In a word: no man does, or can pretend to, believe his senses when he has a reason against it, which is an irrefragable proof that reason is above sense and controls it. But,
XIV. The reports of sense may be taken for true, when there is no reason against it.143 Because when there is no reason not to believe, that alone is a reason for believing them. And therefore,
XV. In this case, to act according to them (i.e. as taking the informations of sense to be true) is to act according to reason and the great law of our nature.
Thus, it appears that there are two ways by which we may assure ourselves of the truth of many things,144 or at least may attain such a degree of certainty as will be sufficient to determine our practice: by reason, and by sense under the government of reason, that is, when reason supports it, or at least does not oppose it. By the former, we discover speculative truths; by the latter, or both together, matters of fact.
XVI. Where certainty is not to be had,145 probability must be substituted into the place of it: that is, it must be considered, which side of the question is the more probable.
Probability, or that which in this case may incline one to believe any proposition to be true rather than false, or anything to be rather than not to be, or the contrary, will generally show itself upon the application of these and suchlike rules:
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That may be reckoned probable, which, in the estimation of reason, appears to be more agreeable to the constitution of nature. Nobody can certainly foretell that sice-ace will come up upon two dies fairly thrown before ambs-ace: yet anyone would choose to lay the former, because in nature there are twice as many chances for that as for the other. If a strolling wolf should light upon a lamb, it is not evidently known that he will tear the lamb, but there is such a natural propension in that kind to do it, that nobody would much question the event. (This instance might have been taken from amongst men, who are generally, as far as they can be, wolves one to another.) If a parent causes his child to be instructed in the foundations of useful learning, educates him virtuously, and gives him his first impulse and direction in the way to true happiness, he will be more likely to proceed and continue in it, than he would be to hit upon it, and continue in it too, if he was left to himself to be carried away by his own passions, or the influence of those people into whose hands he might fall, the bias of the former lying towards vice, and misery in the end, and the plurality of the latter being either wicked or ignorant or both. So that the advantage, in point of probability, is on the side of good education.146 When Herodotus writes that the Egyptian priests reported the sun had, within the compass of 11,340 years, twice risen where it now sets and set where it rises,147 what is fit to be believed concerning the truth of this relation (as of many others) is easily discernable by this rule. Herodotus, possibly delighting in teratical stories, might tell what he never heard; or the passage may be an interpolation; or it may be altered in transcribing; or the priests, who pretended much to a knowledge of great antiquities, might, out of mere vanity, to show what children the Greeks were in respect of them, invent such a monstrous relation, and impose it upon them whom they thought to have not much science among them; or it might be got into their memoirs before their time, who related it to Herodotus, and so pass upon posterity, as many other fictions and legends have done. These are such things as are well known to have happened often. But, that the diurnal rotation of the earth about her axis should be inverted is a phenomenon that has never been known to happen by anybody else, either before or since; that is favored by no observation; and that cannot be without great alteration in the mundane system, or those laws by which the motions of the planets, and of our earth among the rest, are governed. That this account, then, may be false is very consistent with the humor and circumstances of mankind: but that it should be true is very inconsistent with those laws by which the motions of the celestial bodies seem to be regulated, and tend to persevere in their present courses and directions. It is therefore in nature much more probable that this account is false. The odds are on that side.
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When any observation has hitherto constantly held true, or most commonly proved to be so, it has by this acquired an established credit; the cause may be presumed to retain its former force, and the effect may be taken as probable, if in the case before us there does not appear something particular: some reason for exception. No man can demonstrate that the sun will rise again, yet everyone does, and must, act as if that was certain:148 because we apprehend no decay in the causes which bring about this appearance, nor have any other reason to mistrust the event, or think it will be otherwise a few hours hence than it has been hitherto. There is no apodictical argument to prove that any particular man will die: but yet, he must be more than mad who can presume upon immortality here, when he finds so many generations all gone, to a man, and the same enemies that have laid them prostrate still pursuing their
