Part IV, Chapter 16: Of the Judgment which we should make touching Future Events
THE rules which are employed in judging of past events may easily be applied to those which are future; for, as we ought to believe that an event has probably happened when the circumstances are certain, which we know are commonly connected with that event, we ought also to believe that it probably will happen when the present circumstances are such as are commonly followed by such an effect. It is thus that doctors may judge of the good or bad termination of diseases—captains of the distant events of a war—and that we judge, in the world, of the greater part of contingent affairs.
But in relation to events in which we are engaged, and which we may bring about or prevent to some extent by our diligence in seeking or avoiding them, the majority of people fall into an illusion which is the more deceptive in proportion as it appears to them more reasonable; it is, that they regard only the greatness of the result of the advantage which they hope for, or the disadvantage which they fear, without considering at all the probability which there is of that advantageous or disadvantageous event befalling.
Thus, when they apprehend any great evil, as the loss of their livelihood or their fortune, they think it the part of prudence to neglect no precaution for preserving these; and if it is some great good, as the gain of a hundred thousand crowns, they think they act wisely in seeking to obtain it, if the hazard is a small amount, however little likelihood there may be of success.
It was by a reasoning of this kind that a princess, having heard that some persons had been crushed by the fall of a ceiling, would never afterwards enter into a house without having it previously examined; and she was so persuaded that she acted reasonably in this, that she considered all who acted otherwise imprudent.
It is this reason also, probably, which induces many persons to take such troublesome and unnecessary precautions for the preservation of their health. It is this which renders others distrustful to excess, even in the smallest things, because, having been sometimes deceived, they imagine that they will be so in all other things. It is this which attracts so many to lotteries. Is it not a most advantageous thing, say they, to gain twenty thousand crowns for a single crown? Each believes that he is the happy one to whom the prize will fall; and no one reflects, that if there be, for example, twenty thousand crowns, it will be, perhaps, thirty thousand times more probable that each individual will lose them, than that he will gain them.
The defect of this reasoning is, that in order to judge of what we ought to do in order to obtain a good and to avoid an evil, it is necessary to consider, not only the good and evil in itself, but also the probability of its happening and not happening, and to regard geometrically the proportion which all these things have, taken together, which may be illustrated by the following example: —
There are certain games in which ten persons lay down a crown each, and where one only gains the whole, and all the others lose: thus each of the players has only the chance of losing a crown, and of gaining nine by it. If we consider only the gain and loss in themselves, it might appear that all have the advantage of it; but it is necessary to consider, further, that if each may gain nine crowns, and there is only the hazard of losing one, it is also nine times more probable, in relation to each, that he will lose his crown, and not gain the nine. Thus each has for himself nine crowns to hope for, one to lose,—nine degrees of probability of losing a crown, and only one of gaining the nine, which puts the matter on a perfect equality.
All games of this kind are equitable, as far as games can be, and those which are beyond this proportion are manifestly unjust; and hence we may see that there is a manifest injustice in those kinds of games which are called lotteries, because the master of the lottery, taking generally a tenth part of the whole as his perquisite, the whole body of the players is duped, in the same way as if a man should play in an equal game,—that is to say, one in which there is as much probability of gain as of loss—ten pistoles against nine. Now, if this is disadvantageous to all the players, it is also so to each in particular, since it happens hence that the probability of loss is greater than the probability of gain—that the advantage which we hope for does not surpass the disadvantage to which we are exposed, which is that of losing what we laid down.
There is sometimes so little appearance of success in a thing, that, however advantageous it may be, and however small the stake for obtaining it, it is well not to hazard it. Thus it would be folly to play twenty sous against twenty livres, or against a kingdom, on the condition that we could gain the stake only if an infant arranging at hazard the letters from a printing-office, should compose all at once the first twenty lines of Virgil’s Eneid,—yet, without thinking of it, there is no moment of our life in which we do not hazard more than a prince would do, who should risk his kingdom by playing on that condition.
These reflections may appear trifling,—and they are so, indeed, if they stop here,—but we may turn them to very important account; and the principal use which should be derived from them is that of making us more reasonable in our hopes and fears. There are, for example, many who have an excessive terror when they hear thunder. If the thunder leads us to think of God and of death, happily we cannot think too much of it; but if it is simply the danger of being killed by the thunder which causes this excessive apprehension, it is easy to show that this is unreasonable. For of two thousand persons there is at most but one killed in this way; and we may say, indeed, there is scarcely any violent death which is less common. If, therefore, the fear of an evil ought to be proportionate, not only to its magnitude, but also to its probability, as there is scarcely any kind of death more rare than death from thunder, there is scarcely anything which ought to occasion less fear,—seeing, especially, that fear does not at all help us to avoid it.
Hence it is not only necessary to undeceive those persons who take extreme and vexatious precautions for the preservation of their life and health, by showing them that these precautions are a much greater evil, than a danger so remote as that of the accidents which they fear can be; but it is necessary, also, to disabuse all who, in their undertakings, reason in the following way:—There is danger in that business; therefore, it is bad: there is advantage in this; therefore, it is good: since it is neither the danger nor the advantage, but the proportion between them, of which we are to judge.
It is of the nature of finite things, however great they may be, to be exceeded by the smallest, if often multiplied; or if these smallest things exceed the great in probability, more than the great exceed them in magnitude. Thus the very smallest gain may exceed the greatest which can be imagined, if the small is often repeated, or if that great good is so difficult to secure, that it less exceeds the small in magnitude than the small exceeds it in facility of attainment; and the same is true of the evils which we fear,—that is to say, that the smallest evil may be more considerable than the greatest which is not infinite, if it exceed it in this proportion.
It belongs to infinite things alone, as eternity and salvation, that they cannot be equalled by any temporal advantage; and thus we ought never to place them in the balance with any of the things of the world. This is why the smallest degree of facility for the attainment of salvation is of higher value than all the blessings of the world put together; and why the slightest peril of being lost is more serious than all temporal evils, considered simply as evils.
This is enough to lead all reasonable persons to come to this conclusion, with which we will finish this Logic: that the greatest of all follies is to employ our time and our life in anything else but that which will enable us to acquire one which will never end, since all the blessings and evils of this life are nothing in comparison with those of another; and since the danger of falling into these evils, as well as the difficulty of acquiring these blessings, is very great.
Those who come to this conclusion, and who follow it out in the conduct of their life, are wise and prudent, though they reason ill in all the matters of science; and those who do not come to it, however accurate they may be in everything beside, are treated of in the Scripture as foolish and infatuated, and make a bad use of logic, of reason, and of life.