view no error be discovered, yet he is conscious that there may be errors, tho' they have escaped him. As to the other kind of demonftrative reasoning, founded on propofitions of which we are intuitively certain; I justly call it demonftrative, because it affords the fame conviction that arifes from mathematical reasoning. In both, the means of conviction are the fame, viz. a clear perception of the relation between two ideas: and there are many relations of which we have ideas no lefs clear than of equality; witness substance and quality, the whole and its parts, caufe and effect, and many others. From the intuitive propofition, for example, That nothing which begins to exist can exift without a caufe, I can conclude, that fome one being must have existed from all eternity, with no lefs certainty, than that the three angles of a triangle are equal to two right angles. What falls next in order, is that inferior fort of knowledge which is termed opinion; and which, like knowledge properly fo termed, is founded in fome inftances upon intuition, and in fome upon reafoning. But it differs from knowledge properly properly fo termed in the following particular, that it produces different degrees of conviction, fometimes approaching to certainty, fometimes finking toward the verge of improbability. The conftancy and uniformity of natural operations, is a fit subject for illuftrating that difference. The future fucceffive changes of day and night, of winter and fummer, and of other fucceffions which have hitherto been constant and uniform, fall under intuitive knowledge, because of these we have the highest conviction. As the conviction is inferior of fucceffions that hitherto have varied in. any degree, these fall under intuitive opinion. We expect fummer after winter with the utmost confidence; but we have not the fame confidence in expecting a hot fummer or a cold winter. And yet the probability approaches much nearer to certainty, than the intuitive opinion we have, that the operations of nature are extremely fimple, a propofition that is little rely'd on. As to opinion founded on reasoning, it is obvious, that the conviction produced by reafoning, can never rife above what is produced by the intuitive propofition VOL. III. D d upon upon which the reasoning is founded. And that it may be weaker, will appear from confidering, that even where the fundamental propofition is certain, it may lead to the conclusive opinion by intermediate propofitions, that are probable only, not certain. In a word, it holds in general with respect to every fort of reasoning, that the conclufive propofition can never rife higher in point of conviction, than the very lowest of the intuitive propofitions employ'd as steps in the reasoning. The perception we have of the contingency of future events, opens a wide field. to our reasoning about probabilities. That perception involves more or less doubt according to its fubject. In some instances, the event is perceived to be extremely doubtful; in others, it is perceived to be lefs doubtful. It appears altogether doubtful, in throwing a dye, which of the fix fides will turn up; and for that reason, we cannot justly conclude for one rather than for another. If one only of the fix fides be marked with a figure, we conclude, that a blank will turn up; and five to one is an equal wager that fuch will be the effect. In judging of the future behaviour of a man man who has hitherto been governed by interest, we may conclude with a probability approaching to certainty, that interest will continue to prevail. Belief comes laft in order, which, as defined above, is knowledge of the truth of facts that falls below certainty, and involves in its nature fome degree of doubt. It is alfo of two kinds; one founded upon intuition, and one upon reafoning. Thus, knowledge, opinion, belief, are all of them equally distinguishable into intuitive and difcurfive. Of intuitive belief, I discover three different fources or caufes. First, A present object. Second, An object formerly present. Third, The testimony of others. To have a clear conception of the first cause, it must be observed, that among the fimple perceptions that compose the complex perception of a prefent object, a perception of real and present existence is one. This perception rifes commonly to certainty; in which cafe it is a branch of knowledge properly fo termed; and is handled as fuch above. But this perception falls below certainty in fome inftances; as where an object, feen at a Dd 2 great great distance or in a fog, is perceived to be a horse, but fo indiftinctly as to make it a probability only. The perception in fuch a cafe is termed belief. Both perceptions are fundamentally of the fame nature; being simple perceptions of real exiftence. They differ only in point of diftinctness the perception of reality that makes a branch of knowledge, is so clear and diftinct as to exclude all doubt or hefitation: the perception of reality that occafions belief, being lefs clear and diftinct, makes not the existence of the object certain to us, but only probable. With respect to the fecond caufe; the existence of an abfent object, formerly feen, amounts not to a certainty; and therefore is the subject of belief only, not of knowledge. Things are in a continual flux from production to diffolution; and our fenfes are accommodated to that variable scene: a prefent object admits no doubt of its existence; but after it is removed, its exiftence becomes lefs certain, and in time finks down to a flight degree of probability. Human testimony, the third caufe, produces belief, more or lefs ftrong, accor |
