by experience that the great defects of this faculty are neither to be cured, nor supplied by art. In what proportion soever it is given, it may be improved to some degree, no doubt, but memory will never present ideas to the human mind, as it does perhaps to superior intelligences, like objects in a mirror, where they may be viewed at every instant, all at once, without effort or toil, in their original freshness, and with their original precision, such as they were when they first came into the mind, or when they were first framed by it. Could memory serve us in this manner, our knowledge would be still very imperfect; but many errors into which we fall, and into which we are seduced, would be avoided, and the endless chicane of learned disputation would be stopped in a great measure. It is for this reason I have said so much of this faculty of the mind, as you will have occasion soon to observe.

The faculties, necessary for my purpose to be mentioned next, are those of compounding simple into complex ideas, and of comparing our ideas, which implies the just and nice discernment of them, in order to perceive the innumerable relations which they bear to one another. These are some of the steps by which the mind attempts to rise from particular to general knowledge. They have been called arts of the mind, but improperly, in some respects; for though the mind is forced to employ several arts, and to call in sense to the aid of intellect, even after it has full possession of its ideas, to help out its imperfect manner of knowing, and to lengthen a little its short tether; yet the composition, and comparison of ideas is plainly a lesson of nature: this lesson is taught us by the very first sensations we have. As the mind does not act till it is roused into action by external objects; so when it does act, it acts conformably to the suggestions it receives from these impressions, and takes with its first ideas the hints how to multiply, and improve them. If nature makes us lame, she gives crutches to lean upon. She helps us to walk where we cannot run, and to hobble where we cannot walk. She takes us by the hand, and leads us by experience to art.

Nature then has united in distinct substances, as we commonly speak, various combinations of those qualities, each of which causes in us the sensation it is appropriated to cause, and our organs are fitted to receive; so that several being thus combined, and making their impression together, may be said to cause a complex sensation. Thus we receive, among other ideas, those of soft and warm at the same instant, from the same piece of wax; or of hard and cold from the same piece of ice. Thus again; we receive the more complex ideas which substances still more composed, that is, substances wherein a greater variety of these qualities co-exists, are fitted to raise in us, such, for instance, VOL. III.-8

as the idea of a man, or a horse. As soon as we are born, various appearances present themselves to the sight, the din of the world strikes our ears, in short a multitude of impressions made on the tender organs of sense convey a multitude of ideas simple and complex, confusedly, and continually into the mind. The latter indeed, whether nature obtrudes them, or we make them, are composed of the former, and therefore we give very properly the first place to these in all discourses concerning ideas. But they have a priority of order rather than of existence; for the complex idea of the nurse comes into the mind as soon as the eyes of the child are opened, and is most probably the first idea received by the sight, though the simple idea produced by the taste of milk may have got into the mind a little sooner. Nor does the lesson of nature end here: she carries it on to all the different compositions of our simple ideas, and to all the different combinations we frame of our simple and complex ideas; from substances to mode, the dependencies, and affections of substances, and from them to the relations of things one to another; that is, she carries it on to all the operations of the mind, and to all the objects of our thoughts in the acquisition of knowledge.

If I meant by modes nothing but manners of being as some do, I should not ascribe our ideas of them to a further lesson of nature. She taught us this lesson, when she obtruded on us the complex ideas of substances. At least it seems so to me, who cannot comprehend the distinction of substances, and of mode or manner of being, as of two ideas that may be perceived separately, the one of a thing that subsists by itself, the other of a manner of being which cannot subsist by itself, but determines this thing to be what it is. I cannot consider a mode without referring it in my mind to something, of which it is or may be the mode: neither can I consider a substance otherwise than relatively to its modes, as something whereof I have no idea, and in which the modes, of which I have ideas, subsist. The complex idea we have, of every substance, is nothing more than a combination of several sensible ideas which determine the apparent nature of it to us. I say the apparent nature, and to us; for I cannot agree that these modes, such of them as fall under our observation, limit the real nature, or determine even the apparent nature to other beings. On the whole it will appear, whenever we consider this matter further, that the far greatest part of what has been said by philosophers about being, and substance, indeed all they have advanced beyond those clear and obvious notions which every thinking man frames, or may frame without their help, is pure jargon, or else something very trite, disguised under a metaphysical mask, and called by a hard name ontology, or ontosophy.

But to proceed, or rather to return; I understand by mode, in this place something else, something that carries our knowledge further than the complex ideas of substances. I understand in short what Mr. Locke understands by simple and mixed modes. The various combinations that our minds make of the same simple idea, and the various compositions that they make of simple ideas of different kinds. These ideas added to those of substances, and the whole stock completed by such as the mind acquires of the relation of its ideas, in comparing them as far as it is able to compare them, make up the entire system of human knowledge: and in the process of it from first to last, we are assisted directly or indirectly by the lessons of nature that have been, or that are to be mentioned.

Ideas of things computable, and measurable are the objects of mathematics. Ideas of moral, and immoral actions are the objects of ethics. From whence has the mathematician his first ideas of number, or his first ideas of solid extension, of lines, surfaces, and figures? From whence has the moralist his first ideas of happiness, and unhappiness, of good, and evil? The mind. can exercise a power, in some sort arbitrary, over all its simple ideas, that is, it can repeat them at its pleasure, and it can frame them into complex ideas, without any regard to actual, though with a regard to possible existence; which regard will be always preserved, unless the mind be disordered. The mind then has a power of framing all the different compositions, and combinations of ideas, about which these sciences are conversant; but yet these operations are not performed by the native energy of the mind alone, without any help, without any pattern. Nature lends the help, nature sets the pattern, when complex ideas of these modes and relations force themselves on the mind, as the complex ideas of substances do.

