tells us, that ideas of memory are diftinguifhed from those of imagination by the fuperior vivacity of the former *. This may fometimes, but cannot always, be true: for ideas of imagination are often mistaken for objects of fense; ideas of memory never. The former, therefore, must often be more lively than the latter; for, according to this author's own account, all ideas are weaker than impreffions, or informations of fenfe t. Dreaming perfons, lunatics, stage-players, enthusiasts, and all who are agitated by fear, or other violent paffions, are apt to mistake ideas of imagination for real things, and the perception of thofe ideas for real fenfation. And the fame thing is often experienced by perfons of strong fancy, and great fenfibility of temper, at a time when they are not troubled with any fits of irrationality or violent paffion.

ned imagination, The fimple apprehenfion of corporeal objects when absent. But cannot a good man imagine the remorfe of a murderer, or the anxities of a mifer? Cannot one invent new theories in the abstract philofophy, or even an entire new system of it? Imagination, in the modern philofophic language, feems to denote two things: 1. That power of the mind which contemplates ideas (that is, thoughts or notions) without referring them to real exiftence, or to our paft experience; 2. That power which combines ideas into new forms or affemblages.

* Treatife of Human Nature, vol. 1. p. 153

+ Ibid. p. 41.

L 2

But

But whatever difficulty we may find in defining or defcribing memory, fo as to diftinguish it from imagination, we are never at. any lofs about our own meaning, when we fpeak of remembering and of imagining. We all know what it is to remember, and what it is to imagine: a retrospect to former experience always attends the exertions of memory; but thofe of imagination are not attended with any fuch retrospect.

"" I re

"member to have feen a lion, and I can i

magine an elephant or centaur, which I "have never seen :" - Every body who uses these words knows very well what they mean, whether he be able to explain his meaning by other words or not. The truth is, that when we remember, we generally know that we remember; when we imagine, we generally know that we imagine*: fuch is our conftitution. We therefore do not fuppofe the evidence of memory uncertain, notwithstanding that we may be at a loss to explain the difference between that faculty and imagination: this difference is perfectly known to every man by experience, though perhaps no man can fully exprefs it in words. There are many things very familiar to us, which

*In dreams indeed this is not the cafe; but the delufions of dreaming, for all our frequent experience of them, are never fuppofed to affect in the leaft degree either the veracity of our faculties, or the certainty of our knowledge. See below, Part 2. chap. 2. fect. 2.

we

we have no words to exprefs. I cannot describe or define, either a red colour, which I know to be a fimple object, or a white colour, which I know to be a compofition of feven colours: but will any one hence infer, that I am ignorant of their difference, so as not to know, when I look on ermine, whether it be white or red? Let it not then be faid, that because we cannot define memory and imagination, therefore we are ignorant of their difference: every perfon of a found mind knows their difference, and can with certainty determine, when it is that he exerts the one, and when it is that he exerts the other.

I

SECT. V.

Of Reasoning from the Effect to the Cause.

Left chamber an hour my and now ago, at my return find a book on the table, the fize, and binding, and contents of which are fo remarkable, that I am certain it was not here when I went out; and that I never faw it before. I afk, who brought this book; and am told, that no body has entered my apartment fince I left it. That, fay I, is impoible. I make a more particular inquiry; and a fervant, in whofe veracity I can confide, affures me, that he has had his

eye on

my

my chamber-door the whole day, and that no perfon has entered it but myself only. Then, fay I, the perfon who brought this book must have come in by the window or the chimney; for it is impoffible that this book could have come hither of itself. The fervant bids me remember, that my chimney is too narrow to admit any human creature, and that the window is fecured on the infide in fuch a manner that it cannot be opened from without. I examine the walls; it is evident no breach has been made; and there is but one door to the apartment. What fhall I think? If the fervant's report be true, and if the book have not been brought by any visible agent, it must have come in a miraculous manner, by the interpofition of fome invifible caufe; for ftill I must repeat, that without fome caufe it could not possibly have come hither.

Let the reader confider the case, and deliberate with himself, whether I think irrationally on this occafion, or express myself too strongly, when I speak of the impoffibility of a book appearing in my chamber without fome cause of its appearance, either visible or invifible. I would not willingly refer such a phenomenon to a miracle; but still a miracle is poffible; whereas it is abfolutely impoffible that this could have happened without a caufe; at least it seems to me to be as real an impoffibility, as that a part should be greater than the whole, or that things e

qual

qual to one and the fame thing fhould be unequal to one another. And I prefume the reader will be of my opinion; for, in all my intercourfe with others, and after a careful examination of my own mind, I have never found any reason to think, that it is poffible for a human, or for a rational creature, to conceive a thing beginning to exist, and proceeding from no cause.

I pronounce it therefore to be an axiom, clear, certain, and undeniable, That "whatever beginneth to exift, proceedeth from "fome cause." I cannot bring myself to think, that the reverfe of any geometrical axiom is more incredible than the reverse of this; and therefore I am as certain of the truth of this, as I can be of the truth of the other; and cannot, without contradicting myself, and doing violence to my nature, even attempt to believe otherwise.

Whether this maxim be intuitive or demonftrable, may perhaps admit of fome difpute; but the determination of that point will not in the leaft affect the truth of the maxim. If it be demonftrable, we can then affign a reason for our belief of it: if it be intuitive, it is on the fame footing with other intuitive axioms; that is, we believe it, becaufe the law of our nature renders it impoffible for us to difbelieve it.

In proof of this maxim it has been faid, that nothing can produce itself. But this truth is not more evident than the truth to

be