soul of man is in its proper sensory). Nothing can any more act, or be acted upon, where it is not present, than it can be where it is not. We are sure the soul cannot perceive what it is not present to, because nothing can act, or be acted upon, where it is not."

Mr. Locke expresses himself so upon this point, that, for the most part, one would imagine that he thought that the ideas, or images of things, which he believed to be the immediate objects of perception, are impressions upon the mind itself; yet in some passages he rather places them in the brain, and makes them to be perceived by the mind there present. "There are some ideas," says he, " which have admittance only through one sense; and if the organs or the nerves, which are the conduits to convey them from without to their audience in the brain, in the mind's presence-room, if I may so call it, are so disordered as not to perform their function, they have no postern to be admitted by.

"There seems to be a constant decay of all our ideas, even of those that are struck deepest. The pictures drawn in our minds are laid in fading colours. Whether the temper of the brain makes this difference, that in some it retains the characters, drawn on it like marble, in others like freestone, and in others little better than sand, I shall not inquire.”

From these passages of Mr. Locke, and others of a like nature, it is plain, that he thought that there are images of external objects conveyed to the brain. But whether he thought with Des Cartes and Newton, that the images in the brain are perceived by the mind there present, or that they are imprinted on the mind itself, is not so evident.

Now, with regard to this hypothesis, there are three things that deserve to be considered, because the hypothesis leans upon them; and, if any one of them fail, it must fall to the ground. The first is, That the soul has its seat, or, as Mr. Locke calls it, its presence-room, in the brain. The second, That there are images formed in the brain of all the objects of The third, That the mind or soul perceives these images in the brain; and that it perceives not external objects immediately, but only perceives them by means of those images.

sense.

As to the first point, That the soul has its seat in the brain, this, surely, is not so well established, as that we can safely build other principles upon it. There have been various opinions and much disputation about the place of spirits; whether they have a place? and if they have, how they occupy that place? After men had fought in the dark about these points for ages, the wiser part seem to have left off disputing about them, as matters beyond the reach of the human faculties.

As to the second point, That images of all the objects of sense are formed in the brain, we may venture to affirm, that there is no proof nor probability of this, with regard to any of the objects of sense; and that with regard to the greater part of them, it is words without any meaning.

eye,

We have not the least evidence that the image of any external object is formed in the brain. The brain has been dissected times innumerable by the nicest anatomists; every part of it examined by the naked and with the help of microscopes; but no vestige of an image of any external object was ever found. The brain seems to be the most improper substance that can be imagined for receiving or retaining images, being a soft moist medullary substance.

But how are these images formed? or whence do they come? Says Mr. Locke, the organs of sense and nerves convey them from without. This is just the Aristotelian hypothesis of sensible species, which modern philo

sophers have been at great pains to refute, and which must be acknowledged to be one of the most unintelligible parts of the Peripatetic system. Those who consider species of colour, figure, sound, and smell, coming from the object, and entering by the organs of sense, as a part of the scholastic jargon long ago discarded from sound philosophy, ought to have discarded images in the brain along with them. There never was a shadow of argument brought by any author, to show that an image of any external object ever entered by any of the organs of sense.

That external objects make some impression on the organs of sense, and by them on the nerves and brain, is granted; but that those impressions resemble the objects they are made by, so as that they may be called images of the objects, is most improbable. Every hypothesis that has been contrived shows that there can be no such resemblance; for neither the motions of animal spirits, nor the vibrations of elastic chords, or of elastic ether, or of the infinitesimal particles of the nerves, can be supposed to resemble the objects by which they are excited.

We know, that, in vision, an image of the visible object is formed in the bottom of the eye by the rays of light. But we know also, that this image cannot be conveyed to the brain, because the optic nerve, and all the parts that surround it, are opaque and impervious to the rays of light; and there is no other organ of sense in which any image of the object is formed.

It is farther to be observed, that, with regard to some objects of sense, we may understand what is meant by an image of them imprinted on the brain; but, with regard to most objects of sense, the phrase is absolutely unintelligible, and conveys no meaning at all. As to objects of sight, I understand what is meant by an image of their figure in the brain: But how shall we conceive an image of their colour where there is absolute darkness? And as to all other objects of sense, except figure and colour, I am unable to conceive what is meant by an image of them. Let any man say, what he means by an image of heat and cold, an image of hardness or softness, an image of sound, of smell, or taste. The word image, when applied to these objects of sense, has absolutely no meaning. Upon what a weak foundation, then, does this hypothesis stand, when it supposes, that images of all the objects of sense are imprinted on the brain, being conveyed thither by the conduits of the organs and nerves?

