How did they meet? By chance like everyone else. What were their names? What's that got to do with you? Where were they coming from? From the nearest place. Where were they going to? Does anyone ever really know where they are going to? What were they saying? The master wasn't saying anything and Jacques was saying that his captain used to say that everything which happens to us on this earth, both good and bad, is written up above.
Master: That's very profound.
- Denis Diderot1, opening lines from Jacques the Fatalist (1796), translation by Michael Heny
The question of 'free will' versus 'determinism' is one of the oldest and most vexed of philosophical problems, and bringing it up is not a good way to guarantee that your date will go to bed with you, although it has worked on occasion (even so, clicking here will give you better odds). To begin the discussion, let us look a little more closely at the two sides of the debate.
Determinism is a position that is sometimes also called 'predestination' or 'fatalism'. This is the belief that events are somehow determined before they happen; everything is inevitable. When anything happens, whether it's a rainstorm or an assassination, there is no way that it could have happened otherwise. Any claim about what could have happened, but didn't, is called a past counterfactual and is notoriously difficult - probably impossible - to test. This is part of why determinism is controversial.
One might express determinism metaphorically by saying that there is a book in which everything that will happen is already written, or that the future already exists in the mind of God. One might even suggest that time is an illusion - it is only our limited perspective making it appear that some things are undecided about what we naively call 'the future'. More soberly, one could express the position by saying that all events occur by necessity and never by chance.
'Fatalism' is a weak form of determinism. According to a fatalist, one's 'destiny' or 'fate' determines the important events in one's life. Whether this is set by God, by the stars or by the lines in one's palm, it is unchangeable and inevitable. One's fate might be revealed in oracles or in dreams, and one might make all manner of choices in a vain effort to dodge one's fate, but one will still end up killing one's father and marrying one's mother (provided, of course, that one is Oedipus, of mythology). Fatalism is not totally incompatible with belief in free will, and it is not the type of determinism with which this entry is concerned.
The position of free will is largely a response and a reaction to the various positions of determinism. According to a belief in free will our choices are not forced, as the path of a river is forced by its channel, but they are free. Humans clearly choose one action over another, and that choice can clearly be made any of a number of ways. Nothing forced Van Gogh to paint 'Starry Starry Night' just so - he could have chosen to apply the paint to the canvas any which way. With his free will, he chose what the painting should look like (although, interestingly, many great artists will say that they feel the least free when they are working, and that they are simply obeying the commands of their muse, or something). Free will is often not as clearly defined as determinism, and belief in free will is often based on a more or less vague feeling of being 'in control' of one's actions.
Using some of the language from above, the 'book in which everything is written' is not already complete, but is only filled in as we make choices in the world. God's mind may contain some overall plan of the universe, but there is room within that plan for humans to decide their own fates. Time is real and the future is not decided until the moment that it arrives in the present. As for necessity and chance, human choices are neither of these, but are a third category of event: freely-chosen actions.
With so many ways of talking about this problem, one might expect any debate quickly to become a labyrinth of misunderstandings, semantic tangles and complete communication breakdowns. As the history of philosophy testifies, one would be right. This entry attempts to help the curious student see through some of the confusion by separating the question into different questions, asked at different levels of analysis.
Before performing this vivisection, it will be good to clarify the concept of 'levels of analysis'. Consider that favourite of philosophical examples, a chair2. A chair, considered at a physical level of analysis, is a conglomeration of quarks and leptons, dancing through the seething quantum foam of seemingly-empty space, their motions choreographed by certain physical laws. Considered at a chemical level, a chair might be wood, plastic or metal, or some combination of materials, and it would have certain properties, such as a melting temperature. At a spiritual level, a chair is a soulless object of the world of dead matter, experienced through the venal senses, and one mustn't become too attached to it; alternately it is an expression of God's greatness, witnessed through the marvelous work done by His children, applying the intellect and talents He lovingly bestowed on them. At a psychological level, a chair may or may not remind one of one's mother, of sex or of both, and may or may not be a 'trigger' that retraumatises one into a dissociative fugue. At a functional level, a chair can be useful for burning, for propping doors open, as a weapon or as a philosophical example.
Obviously, different levels of analysis can make it possible to talk about chairs in ways we never would have imagined otherwise. Let's see what they can do for the question of free will versus determinism.
The Social Level
One could consider free will versus determinism to be a question about the individual's role in society. 'Is it determined that I must work in this paper mill, just because my father and my father's father worked here, or can I go to the city, take to the stage and be a star?' At this level, the determining force would be tradition, and the possibility of free will would be the possibility of a break with tradition.
Experience shows us that breaks with tradition are possible, and in fact rather common, in some societies. In other societies, such things almost never happen. Actually staying out of the paper mill comes down to certain questions: Does the individual recognise that different options exist? How large are the social penalties imposed by the culture for breaking tradition? How strong is that individual's willpower? How much does that bus ticket cost, anyway? The answers to these questions will determine whether the individual exercises free will against the determinations of the society's traditions.
