The dilemma of determinism is the claim that if determinism is true, our actions are controlled by preceding events and thus we are not free; and that if indeterminism is true, our actions are random and we are likewise not free; and that as determinism and indeterminism exhaust the logical possibilities[1], free will is thus logically impossible.
Various philosophical positions provide various responses to this argument, including:
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This argument is found in the philosophical works of many current philosophers, both those who deny libertarian free will, and those who defend it. It is known under various names. Peter van Inwagen divides it into two distinct parts, the "Consequence Argument"[2] (if determinism is true, we are not free) and the "Mind Argument"[3] (if our actions are random, we are not morally responsible).[4]Galen Strawson called it the "Basic Argument" (an infinite regress in which our actions are determined by character and our character determined by prior actions).[5] John Martin Fischer calls it the "Dilemma of Determinism."[6] Robert Kane describes it as the "Ascent and Descent of Incompatibility Mountain."[7]
Steven Pinker's One-sentence Version[8] summarizes the view of the different variations of Incompatibilism:
a random event does not fit the concept of free will any more than a lawful one does, and could not serve as the long-sought locus of moral responsibility.
Derk Pereboom's version[9]
Let us now consider the libertarians, who claim that we have a capacity for indeterministically free action, and that we are thereby morally responsible. According to one libertarian view, what makes actions free is just their being constituted (partially) of indeterministic natural events. Lucretius, for example, maintains that actions are free just in virtue of being made up partially of random swerves in the downward paths of atoms. These swerves, and the actions they underlie, are random (at least) in the sense that they are not determined by any prior state of the universe.
If quantum theory is true, the position and momentum of micro-particles exhibit randomness in this same sense, and natural indeterminacy of this sort might also be conceived as the metaphysical foundation of indeterministically free action. But natural indeterminacies of these types cannot, by themselves, account for freedom of the sort required for moral responsibility.
As has often been pointed out, such random physical events are no more within our control than are causally determined physical events, and thus, we can no more be morally responsible for them than, in the indeterminist opinion, we can be for events that are causally determined.
Colin McGinn's "New Mysterian" Version[10]
The argument is exceedingly familiar, and runs as follows. Either determinism is true or it is not. If it is true, then all our chosen actions are uniquely necessitated by prior states of the world, just like every other event. But then it cannot be the case that we could have acted otherwise, since this would require a possibility determinism rules out. Once the initial conditions are set and the laws fixed, causality excludes genuine freedom.
On the other hand, if indeterminism is true, then, though things could have happened otherwise, it is not the case that we could have chosen otherwise, since a merely random event is no kind of free choice. That some events occur causelessly, or are not subject to law, or only to probabilistic law, is not sufficient for those events to be free choices.
Thus one horn of the dilemma represents choices as predetermined happenings in a predictable causal sequence, while the other construes them as inexplicable lurches to which the universe is randomly prone. Neither alternative supplies what the notion of free will requires, and no other alternative suggests itself. Therefore freedom is not possible in any kind of possible world. The concept contains the seeds of its own destruction.
Paul Russell's Version[11]
...the well-known dilemma of determinism. One horn of this dilemma is the argument that if an action was caused or necessitated, then it could not have been done freely, and hence the agent is not responsible for it. The other horn is the argument that if the action was not caused, then it is inexplicable and random, and thus it cannot be attributed to the agent, and hence, again, the agent cannot be responsible for it. In other words, if our actions are caused, then we cannot be responsible for them; if they are not caused, we cannot be responsible for them. Whether we affirm or deny necessity and determinism, it is impossible to make any coherent sense of moral freedom and responsibility.
Randolph Clarke's Version
Accounts of free will purport to tell us what is required if we are to be free agents, individuals who, at least sometimes when we act, act freely. Libertarian accounts, of course, include a requirement of indeterminism of one sort or another somewhere in the processes leading to free actions. But while proponents of such views take determinism to preclude free will, indeterminism is widely held to be no more hospitable. An undetermined action, It is said would be random or arbitrary. It could not be rational or rationally explicable. The agent would lack control over her behavior. At best, indeterminism in the processes leading to our actions would be superfluous, adding nothing of value even if it did not detract from what we want.[12]
If the truth of determinism would preclude free will, it is far from obvious how indeterminism would help.[13]
Thomas Pink's Version[14]
There are but these two alternatives. Either an action is causally determined. Or, to the extent that it is causally undetermined, its occurrence depends on chance. But chance alone does not constitute freedom. On its own, chance comes to nothing more than randomness. And one thing does seem to be clear. Randomness, the operation of mere chance, clearly excludes control.
