, that they are, all of them, derived from a like origin.

This principle being once admitted, all the other doctrines of that philosophy seem to follow by an easy consequence. For upon the removal of sounds, colours, beat, cold, and other sensible qualities, from the rank of continued independent existences, we are reduced merely to what are called primary qualities, as the only real ones, of which we have any adequate notion. These primary qualities are extension and solidity, with their different mixtures and modifications; figure, motion, gravity, and cohesion. The generation, encrease, decay, and corruption of animals and vegetables, are nothing but changes of figure and motion; as also the operations of all bodies on each other; of fire, of light, water, air, earth, and of all the elements and powers of nature. One figure and motion produces another figure and motion; nor does there remain in the material universe any other principle, either active or passive, of which we can form the most distant idea.

I believe many objections might be made to this system But at present I shall confine myself to one, which is in my opinion very decisive. I assert, that instead of explaining the operations of external objects by its means, we utterly annihilate all these objects, and reduce ourselves to the opinions of the most extravagant scepticism concerning them. If colours, sounds, tastes, and smells be merely perceptions, nothing we can conceive is possest of a real, continued, and independent existence; not even motion, extension and solidity, which are the primary qualities chiefly insisted on.

To begin with the examination of motion; it is evident this is a quality altogether inconceivable alone, and without a reference to some other object. The idea of motion necessarily supposes that of a body moving. Now what is our idea of the moving body, without which motion is incomprehensible? It must resolve itself into the idea of extension or of solidity; and consequently the reality of motion depends upon that of these other qualities.

This opinion, which is universally acknowledged concerning motion, I have proved to be true with regard to extension; and have shewn that it is impossible to conceive extension, but as composed of parts, endowed with colour or solidity. The idea of extension is a compound idea; but as it is not compounded of an infinite number of parts or inferior ideas, it must at last resolve itself into such as are perfectly simple and indivisible. These simple and indivisible parts, not being ideas of extension, must be non entities, unless conceived as coloured or solid. Colour is excluded from any real existence. The reality, therefore, of our idea of extension depends upon the reality of that of solidity, nor can the former be just while the latter is chimerical.

Let us, then, lend our attention to the examination of the idea of solidity.

The idea of solidity is that of two objects, which being impelled by the utmost force, cannot penetrate each other; but still maintain a separate and distinct existence. Solidity, therefore, is perfectly incomprehensible alone, and without the conception of some bodies, which are solid, and maintain this separate and distinct existence. Now what idea have we of these bodies? The ideas of colours, sounds, and other secondary qualities are excluded. The idea of motion depends on that of extension, and the idea of extension on that of solidity.

It is impossible, therefore, that the idea of solidity can depend on either of them. For that would be to run in a circle, and make one idea depend on another, while at the same time the latter depends on the former. Our modern philosophy, therefore, leaves us no just nor satisfactory idea of solidity; nor consequently of matter.