That every distinct object of external, and internal sense gives us the idea of an unit, or of one, is obvious to reflection: and I think it is no less obvious, that these objects suggest to the mind, nay oblige the mind to make various repetitions of this idea, and to frame all the simple modes of number by adding unit to unit. Thus for instance, we look up by day and we see one sun, by night and we see one moon. Plutarch's countryman, indeed, counted two moons; for he could not conceive that the moon he had left behind him in Boeotia, and that he saw at Athens, were the same. But though we see but one sun, and one moon, we see many stars. We attempt to count them, that is, we assign marks, or sounds to signify how many times we repeat the idea of an unit, which each of them gives us separately; or else we form a confused idea of numberless repetitions of this idea, like the savages who lift up both hands, and extend their fingers to

show that they have seen ten suns on their journey, or hold out a handful of their hair when they want to signify a number of suns which they cannot signify otherwise; because they have neither sounds, nor marks for the greater collections of units.

As arithmetic is one, so is geometry another constituent part of mathematics, and the very name points out to us, not only the objects, but the original of this science. I do not believe, on the word of Herodotus, nor even of Strabo, that the Egyptians were the inventors of it. I believe this, almost as little, as I believe on the word of Josephus, that antediluvian astronomers had engraved their observations on two pillars which existed in his time. But this tradition, whereby the invention of geometry is ascribed to a nation more ancient than tradition itself, though it may be fabulous, communicates to us, like many others that are so, a true fact. The true fact, I think, is this; that as soon as men ceased to range the woods, and plains in common, like their fellow animals, if they ever did so; as soon as societies were formed, and in those societies a division of property was made; nature, that led them to assign, led them to ascertain possessions. They did both, most probably, at first by sight, and guess. They paced out these possessions afterwards in length, and breadth; and ideas of modes of space were framed like ideas of modes of number: an unit twelve times repeated makes a dozen, twenty times repeated it makes a score. The length of one of their feet was, to these first geometricians, like an unit to the first arithmeticians. So many feet, five, I think, according to Pliny, made a pace, and one hundred and five-and-twenty of these made a stated measure of distance that continued long in use; for the stadium consisted of one hundred and twenty-five paces, according to the same author. Thus measuring, the practical part of geometry, came into use: and when it had been applied to two dimensions, it was soon applied to all three. The use of it was great, not only in the first distribution of property, but in every alteration of it, and especially after such confusions of it, as the inundations of the Nile might cause annually in Egypt, or other devastations in that and in other countries.

Nature that urged men, by necessity, to invention, helped them to invent. The natural face of a country taught them to give it an artificial face, and their own first rude essays in laying out lands, and building habitations, led them to contemplate the properties of lines, surfaces, and solids; and, little by little, to form that science, the pride of the human intellect, which has served to so many great and good purposes, and the application of which is grown, or growing perhaps, into some abuse. Nature set the example, example begot imitation, imitation practice, practice introduced speculation, and speculation in its turn im

proved practice. I might easily run through other examples of the same kind, to show how the first principles of arts and sciences are derived from ideas furnished by the productions, and operations of nature, such as our senses represent them to us; nay, how instinct instructs reason, the instinct of other animals the reason of man. But this would be superfluous trouble in writing to you, who have touched this subject so well, where you introduce nature speaking to man, in the third of your ethic epistles.

I will only mention, as I proposed to do, the ideas, or notions, about which moral philosophy is conversant. I distinguish here, which I should have done perhaps sooner, and I think with good reason, between ideas, and notions; for it seems to me, that as we compound simple into complex ideas, so the compositions we make of simple, and complex ideas may be called, more properly, and with less confusion and ambiguity, notions. Simple ideas, simple modes, complex ideas, mixed modes, and relations of all these, as well as the relations of the relations, are frequently blended together voluntarily, as use invites, or judgment directs; and, thus blended, they may therefore seem to be original, and untaught. But yet certain it is, that such notions as these obtrude themselves on the mind, as naturally and as necessarily, though not so directly nor immediately, as the complex ideas of substances, or any other complex ideas. Let us observe this in an example. We see one man kill another: and the complex idea, signified by the word kill, is obtruded on our sense as much as the complex idea of the man killed, or of his killer. The mind retains this image, and joining to it various ideas of circumstances and relations, of causes and effects, of motives and consequences, all which ideas have been raised in our minds by experience and observation, such notions as we intend by the words murder, assassination, parricide, or fratricide, are framed.

Nature teaches us, by experience and observation, not only to extend our notions, but to distinguish them with greater precision, just as we learn to rectify simple ideas of sensation, and to control sense by sense, if I may say so. Mr. Locke observes, that we learn first the names of these complex ideas and notions from other men, and the signification of them afterwards. Which is true, and it is the most early, and most common method whereby we acquire them. But this makes no alteration in the case. Whether the impressions that excited these complex ideas, and gave the mind occasion and means to form these notions, were made on our minds, or on the minds of other men; and whether the names that signify them were given by us, or by others, it is plain that nature taught mankind to make them, directly when she obtruded them, and indirectly when we seemed to invent