Ishtiyaque Haji's Version[15]
Among the grandest of philosophical puzzles is a riddle about moral responsibility. Almost all of us believe that each one of us is, has been, or will be responsible for at least some of our behavior. But how can this be so if determinism is true and all our thoughts, decisions, choices, and actions are simply droplets in a river of deterministic events that began its flow long, long before we were ever born? The specter of determinism, as it were, devours agents, for if determinism is true, then arguably we never initiate or control our actions; there is no driver in the driver's seat; we are simply one transitional link in an extended deterministic chain originating long before our time. The, puzzle is tantalizingly gripping and ever so perplexing — because even if determinism is false, responsibility seems impossible: how can we be morally accountable for behavior that issues from an "actional pathway" in which there is an indeterministic break? Such a break might free us from domination or regulation by the past, but how can it possibly help to ensure that the reins of control are now in our hands?
John Martin Fischer's Version[16]
Either causal determinism is true, or it is not. If it is true, then we would lack freedom (in the alternative-possibilities and source senses). If it is false, then we would lack freedom in that we would not select the path into the future — we would not be the source of our behavior. Indeterminism appears to entail that it is not the agent who is the locus of control.
J. J. C. Smart's Version[17]
Smart states two definitions - one for determinism and one for randomness and declares them to be exhaustive of all possibilities.
| “ | Dl. I shall state the view that there is "unbroken causal continuity" in the universe as follows. It is in principle possible to make a sufficiently precise determination of the state of a sufficiently wide region of the universe at time to, and sufficient laws of nature are in principle ascertainable to enable a superhuman calculator to be able to predict any event occurring within that region at an already given time t'.
D2. I shall define the view that "pure chance" reigns to some extent within the universe as follows. There are some events that even a superhuman calculator could not predict, however precise his knowledge of however wide a region of the universe at some previous time. For the believer in free will holds that no theory of a deterministic sort or of a pure chance sort will apply to everything in the universe: he must therefore envisage a theory of a type which is neither deterministic nor indeterministic in the senses of these words which I have specified by the two definitions DI and D2; and I shall argue that no such theory is possible. |
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P. F. Strawson's Version[18]
| “ | There is another opinion which is less frequently voiced: the opinion, it might be said, of the genuine moral sceptic. the notions of moral guilt, of blame, of moral responsibility are inherently confused and that we can see this to be so if we consider the consequences either of the truth of determinism or of its falsity. The holders of this opinion agree with the pessimists that these notions lack application if determinism is true, and add simply that they also lack it if determinism is false. | ” |
Galen Strawson's Version[19]
Strawson notes the argument is familiar and cites Henry Sidgwick's 1874 Methods of Ethics. Actually Sidgwick, who accepted the 19th century view that freedom is metaphysical, is a firm determinist and only cites the Determinism Objection[20] to free will.
| “ | It is a compelling objection. Surely we cannot be free agents, in the ordinary, strong, true-responsibility-entailing sense, if determinism is true and we and our actions are ultimately wholly determined by "causes anterior to [our] personal existence"* And surely we can no more be free if determinism is false and it is, ultimately, either wholly or partly a matter of chance or random outcome that we and our actions are as they are?
H. Sidgwick, The Methods of Ethics, p. 66. This familiar objection to the claim that we can be truly responsible agents is of course disputed (and indeed scorned) by compatibilists, but it is entirely sufficient for establishing the structure of the present discussion. |
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Thomas W. Clark[21] :
| “ | Without free will, we at first seem diminished, merely the playthings of external forces. But really, determinism hardly makes us the playthings of external forces. Rather we ARE the forces themselves, concentrated and directed in patterns whose regularities we are just beginning to discern. | ” |
Roderick Chisholm's Version[22]
The metaphysical problem of human freedom might be summarized in the following way: "Human beings are responsible agents; but this fact appears to conflict with a deterministic view of human action (the view that every event that is involved in an act is caused by some other event); and it also appears to conflict with an indeterministic view of human action (the view that the act, or some event. that is essential to the act, is not caused at all)." To solve the problem, I believe, we must make somewhat far-reaching assumptions about the self of the agent — about the man who performs the act.
