2 Determinism and free choice: a brief résumé

Imagine the following scenario. You and a group of your friends find five pounds on the street. It is too little money to hand in to the police, and too difficult to divide up equally. A happy solution is to donate it to charity and, as your walk home takes you past a charity shop, the task is entrusted to you. On the way home you stand outside the charity shop. Next to it is the off-licence. You are in an agony of indecision as to whether to do as you said you would, or spend the money on a bottle of wine. It seems that you have a free choice; it is up to you which shop you walk into. Whatever you do will be your action, and something for which you can be held responsible. If you buy the wine, and someone finds out, you will rightly be the subject of blame. (This example is adapted from Strawson, 1986)

The problem arises because the appearance of free choice (and the responsibility that follows) might not be sustainable if our world is determined. It is not clear how exactly to characterize determinism. One popular definition is that every event has a cause. Nothing happens unless there is something to make it happen. Think of any event in the world. There was some set of circumstances that existed prior to the event such that those circumstances caused that event to happen and so, in that sense, made that event inevitable.

You might think that there is one exception to determinism: namely, our own decisions. I can choose whether to go into the charity shop or the off-licence. Nothing determines that choice. Let us make an assumption: what goes on in our minds is determined by what goes on in our brains. If we call the total state of our brains a ‘brain state’, then the history of our brains is a continuous set of causes and effects moving from one brain state to another. But as our brain states determine what goes on in our minds, then what goes on in our minds is a continuous set of causes and effects. The succession of our ‘mind states’ is as causally inevitable as the succession of brain states. The appearance of a free choice is an illusion; things follow in our minds as inevitably as night follows day.

What we have, then, are two plausible lines of thought with incompatible conclusions. Faced with the choice between donating the money to charity or buying a bottle of wine it seems as if we are free to choose, and so are responsible for our choice. Faced with the argument from determinism, it seems as if we are not free to choose. Whatever we decide will simply be the effect of prior brain states, those being the effect of brain states and so on back to the beginning of time.

There are a number of issues that might already have occurred to you. First, you may have heard that scientists now believe that the universe does not simply follow a pattern of deterministic cause and effect. Quantum mechanics is a theory that is needed to deal with extremely small particles. Some people interpret this theory as indeterministic; events do not happen with causal inevitability. Thus, the ‘new physics’ shows there are indeterministic (chance) elements in the universe. This undermines the premise in our argument that all events are determined. There are at least three replies we can make to this. First, the interpretation of quantum mechanics as indeterministic is disputed (indeed, some informed opinion holds that quantum mechanics is deterministic, while it is the supposedly deterministic Newtonian mechanics that may be indeterministic (cf. Butterfield 1998). Second, the problem of free will can be posed without reference to determinism, so whether the universe is determined or not is irrelevant (Strawson 1986).

To explain these replies, and possible objections to them, would take us away from the main thrust of our current concerns. Fortunately, the third reply is sufficient to demonstrate the irrelevance of indeterminism. The argument has been that quantum mechanics shows there are chance happenings in the universe. Even if this were true, and it could be shown that my choices were the result of chance, it would not follow that they were freely chosen, because I cannot freely choose chance events. Hence, indeterminism, if anything, seems to move us further away from autonomy (Ayer 1954).

The second issue concerns predictability. If the universe is deterministic then the future is uniquely determined. This seems to imply that, if we knew the current state of the universe (the position and state of every particle) and we knew the laws of nature then we could, in principle, predict what the universe would be like at any future time. This is a consequence of determinism. However, it is worthwhile distinguishing the metaphysical from the epistemological issue. The truth of determinism would make it possible in principle to predict the future course of the universe. Given this, there is still the question of whether we could know the future, given our finite minds. The answer is, of course, that the calculations would be way beyond any human mind.

The debate over the truth of determinism has raged for centuries. This has overlapped with a second debate, between people who agree – at least, for the sake of argument – that determinism is true, but disagree over whether determinism is compatible with choosing freely. Pinning some labels on, we have the following.

Those who believe that even if determinism were true, we would still be capable of free choice, are called compatibilists: they hold determinism and free choice to be compatible. Assume (for the sake of argument) that determinism is true, and so that all our actions are caused. These choices will still divide into two sorts. The first are choices that we are forced to make by such circumstances as addiction and coercion. The second are all our choices that are not like that. The second sorts of choices are, according to the compatibilist, free. In short, compatibilists argue that free choices are contrasted with constrained choices. Whether or not determinism is true, there will still be unconstrained (and hence free) choices. Choices that we are not constrained to make, even if they are caused, are our own free choices. Hence, compatibilists hold that the truth of determinism would not undermine our status as beings capable of freedom of choice, that is, as persons.

Those who believe that if determinism is true we cannot make free choices are called incompatibilists: they hold determinism and free choice to be incompatible. Determinism wrecks all freedom of choice, whether or not the choice is otherwise constrained. If the choice between the charity shop and the off-licence is the result of a determined causal chain involving the inner workings of the brain, then this is not a choice for which the person is truly responsible. There is a clear and simple sense in which they could not have done otherwise than what they did (van Inwagen 1975). Incompatibilists who believe determinism is true, and thus that we cannot make free choices, and thus that we are not persons, we can call incompatibilist determinists. Incompatibilists who believe that we can make free choices, and thus that determinism must be false, are referred to as libertarians. For a libertarian, our actions are not the result of ‘a determined and unstoppable causal chain’. People (or ‘agents’ as they sometimes called) can step outside the causal chain and initiate actions themselves. There is a freedom that is outside the causal order; a ‘contra-causal freedom’ (Chisholm 1964). You do not need fully to assimilate all this to understand Strawson’s paper. Rather, it is to put the concerns of that paper in context. You can simply refer to the various positions outlined above as and when you need to.