CHAPTER II
ON THE CERTAIN CONSCIENCE
I. CERTAINTY in general is a firm assent of the mind to something known, without the fear of mistake. In mathematics and in other branches of exact science we can often attain absolute certainty, which rests on the evident truth of the principles which are employed to arrive at it. For anyone who is capable of following the demonstration there can be no manner of doubt that the angles of a triangle are together equal to two right angles. In the science of morality we have frequently to be content with a lower degree of certainty than this; there is often some obscurity about the principles to be applied, and human acts are not the matter of necessary and unvarying law. We have to be content with what is called moral certainty; but this again is of various degrees. I am morally certain of the existence of Berlin, though I never saw the city. Any person who doubted of its existence would be thought to be insane. The grounds on which the judgement that Berlin exists are based are so many and so strong that they leave no room for prudent doubt in the matter. In such cases we have perfect moral certainty. In other cases I may be conscious that mistake is possible but not probable, as when a man has been condemned on evidence which has satisfied a jury of intelligent men. In such cases if there can be no prudent doubt about the justice of the verdict I have moral certainty of an imperfect but real kind. If I could not safely rely in guiding my conduct on such a degree of certainty, I should have to abstain from action altogether. Ordinarily greater certainty cannot be obtained in human affairs.
2. In order to act lawfully and rightly, I must have at least moral certainty of the imperfect kind that the proposed action is honest and right. This degree of certainty will be sufficient, for ordinarily no greater can be had, as we have just seen. It is also required for right action; for if I am not at least to this extent morally certain that my action is right, I am conscious that it may (be wrong. In |this case I am bound to pause, and satisfy myself that it is right before acting; for if I do not do so my will is ready to embrace what may be wrong
