2. To suppose bodies organised or unorganised, to be made up of indivisible monads which have no parts, is contrary to all that we know of body. It is essential to a body to have parts; and every part of a body is a body, and has parts also. No number of parts, without extension or figure, not even an infinite number, if we may use that expression, can, by being put together, make a whole that has extension and figure, which all bodies have.

3. It is contrary to all that we know of bodies, to ascribe to the monads, of which they are supposed to be compounded, perception and active force. If a philosopher thinks proper to say that a clod of earth both perceives and has active force, let him bring his proofs. But he ought not to expect, that mén who have understanding will so far give it up as to receive without proof whatever his imagination may suggest.

4. This system overturns all authority of our senses, and leaves not the least ground to believe the existence of the objects of sense, or the existence of anything which depends upon the authority of our senses; for our perception of objects, according to this system, has no dependance upon anything external, and would be the same as it is, supposing external objects had never existed, or that they were from this moment annihilated.

It is remarkable that Leibnitz's system, that of Malebranche, and the common system of ideas, or images of external objects in the mind, do all agree in overturning all the authority of our senses; and this one thing, as long as men retain their senses, will always make all these systems truly ridiculous.

5. The last observation I shall make upon this system, which indeed is equally applicable to all the systems of perception I have mentioned, is, that it is all hypothesis, made up of conjectures and suppositions, without proof. The Peripatetics supposed sensible species to be sent forth by the objects of sense. The moderns suppose ideas in the brain or in the mind. Malebranche supposed that we perceive the ideas of the divine mind. Leibnitz supposed monads and a pre-established harmony; and these monads being creatures of his own making, he is at liberty to give them what properties and powers his fancy may suggest. In like manner, the Indian philosopher supposed that the earth is supported by a huge elephant, and that the elephant stands on the back of a huge tortoise.

Such suppositions, while there is no proof of them offered, are nothing but the fictions of human fancy; and we ought no more to believe them, than we believe Homer's fictions of Apollo's silver bow, or Minerva's shield, or Venus's girdle. Such fictions in poetry are agreeable to the rules of the art they are intended to please, not to convince. But the philosophers would have us to believe their fictions, though the account they give of the phenomena of nature has commonly no more probability than the account that Homer gives of the plague in the Grecian camp, from Apollo taking his station on a neighbouring mountain, and, from his silver bow, letting fly his swift arrows into the camp.

Men then only begin to have a true taste in philosophy when they have learned to hold hypotheses in just contempt; and to consider them as the reveries of speculative men, which will never have any similitude to the works of God.

The Supreme Being has given us some intelligence of his works by what our senses inform us of external things, and by what our consciousness and reflection inform us concerning the operations of our own minds. Whatever can be inferred from these common informations, by just and sound reasoning, is true and legitimate philosophy; but what we add to this from conjecture is all spurious and illegitimate.

After this long account of the theories advanced by philosophers to account for our perception of external objects, I hope it will appear, that neither Aristotle's theory of sensible species, nor Malebranche's of our seeing things in God, nor the common theory of our perceiving ideas in our own minds, nor Leibnitz's theory of monads and a pre-established harmony, give any satisfying account of this power of the mind, or make it more intelligible than it is without their aid. They are conjectures, and if they were true, would solve no difficulty, but raise many new ones. It is therefore more agreeable to good sense and to sound philosophy, to rest satisfied with what our consciousness and attentive reflection discover to us of the nature of perception, than by inventing hypotheses, to attempt to explain things which are above the reach of human understanding. I believe no man is able to explain how we perceive external objects, any more than how we are conscious of those that are internal, Perception, consciousness, memory, and imagination, are all original and simple powers of the mind, and parts of its constitution. For this reason, though I have endeavoured to show that the theories of philosophers on this subject are ill-grounded and insufficient, I do not attempt to substitute any other theory in their place.

Every man feels that perception gives him an invincible belief of the existence of that which he perceives; and that this belief is not the effect of reasoning, but the immediate consequence of perception. When philosophers have wearied themselves and their readers with their speculations upon this subject, they can neither strengthen this belief nor weaken it; nor can they show how it is produced. It puts the philosopher and the peasant upon a level; and neither of them can give any other reason for believing his senses, than that he finds it impossible for him to do otherwise.

CHAPTER XVI.

OF SENSATION.

HAVING finished what I intend, with regard to that act of mind which we call the perception of an external object, I proceed to consider another, which by our constitution is conjoined with perception, and not with perception only, but with many other acts of our minds; and that is sensation. To prevent repetition, I must refer the reader to the explication of this word given in Essay 1. chap. 1.

