*

us. Thus heat, that is very agreeable to us in one degree, by a little greater increase of it proves no ordinary torment; and the most pleasant of all sensible objects, light itself, if there be too much of it, if increased beyond a due proportion to our eyes, causes a very painful sensation:* which is wisely Nay, in addition to being exceedingly painful, excess of light is destructive to our organs of vision; thus, by looking long and stedfastly at the sun, many Hindù penitents become totally blind. In my work on the Manners of the Hindus, I have given an account of the experiment of a novice in this hazardous branch of devotion, part of which I here extract: "Amongst useful exercises, he was ordered, he says, to look steadily at the sun, with his head elevated, and without winking. This experiment he was directed to repeat several times every day, until the organs of sight were inflamed to an extraordinary degree, accompanied by violent headaches. Sometimes he fancied he saw sparks, and sometimes globes of fire in the air. The Sannyasi, whose disciple he was, appeared highly delighted with his proficiency: he himself was blind with one eye, and the pupil, upon inquiry, found with dismay that he had lost it by the very experiment which he had imposed upon him. Fearing that his penance might end in total loss of sight, he left the oneeyed sage to enjoy his contemplations alone." (ii. 53.) Sir Isaac Newton, in a letter to Locke, published some years ago by Lord King, gives an extremely interesting account of certain experiments on light, made by himself, which nearly cost him his eyes. The reader, I am sure, who takes any interest in philosophy, will excuse the length of the extract:"The observation you mention with Boyle's book of colours, I once made upon myself, with the hazard of my eyes. The manner was this: I looked a very little while upon the sun in the looking-glass with my right eye, and then turned my eyes into a dark corner of my chamber, and winked, to observe the impression made, and the circles of colours which encompassed it, and how they decayed by degrees, and at last vanished. This I repeated a second and a third time. At the third time, when the phantasm of light and colours about it was almost vanished, intending my fancy upon them to see their last appearance, I found to my amazement that they began to return, and by little and little to become as lively and vivid as when I had newly looked upon the sun. But when I ceased to intend my fancy upon them, they vanished again. After this I found, that as often as I went into the dark and intended my mind upon them, as when a man looks earnestly to see anything which is difficult to be seen, I could make the phantasm return without looking any more upon the sun; and the oftener I made it return, the more easily I could make it return again. And at length, by only repeating this, without looking any more upon the sun, I made such an impression on my eyes, that if I looked upon the clouds, or a book, or any bright object, I saw upon it a round bright shape like the sun: and, which is still stranger, though I looked on the sun with my 'right eye only, and not with my left, yet my fancy began to make the impression upon my left eye as well as upon my right; for if I shut my right eye, and looked upon a book or the clouds with my left eye, Į

and favourably so ordered by nature, that when any object does by the vehemency of its operation, disorder the instruments of sensation, whose structures cannot but be very nice and delicate, we might by the pain be warned to withdraw before the organ be quite put out of order, and so be unfitted for its proper function for the future. The consideration of those objects that produc t may well persuade us that this is the end or use of pain; for though great light be insufferable to our eyes, yet the highest degree of darkness does not at all disease them, because that, causing no disorderly motion in it, leaves that curious organ unarmed in its natural state. But yet excess of cold as well as heat pains us, because it is equally destructive to that temper which is necessary to the preservation of life, and the exercise of the several functions of the body, and which consists in a moderate degree of warmth, or, if you please, a motion of the insensible parts of our bodies, confined within certain bounds.

5. Beyond all this, we may find another reason why God hath scattered up and down several degrees of pleasure and pain in all the things that environ and affect us, and blended them together in almost all that our thoughts and senses have to do with; that we, finding imperfection, dissatisfaction, and want of complete happiness, in all the enjoyments which the creatures can afford us, might be led to seek it in the could see the spectrum of the sun almost as plain as with my right eye, if I did but intend my fancy a little while upon it: for at first, if I shut my right eye and looked with my left, the spectrum of the sun did not appear till I intended my fancy upon it; but by repeating, this appeared every time more easily: and now, in a few hours' time, I had brought my eyes to such a pass, that I could look upon no bright object with either eye but I saw the sun before me, so that I durst neither write nor read; but to recover the use of my eyes, shut myself up in my chamber, made dark, for three days together, and used all means to divert my imagination from the sun; for if I thought upon him, I presently saw his picture, though I was in the dark. But by keeping in the dark, and employing my mind about other things, I began in three or four days to have some use of my eyes again, and by forbearing a few days longer to look upon bright objects, recovered them pretty well; though not so well but that, for some months after, the spectrum of the sun began to return as often as I began to meditate upon the phenomenon, even though I lay in bed in midnight, with my curtains drawn. But now I have been very well for many years, though I am apt to think, that if I durst venture my eyes, I could still make the phantasm return by the power of my fancy." (Life of Locke.)-ED.

enjoyment of Him, with whom there is fullness of joy, and at whose right hand are pleasures for evermore.