Richard Taylor's version[23]
If determinism is true, as the theory of soft determinism holds it to be, all those inner states which cause my body to behave in what ever ways it behaves must arise from circumstances that existed before I was born; for the chain of causes and effects is infinite, and none could have been the least different, given those that preceded.
Both determinism and simple indeterminism are loaded with difficulties, and no one who has thought much on them can affirm either of them without some embarrassment. Simple indeterminism has nothing whatever to be said for it, except that it appears to remove the grossest difficulties of determinism, only, however, to imply perfect absurdities of its own.
Determinism, on the other hand, is at least initially plausible. Men seem to have a natural inclination to believe in it; it is, indeed, almost required for the very exercise of practical intelligence. And beyond this, our experience appears always to confirm it, so long as we are dealing with everyday facts of common experience, as distinguished from the esoteric researches of theoretical physics. But determinism, as applied to human behavior, has implications which few men can casually accept, and they appear to be implications which no modification of the theory can efface..
Robert Nozick's Version[24]
Without free will, we seem diminished, merely the playthings of external forces. How, then, can we maintain an exalted view of ourselves? Determinism seems to undercut human dignity, it seems to undermine our value.
Some would deny what this question accepts as given, and save free will by denying determinism of (some) actions. Yet if an uncaused action is a random happening, then this no more comports with human value than does determinism. Random acts and caused acts alike seem to leave us not as the valuable originators of action but as an arena, a place where things happen, whether through earlier causes or spontaneously.
Peter van Inwagen's Version
Here is an argument that I think is obvious (I don't mean it's obviously right; I mean it's one that should occur pretty quickly to any philosopher who asked himself what arguments could be found to support incompatibilism):
If determinism is true, then our acts are the consequences of the laws of nature and events in the remote past. But it is not up to us what went on before we were born, and neither is it up to us what the laws of nature are. Therefore, the consequences of these things (including our present acts) are not up to us.
I shall call this argument the Consequence Argument.[2]
[A variant argument van Inwagen called the Mind Argument] proceeds by identifying indeterminism with chance and by arguing that an act that occurs by chance, if an event that occurs by chance can be called an act, cannot be under the control of its alleged agent and hence cannot have been performed freely. Proponents of [this argument] conclude, therefore, that free will is not only compatible with determinism but entails determinism.[3]
Van Inwagen dramatized his understanding of the indeterministic brain events needed for agent causation by imagining God "replaying" a situation to create exactly the same circumstances and then arguing that decisions would reflect the indeterministic probabilities. (William James had also imagined rewinding the universe and having an alternative possibility occur.[25])
If God caused Marie's decision to be replayed a very large number of times, sometimes (in thirty percent of the replays, let us say) Marie would have agent-caused the crucial brain event and sometimes (in seventy percent of the replays, let us say) she would not have... I conclude that even if an episode of agent causation is among the causal antecedents of every voluntary human action, these episodes do nothing to undermine the prima facie impossibility of an undetermined free act.[26]
Robert Kane's Ascent and Descent Version
Kane offers what may be the most attractive version of this argument against free will, with a memorable diagram. He describes the usual determinism and randomness objections (the two horns of the Libertarian Dilemma) as the ascent and descent of what he calls "Incompatibilism Mountain."
The ascent problem is to show free will is incompatible with determinism. The descent problem is to show that free will is compatible with indeterminism.
Kane says that if free will is not compatible with determinism, it does not seem to be compatible with indeterminism either.[7]
Let us call this the "Libertarian Dilemma." Events that are undetermined, such as quantum jumps in atoms, happen merely by chance. So if free actions must be undetermined, as libertarians claim, it seems that they too would happen by chance. But how can chance events be free and responsible actions? To solve the Libertarian Dilemma, libertarians must not only show that free will is incompatible with determinism, they must also show how free will can be compatible with indeterminism.
Imagine that the task for libertarians in solving this dilemma is to ascend to the top of a mountain and get down the other side. (Call the mountain "Incompatibilist Mountain": figure 4.1). Getting to the top consists in showing that free will is incompatible with determinism. (Call it the Ascent Problem.) Getting down the other side (call it the Descent Problem) involves showing how one can make sense of a free will that requires indeterminism.[7]
Note that compatiblism with determinism has always been a great deal easier to accept than compatibilism with indeterminism. Professed "agnostics" on the truth of determinism and indeterminism implicitly equate the two difficulties, whereas there is a great asymmetry between the two. Indeterminism (irrational chance) is much more difficult to reconcile with freedom than is (causal and rational) determinism.