4. I conceive that the mind has not been fairly dealt with in this and other similar questions of the same sort. Matter alone seems to have the privilege of presenting difficulties, and contradictions at every turn; but the moment any thing of this kind is observed in the understanding, all the petulance of logicians is up in arms, and the mind is made the mark on which they vent all the modes and figures of their impertinence. Let us take an example from some of these self-evident matters of fact, which contain at least as many, and as great contradictions, as any in the most abstruse metaphysical doctrine, such as in extension, motion, and the curve of lines. Now as to the first of these, extension: if we suppose it to be made up of points, which are in themselves without extension, but by their combination produce it, we must suppose two unextended things, when joined together, to become extended, which is like supposing, that by adding together several nothings, we can arrive at something. On the other hand, if we suppose the ultimate parts of which extension is composed, to be themselves extended, we then attribute extension to that which is indivisible, or affirm a thing to consist of parts, and to have none, at the same time. The old argument against the possibility of motion is well known: it was said that the body moving must either be in the place where it was, or in that into which it was passing. Now, if it was in either of these, or in any one place, it must be at rest; and as it could not be in both at once, it followed that a body moving could exist no where, or that there was no such thing as motion in nature. Again, a curve line is described mathematically by a point moving, but always out of a strait line. Now, a strait line is the nearest between any two points. But that a body should move forward, and not move strait forward to the next point to which it is going, seems to imply no less an absurdity than the affirming that a thing never moves in the direction in which it is going, but always out of it; for, if it moves in the same direction, the smallest moment of time, this is not a curve, but a strait line; and if it does not continue to move in the same direction at all, it seems utterly inconceivable that it should make any progress, or move either in a curve or a strait line. Yet any one who, on the strength of the contradiction involved in the ideas of extension, motion, or curve lines, should severally deny or disbelieve any one of them, would be thought to want common sense. I think there are certain facts of the mind which are equally evident and unaccountable. Those who contend that the one are to be admitted, and the other not, because the one are the objects of sense, and the other not, do not deserve any serious answer. It is as much a fact, that I remember having seen the sun yesterday, as that I see it to-day, and both of them are much more certain facts than