Indeterminism, on the contrary, says that the parts have a certain amount of loose play on one another, so that the laying down of one of them does not necessarily determine what the others shall be. It admits that possibilities may be in excess of actualities, and that things not yet revealed to our knowledge may really in themselves be ambiguous. Of two alternative futures which we conceive, both may now be really possible; and the one become impossible only at the very moment when the other excludes it by becoming real itself. Indeterminism thus denies the world to be one unbending unit of fact. It says there is a certain ultimate pluralism in it; and, so saying, it corroborates our ordinary unsophisticated view of things. To that view, actualities seem to float in a wider sea of possibilities from out of which they are chosen; and, somewhere, indeterminism says, such possibilities exist, and form a part of truth.
Determinism, on the contrary, says they exist nowhere, and that necessity on the one hand and impossibility on the other are the sole categories of the real. Possibilities that fail to get realized are, for determinism, pure illusions: they never were possibilities at all. There is nothing inchoate, it says, about this universe of ours, all that was or is or shall be actual in it having been from eternity virtually there. The cloud of alternatives our minds escort this mass of actuality withal is a cloud of sheer deceptions, to which 'impossibilities' is the only name that rightfully belongs.
The issue, it will be seen, is a perfectly sharp one, which no eulogistic terminology can smear over or wipe out. The truth must lie with one side or the other, and its lying with one side makes the other false.
The question relates solely to the existence of possibilities, in the strict sense of the term, as things that may, but need not, be. Both sides admit that a volition, for instance, has occurred. The indeterminists say another volition might have occurred in its place; the determinists swear that nothing could possibly have occurred in its place. Now, can science be called in to tell us which of these two point-blank contradicters of each other is right? Science professes to draw no conclusions but such as are based on matters of fact, things that have actually happened; but how can any amount of assurance that something actually happened give us the least grain of information as to whether another thing might or might not have happened in its place? Only facts can be proved by other facts. With things that are possibilities and not facts, facts have no concern. If we have no other evidence than the evidence of existing facts, the possibility-question must remain a mystery never to be cleared up.
And the truth is that facts practically have hardly anything to do with making us either determinists or indeterminists. Sure enough, we make a flourish of quoting facts this way or that; and if we are determinists, we talk about the infallibility with which we can predict one another's conduct; while if we are indeterminists, we lay great stress on the fact that it is just because we cannot foretell one another's conduct, either in war or statecraft or in any of the great and small intrigues and businesses of men, that life is so intensely anxious and hazardous a game. But who does not see the wretched insufficiency of this so-called objective testimony on both sides? What fills up the gaps in our minds is something not objective, not external. What divides us into possibility men and anti-possibility men is different faiths or postulates,—postulates of rationality. To this man the world seems more rational with possibilities in it,—to that man more rational with possibilities excluded; and talk as we will about having to yield to evidence, what makes us monists or pluralists, determinists or indeterminists, is at bottom always some sentiment like this.
The stronghold of the deterministic sentiment is the antipathy to the idea of chance. As soon as we begin to talk indeterminism to our friends, we find a number of them shaking their heads. This notion of alternative possibility, they say, this admission that any one of several things may come to pass, is, after all, only a roundabout name for chance; and chance is something the notion of which no sane mind can for an instant tolerate in the world. What is it, they ask, but barefaced crazy unreason, the negation of intelligibility and law? And if the slightest particle of it exist anywhere, what is to prevent the whole fabric from falling together, the stars from going out, and chaos from recommencing her topsy-turvy reign?
Remarks of this sort about chance will put an end to discussion as quickly as anything one can find. I have already told you that 'chance' was a word I wished to keep and use. Let us then examine exactly what it means, and see whether it ought to be such a terrible bugbear to us. I fancy that squeezing the thistle boldly will rob it of its sting.
The sting of the word 'chance' seems to lie in the assumption that it means something positive, and that if anything happens by chance, it must needs be something of an intrinsically irrational and preposterous sort. Now, chance means nothing of the kind. It is a purely negative and relative term,[[4]] giving us no information about that of which it is predicated, except that it happens to be disconnected with something else,—not controlled, secured, or necessitated by other things in advance of its own actual presence. As this point is the most subtile one of the whole lecture, and at the same time the point on which all the rest hinges, I beg you to pay particular attention to it. What I say is that it tells us nothing about what a thing may be in itself to call it 'chance.' It may be a bad thing, it may be a good thing. It may be lucidity, transparency, fitness incarnate, matching the whole system of other things, when it has once befallen, in an unimaginably perfect way. All you mean by calling it 'chance' is that this is not guaranteed, that it may also fall out otherwise. For the system of other things has no positive hold on the chance-thing. Its origin is in a certain fashion negative: it escapes, and says, Hands off! coming, when it comes, as a free gift, or not at all.
This negativeness, however, and this opacity of the chance-thing when thus considered ab. extra, or from the point of view of previous things or distant things, do not preclude its having any amount of positiveness and luminosity from within, and at its own place and moment. All that its chance-character asserts about it is that there is something in it really of its own, something that is not the unconditional property of the whole. If the whole wants this property, the whole must wait till it can get it, if it be a matter of chance. That the universe may actually be a sort of joint-stock society of this sort, in which the sharers have both limited liabilities and limited powers, is of course a simple and conceivable notion.
Nevertheless, many persons talk as if the minutest dose of disconnectedness of one part with another, the smallest modicum of independence, the faintest tremor of ambiguity about the future, for example, would ruin everything, and turn this goodly universe into a sort of insane sand-heap or nulliverse, no universe at all. Since future human volitions are as a matter of fact the only ambiguous things we are tempted to believe in, let us stop for a moment to make ourselves sure whether their independent and accidental character need be fraught with such direful consequences to the universe as these.