The third point in this hypothesis is, That the mind perceives the images in the brain, and external objects only by means of them. This is as improbable as that there are such images to be perceived. If our powers of perception be not altogether fallacious, the objects we perceive are not in our brain, but without us. We are so far from perceiving images in the brain, that we do not perceive our brain at all; nor would any man ever have known that he had a brain, if anatomy had not discovered, by dissection, that the brain is a constituent part of the human body.

To sum up what has been said with regard to the organs of perception, and the impressions made upon our nerves and brain. It is a law of our nature, established by the will of the Supreme Being, that we perceive no external object but by means of the organs given us for that purpose. But these organs do not perceive. The eye is the organ of sight, but sees not. A telescope is an artificial organ of sight. The eye is a natural organ of sight, but it sees as little as the telescope. We know how the eye forms a picture of the visible object upon the retina; but how this picture makes us see the object, we know not; and if experience had not formed us that such a picture is necessary to vision, we should never

have known it. We can give no reason why the picture on the retina should be followed by vision, while a like picture on any other part of the body produces nothing like vision.

It is likewise a law of our nature, that we perceive not external objects, unless certain impressions be made by the object upon the organ, and by means of the organ upon the nerves and brain. But of the nature of those impressions we are perfectly ignorant; and though they are conjoined with perception by the will of our Maker, yet it does not appear that they have any necessary connexion with it in their own nature, far less that they can be the proper efficient cause of it. We perceive, because God has given us the power of perceiving, and not because we have impressions from objects. We perceive nothing without those impressions, because our Maker has limited and circumscribed our powers of perception, by such laws of nature as to his wisdom seemed meet, and such as suited our rank in his creation.

CHAPTER V.

OF PERCEPTION.

IN speaking of the impressions made on our organs in perception, we build upon facts borrowed from anatomy and physiology, for which we have the testimony of our senses. But being now to speak of perception itself, which is solely an act of the mind, we must appeal to another authority. The operations of our minds are known not by sense, but by consciousness, the authority of which is as certain and as irresistible as that of sense.

In order, however, to our having a distinct notion of any of the operations of our own minds, it is not enough that we be conscious of them, for all men have this consciousness : It is farther necessary that we attend to them while they are exerted, and reflect upon them with care, while they are recent and fresh in our memory. It is necessary that by employing ourselves frequently in this way, we get the habit of this attention and reflection; and therefore, for the proof of facts which I shall have occasion to mention upon this subject, I can only appeal to the reader's own thoughts, whether such facts are not agreeable to what he is conscious of in his own mind.

If therefore, we attend to that act of our mind which we call the perception of an external object of sense, we shall find in it these three things. First, Some conception or notion of the object perceived. Secondly, A strong and irresistible conviction and belief of its present existence. And, Thirdly, That this conviction and belief are immediate, and not the effect of reasoning.

First, It is impossible to perceive an object without having some notion or conception of that which we perceive. We may indeed conceive an object which we do not perceive; but when we perceive the object, we must have some conception of it at the same time; and we have commonly a more clear and steady notion of the object while we perceive it, than we have from memory or imagination when it is not perceived. Yet, even in perception, the notion which our senses give of the object may be more or less clear, more or less distinct, in all possible degrees.

Thus we see more distinctly an object at a small than at a great distance. An object at a great distance is seen more distinctly in a clear than in a

foggy day. An object seen indistinctly with the naked eye, on account of its smallness, may be seen distinctly with a microscope. The objects in this room will be seen by a person in the room less and less distinctly as the light of the day fails; they pass through all the various degrees of distinctness according to the degrees of the light, and at last, in total darkness, they are not seen at all. What has been said of the objects of sight is so easily applied to the objects of the other senses, that the application may be left to the reader.

In a matter so obvious to every person capable of reflection, it is necessary only farther to observe, that the notion which we get of an object, merely by our external sense, ought not to be confounded with that more scientific notion which a man, come to the years of understanding, may have of the same object, by attending to its various attributes, or to its various parts, and their relation to each other, and to the whole. Thus the notion which a child has of a jack for roasting meat, will be acknowledged to be very different from that of a man who understands its construction, and perceives the relation of the parts to one another, and to the whole. The child sees the jack and every part of it as well as the man: the child, therefore, has all the notion of it which sight gives; whatever there is more in the notion which the man forms of it, must be derived from other powers of the mind, which may afterwards be explained. This observation is made here only, that we may not confound the operations of different powers of the mind, which, by being always conjoined after we grow up to understanding, are apt to pass for one and the same.