6. Pleasure and Pain. Though what I have here said may not, perhaps, make the ideas of pleasure and pain clearer to us than our own experience does, which is the only way that we are capable of having them, yet the consideration of the reason why they are annexed to so many other ideas, serving to give us due sentiments of the wisdom and goodness of the Sovereign Disposer of all things, may not be unsuitable to the main end of these inquiries, the knowledge and veneration of him being the chief end of all our thoughts, and the proper business of all understandings.

7. Existence and Unity.-Existence and Unity are two other ideas that are suggested to the understanding by every object without, and every idea within. When ideas are in our minds, we consider them as being actually there, as well as we consider things to be actually without us; which is, that they exist, or have existence: and whatever we can consider as one thing, whether a real being or idea, suggests to the understanding the idea of unity.

8. Power-Power also is another of those simple ideas which we receive from sensation and reflection: for, observing in ourselves that we can at pleasure move several parts of our bodies which were at rest; the effects, also, that natural bodies are able to produce in one another, occurring every moment to our senses, we both these ways get the idea of power.

9. Succession. Besides these there is another idea, which, though suggested by our senses, yet is more constantly offered to us by what passes in our minds; and that is the idea of succession. For if we look immediately into ourselves, and reflect on what is observable there, we shall find our ideas always, whilst we are awake or have any thought, passing in train, one going and another coming, without intermission.

10. Simple Ideas the Materials of all our Knowledge.These, if they are not all, are at least (as I think) the most considerable of those simple ideas which the mind has, and out of which is made all its other knowledge; all which it receives only by the two forementioned ways of sensation and reflection.

Nor let any one think these too narrow bounds for the capacious mind of man to expatiate in, which takes its flight further than the stars, and cannot be confined by the limits of the world; that extends its thoughts often even beyond the utmost expansion of matter, and makes excursions into that incomprehensible inane.* I grant all this, but desire any one to assign any simple idea which is not received from one of those inlets before mentioned, or any complex idea not made out of those simple ones. Nor will it be so strange to think these few simple ideas sufficient to employ the quickest thought or largest capacity, and to furnish the materials of all that various knowledge, and more various fancies and opinions of all mankind, if we consider how many words may be made out of the various composition of twenty-four letters; or if, going one step further, we will but reflect on the variety of combinations that may be made with barely one of the above-mentioned ideas, viz., number, whose stock is inexhaustible and truly infinite: and what a large and immense field doth extension alone afford the mathematicians!

CHAPTER VIII.

SOME FURTHER CONSIDERATIONS CONCERNING OUR SIMPLE IDEAS

1. Positive Ideas from privative Causes.-CONCERNING the simple ideas of sensation, it is to be considered, that whatsoever is so constituted in nature as to be able, by affecting our senses, to cause any perception in the mind, doth thereby produce in the understanding a simple idea, which, whatever be the external cause of it, when it comes to be taken notice of by our discerning faculty, it is by the mind looked on and

* "Beyond the visible diurnal sphere

Into the heaven of heavens I have presumed,
An earthly guest, and drawn empyreal air,

Thy lending."-MILTON.

"Extra flammantia monia mundi."-LUCRETIUS.

ED.

considered there to be a real positive idea in the understanding as much as any other whatsoever, though, perhaps, the cause of it be but a privation of the subject.

2. Thus the ideas of heat and cold, light and darkness, white and black, motion and rest, are equally clear and positive ideas in the mind; though, perhaps, some of the causes which produce them are barely privations in subjects from whence our senses derive those ideas. These the understanding, in its view of them, considers all as distinct positive ideas, without taking notice of the causes that produce them, which is an inquiry not belonging to the idea, as it is in the understanding, but to the nature of the things existing without us. These are two very different things, and carefully to be distinguished, it being one thing to perceive and know the idea of white or black, and quite another to examine what kind of particles they must be, and how ranged in the superficies, to make any object appear white or black.

3. A painter or dyer who never inquired into their causes, hath the ideas of white and black, and other colours, as clearly, perfectly, and distinctly in his understanding, and perhaps more distinctly, than the philosopher, who hath busied himself in considering their natures, and thinks he knows how far either of them is in its cause positive or privative; and the idea of black is no less positive in his mind than that of white, however the cause of that colour in the external object may be only a privation.

4. If it were the design of my present undertaking to inquire into the natural causes and manner of perception, I should offer this as a reason why a privative cause might, in some cases at least, produce a positive idea; viz., that all sensation being produced in us only by different degrees and modes of motion in our animal spirits, variously agitated by external objects, the abatement of any former motion must as necessarily produce a new sensation as the variation or increase of it, and so introduce a new idea, which depends only on a different motion of the animal spirits in that organ.

*

* See Buhle's Histoire de la Philosophie Moderne. The hypothesis which assumes the existence of a subtle fluid in the nerves, propagated by their means from the brain to the different parts of the body, is of VOL. I.

R