Almost all our perceptions have corresponding sensations which constantly accompany them, and, on that account, are very apt to be confounded with them. Neither ought we to expect that the sensation, and its corresponding perception, should be distinguished in common language, because the purposes of common life do not require it. Language is made to serve the purposes of ordinary conversation; and we have no reason to expect that it should make distinctions that are not of common use. Hence it happens that a quality perceived, and the sensation corresponding to that perception, often go under the same name.

This makes the names of most of our sensations ambiguous, and this ambiguity hath very much perplexed philosophers. It will be necessary to give some instances, to illustrate the distinction between our sensations and the objects of perception.

When I smell a rose, there is in this operation both sensation and perception. The agreeable odour I feel, considered by itself, without relation

to any external object, is merely a sensation. It affects the mind in a certain way; and this affection of the mind may be conceived, without a thought of the rose or any other object. This sensation can be nothing else than it is felt to be. Its very essence consists in being felt; and when it is not felt, it is not. There is no difference between the sensation and the feeling of it; they are one and the same thing. It is for this reason, that we before observed, that, in sensation, there is no object distinct from that act of the mind by which it is felt; and this holds true with regard to all

sensations.

Let us next attend to the perception which we have in smelling a rose. Perception has always an external object; and the object of my perception, in this case, is that quality in the rose which I discern by the sense of smell. Observing that the agreeable sensation is raised when the rose is near, and ceases when it is removed, I am led, by my nature, to conclude some quality to be in the rose which is the cause of this sensation. This quality in the rose is the object perceived; and that act of my mind, by which I have the conviction and belief of this quality, is what in this case I call perception.

But it is here to be observed, that the sensation I feel, and the quality in the rose which I perceive, are both called by the same name. The smell of a rose is the name given to both: so that this name hath two meanings; and the distinguishing its different meanings removes all perplexity, and enables us to give clear and distinct answers to questions about which philosophers have held much dispute.

Thus, if it is asked, Whether the smell be in the rose, or in the mind that feels it? The answer is obvious: That there are two different things signified by the smell of a rose ; one of which is in the mind, and can be in nothing but in a sentient being; the other is truly and properly in the rose. The sensation which I feel is in my mind. The mind is the sentient being; and as the rose is insentient, there can be no sensation, nor anything resembling sensation in it. But this sensation in my mind is occasioned by a certain quality in the rose which is called by the same name with the sensation, not on account of any similitude, but because of their constant concomitancy.

All the names we have for smells, tastes, sounds, and for the various degrees of heat and cold, have a like ambiguity; and what has been said of the smell of a rose may be applied to them. They signify both a sensation, and a quality perceived by means of that sensation. The first is the sign, the last the thing signified. As both are conjoined by nature, and as the purposes of common life do not require them to be disjoined in our thoughts, they are both expressed by the same name: and this ambiguity is to be found in all languages, because the reason of it extends to all. The same ambiguity is found in the names of such diseases as are indicated by a particular, painful sensation; such as the toothach, the headach. The toothach signifies a painful sensation, which can only be in a sentient being; but it signifies also a disorder in the body, which has no similitude to a sensation, but is naturally connected with it.

Pressing my hand with force against the table, I feel pain, and I feel the table to be hard. The pain is a sensation of the mind, and there is nothing that resembles it in the table. The hardness is in the table, nor is there anything resembling it in the mind. Feeling is applied to both, but in a different sense; being a word common to the act of sensation, and to that of perceiving by the sense of touch.

I touch the table gently with my hand, and I feel it to be smooth, hard,

and cold. These are qualities of the table perceived by touch; but I perceive them by means of a sensation which indicates them. This sensation not being painful, I commonly give no attention to it. It carries my thought immediately to the thing signified by it, and is itself forgot, as if it had never been. But by repeating it, and turning my attention to it, and abstracting my thought from the thing signified by it, I find it to be merely a sensation, and that it has no similitude to the hardness, smoothness, or coldness, of the table which are signified by it.

It is indeed difficult, at first, to disjoin things in our attention which have always been conjoined, and to make that an object of reflection which never was so before; but some pains and practice will overcome this difficulty in those who have got the habit of reflecting on the operations of their own minds.

Although the present subject leads us only to consider the sensations which we have by means of our external senses, yet it will serve to illustrate what has been said, and I apprehend is of importance in itself to observe, that many operations of mind, to which we give one name, and which we always consider as one thing, are complex in their nature, and made up of several more simple ingredients; and of these ingredients sensation very often makes one. Of this we shall give some instances.