Secondly, In perception we not only have a notion more or less distinct of the object perceived, but also an irresistible conviction and belief of its existence. This is always the case when we are certain that we perceive it. There may be a perception so faint and indistinct, as to leave us in doubt whether we perceive the object or not. Thus, when a star begins to twinkle as the light of the sun withdraws, one may, for a short time, think he sees it, without being certain, until the perception acquires some strength and steadiness. When a ship just begins to appear in the utmost verge of the horizon, we may at first be dubious whether we perceive it or not but when the perception is in any degree clear and steady, there remains no doubt of its reality; and when the reality of the perception is ascertained, the existence of the object perceived can no longer be doubted.

By the laws of all nations, in the most solemn judicial trials wherein men's fortunes and lives are at stake, the sentence passes according to the testimony of eye or ear witnesses of good credit. An upright judge will give a fair hearing to every objection that can be made to the integrity of a witness, and allow it to be possible that he may be corrupted; but no judge will ever suppose that witnesses may be imposed upon by trusting to their eyes and ears: And if a sceptical counsel should plead against the testimony of the witnesses, that they had no other evidence for what they declared but the testimony of their eyes and ears, and that we ought not to put so much faith in our senses, as to deprive men of life or fortune upon their testimony; surely no upright judge would admit a plea of this kind. I believe no counsel, however sceptical, ever dared to offer such an argument; and if it was offered, it would be rejected with disdain.

Can any stronger proof be given, that it is the universal judgment of mankind that the evidence of sense is a kind of evidence which we may securely rest upon in the most momentous concerns of mankind; that it is a kind of evidence against which we ought not to admit any reasoning;

and therefore, that to reason either for or against it, is an insult to common sense?

The whole conduct of mankind, in the daily occurrences of life, as well as the solemn procedure of judicatories in the trial of causes, civil and criminal, demonstrates this. I know only of two exceptions that may be offered against this being the universal belief of mankind.

The first exception is that of some lunatics, who have been persuaded of things that seem to contradict the clear testimony of their senses. It is said there have been lunatics and hypochondriacal persons who seriously believed themselves to be made of glass; and in consequence of this lived in continual terror of having their brittle frame shivered into pieces.

All I have to say to this is, that our minds in our present state are, as well as our bodies, liable to strange disorders; and as we do not judge of the natural constitution of the body, from the disorders or diseases to which it is subject from accidents, so neither ought we to judge of the natural powers of the mind from its disorders, but from its sound state. It is natural to man, and common to the species, to have two hands and two feet; yet I have seen a man, and a very ingenious one, who was born without hands or feet. It is natural to man to have faculties superior to those of brutes; yet we see some individuals whose faculties are not equal to those of many brutes; and the wisest man may, by various accidents, be reduced to this state. General rules that regard those whose intellects are sound, are not overthrown by instances of men whose intellects are hurt by any constitutional or accidental disorder.

The other exception that may be made to the principle we have laid down, is that of some philosophers who have maintained, that the testimony of sense is fallacious, and therefore ought never to be trusted. Perhaps it might be a sufficient answer to this to say, that there is nothing so absurd which some philosophers have not maintained. It is one thing to profess a doctrine of this kind, another seriously to believe it, and to be governed by it in the conduct of life. It is evident, that a man who did not believe his senses, could not keep out of harm's way an hour of his life; yet in all the history of philosophy, we never read of any sceptic that ever stepped into fire or water because he did not believe his senses, or that showed, in the conduct of life, less trust in his senses than other men have. This gives us just ground to apprehend, that philosophy was never able to conquer that natural belief which men have in their senses; and that all their subtile reasonings against this belief were never able to persuade themselves.

It appears, therefore, that the clear and distinct testimony of our senses carries irresistible conviction along with it, to every man in his right judgment.

I observed, thirdly, That this conviction is not only irresistible, but it is immediate; that is, it is not by a train of reasoning and argumentation that we come to be convinced of the existence of what we perceive; we ask no argument for the existence of the object, but that we perceive it; perception commands our belief upon its own authority, and disdains to rest its authority upon any reasoning whatsoever.

The conviction of a truth may be irresistible, and yet not immediate. Thus, my conviction that the three angles of every plain triangle, are equal to two right angles, is irresistible, but it is not immediate: I am convinced of it by demonstrative reasoning. There are other truths in mathematics of which we have not only an irresistible, but an immediate conviction. Such are the axioms. Our belief of the axioms in mathe