The appetite of hunger includes an uneasy sensation and a desire of food. Sensation and desire are different acts of mind. The last, from its nature, must have an object; the first has no object. These two ingredients may always be separated in thought: perhaps they sometimes are in reality; but hunger includes both.

Benevolence towards our fellow-creatures includes an agreeable feeling; but it includes also a desire of the happiness of others. The ancients commonly called it desire: many moderns choose rather to call it a feeling. Both are right; and they only err who exclude either of the ingredients. Whether these two ingredients are necessarily connected, is perhaps difficult for us to determine, there being many necessary connexions which we do not perceive to be necessary; but we can disjoin them in thought. They are different acts of the mind.

An uneasy feeling, and a desire, are in like manner the ingredients of malevolent affections; such as malice, envy, revenge. The passion of fear includes an uneasy sensation or feeling, and an opinion of danger; and hope is made up of the contrary ingredients. When we hear of a heroic action, the sentiment which it raises in our mind is made up of various ingredients. There is in it an agreeable feeling, a benevolent affection to the person, and a judgment or opinion of his merit.

If we thus analyse the various operations of our minds, we shall find, that many of them which we consider as perfectly simple, because we have been accustomed to call them by one name, are compounded of more simple ingredients; and that sensation, or feeling, which is only a more refined kind of sensation, makes one ingredient, not only in the perception of external objects, but in most operations of the mind.

A small degree of reflection may satisfy us that the number and variety of our sensations and feelings is prodigious: for to omit all those which accompany our appetites, passions, and affections, our moral sentiments, and sentiments of taste, even our external senses furnish a great variety of sensations differing in kind, and almost in every kind an endless variety of degrees. Every variety we discern, with regard to taste, smell, sound, colour, heat, and cold, and in the tangible qualities of bodies, is indicated by a sensation corresponding to it.

The most general and the most important division of our sensations and feelings is into the agreeable, the disagreeable, and the indifferent. Every thing we call pleasure, happiness, or enjoyment, on the one hand; and on the other, every thing we call misery, pain, or uneasiness, is sensation or feeling: for no man can for the present be more happy, or more miserable than he feels himself to be. He cannot be deceived with regard to the enjoyment or suffering of the present moment.

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But I apprehend, that besides the sensations that are either agreeable, or disagreeable, there is still a greater number that are indifferent. these we give so little attention that they have no name, and are immediately forgot as if they had never been; and it requires attention to the operations of our minds to be convinced of their existence.

For this end we may observe, that to a good ear every human voice is distinguishable from all others. Some voices are pleasant, some disagreeable; but the far greater part can neither be said to be one or the other. The same thing may be said of other sounds, and no less of tastes, smells, and colours; and if we consider that our senses are in continual exercise while we are awake, that some sensation attends every object they present to us, and that familiar objects seldom raise any emotion pleasant or painful; we shall see reason, besides the agreeable and disagreeable, to admit a third class of sensations, that may be called indifferent.

The sensations that are indifferent, are far from being useless. Th serve as signs to distinguish things that differ; and the information have concerning things external, comes by their means. Thus, if a

had no ear to receive pleasure from the harmony or melody of sou would still find the sense of hearing of great utility: though sou him neither pleasure nor pain of themselves, they would give him much useful information; and the like may be said of the sensations we have by all the other senses.

As to the sensations and feelings that are agreeable or disagreeable, they differ much, not only in degree, but in kind and in dignity. Some belong to the animal part of our nature, and are common to us with the brutes: others belong to the rational and moral part. The first are more properly called sensations, the last feelings. The French word sentiment is common to both.

The intention of nature in them is for the most part obvious, and well deserving our notice. It has been beautifully illustrated by a very elegant French writer, in his Théorie des sentimens agréables.

The Author of Nature, in the distribution of agreeable and painful feelings, hath wisely and benevolently consulted the good of the human species, and hath even shown us, by the same means, what tenor of conduct we ought to hold. For, first, The painful sensations of the animal kind are admonitions to avoid what would hurt us; and the agreeable sensations of this kind, invite us to those actions that are necessary to the preservation of the individual, or of the kind. Secondly, By the same means nature invites us to moderate bodily exercise, and admonishes us to avoid idleness and inactivity on the one hand, and excessive labour and fatigue on the other. Thirdly, The moderate exercise of all our rational powers gives pleasure. Fourthly, Every species of beauty is beheld with pleasure, and every species of deformity with disgust; and we shall find all that we call beautiful, to be something estimable or useful in itself, or a sign of something that is estimable or useful. Fifthly, The benevolent affections are all accompanied with an agreeable feeling, the malevolent with the contrary. And, sixthly, The highest, the noblest, amd most durable plea