The Historical Level
Some interpret the question of free will versus determinism as what is better known as the 'Great Men' theory versus the 'Historical Forces' theory of history. The Great Men theory states that major movements in history are due to the actions of certain great men, such as Napoleon Bonaparte3, who direct the lives of many little men, such as... someone whose name we don't remember, because he wasn't great. A proponent of the Historical Forces theory will respond that there are historical forces that determine the major events of history, and that men like Napoleon just happen to have been in the right place at the right time. Like the drop of water at the very crest of a tsunami, if it hadn't been that drop, it would have been some other.
For a thoroughly well-respected discussion, which basically comes down on the side of the Historical Forces theory, see War and Peace (1865-69) by Leo Tolstoy4, especially the 'second epilogue' where he drops the plot entirely and just rants about history for 100 pages or so. There are also a couple of good scenes with Napoleon, near the middle.
The Psychological Level
Many interpret the question of free will versus determinism at a psychological level, because that is the closest to our everyday experience. Sometimes we feel that we are acting freely, and sometimes we feel that some force compels us. What brings about this difference?
A good way to answer this question is in terms of desires. We desire certain things: money, food, sex, whatever. When some desire is strong enough, we act upon it. We might also have more complex desires about which basic desires we would like to act upon. These could be called meta-desires. When we have some meta-desire, and it is strong enough to force the ordinary desires into line, then we feel that we have acted freely. When our meta-desire is foiled by circumstances (maybe we wish to quit smoking but we're addicted, or maybe if we don't smoke, our mother will be fed to crocodiles), then we feel that we are unable to exercise our free will - we don't have enough willpower. Meta-desires may also be foiled by much more subtle psychological forces.
One nice thing about this interpretation of free will is that it is compatible with determinism. It may be completely determined by some neurological circumstances that our meta-desires get their way, but it still feels free. Another use of this interpretation is in questions of ethics - we are more willing to hold people responsible for actions performed 'of their own free will' than for actions that seem to have been compelled.
The Theological Level
This was a popular level of analysis during the Protestant Reformation in Europe, beginning in the 16th Century. At this level, the question of free will versus determinism is posed this way: God is omniscient, so he knows the future, including what we will do next. How then can we be free if He already knows what will happen? On the other hand, if God gave humans free will, then how can He still be all-knowing? This is an especially thorny problem if it is supposed that our choices in this life will lead to our salvation or damnation in the next. This question is also somewhat tied up with the problem of evil: how could a loving God allow evil to exist? On the other hand, how could we choose salvation if we could not alternatively choose evil?
The position of predestination (also called 'foreordination') states that everything really is determined by God, and that who will be saved and who will be damned are already set. Who are we to question Divine Justice?
Alternatively, God gave humans free will, but he somehow still knows what we'll choose, although it's free. If this seems like a paradox, just call it a mystery and pray more. Who are we to question Divine Logic?
Some more modern thinkers would say that there really isn't a problem, because God is either something far more subtle and interesting than He's made out to be in this argument, or doesn't exist at all. People taking either of these tacks are also prone to saying that heaven and hell are myths or allegories, and might also question the existence of evil. These people are just as susceptible to lightning strikes as the next guy...
The Physical Level
The discovery of precise laws of physics, beginning in the 17th and 18th Centuries, gave rise to a new kind of determinism - physical determinism. According to this argument, the whole world is made of particles, and each of these particles follows a trajectory that is completely determined by the forces acting upon it. Putting all of these particles together, one gets a 'clockwork universe' that, after it is wound up by the 'creator', follows a precisely-determined history with no room for deviation. As time has gone by, more and more people (though by no means everyone) have decided that the human brain is nothing more than a complex physical system and is therefore also subject to these deterministic laws. According to this view, there is 'no room for freedom', and the feeling of acting freely is just an illusion.
There are two problems with this view: it is not clear that the laws of physics are completely deterministic and, whether or not they are, it is not clear that this would compromise free will.
The first problem arises because modern physics tells us that the behaviour of particles, at a quantum level, is not deterministic but depends on probabilities. Some, such as Albert Einstein5, who famously said that 'God does not play dice' - to which Niels Bohr6 is supposed to have answered: 'Stop telling God what to do' - will answer that what appear to be probabilities in quantum physics must in fact be 'hidden variables' that we just don't know about yet, and that things can't really, ultimately, be uncertain. How to interpret the probabilities of quantum mechanics is still an open question.
The second objection, that free will is not compromised by physical determinism, can take a couple of different forms. One is to define free will at the psychological level as above and point out that it is compatible with determinism. Nobody needs to be free of the laws of physics as long as we feel in control of our actions. Another approach is to deny that the brain is simply a physical system similar to a pinball machine or a computer. This approach, which is called vitalism, asserts that there must be some non-mechanistic component to the workings of the mind. This could be a spiritual component - the soul, perhaps - or it could be some not yet described, non-deterministic force. A vitalist might argue that the known laws of physics could never produce something like self-awareness, so there must be some other ingredient. What this other ingredient might be is not certain - not knowing about a force that can make human decisions independent of physical causation doesn't mean that there is no such force, but it makes it very difficult to talk about. Humans have a hard time comprehending that there could be a cause (free will) that isn't itself caused by something prior. Philosopher Immanuel Kant (1724-1804) expressed this by saying that necessary causation is a 'regulative principle of understanding'.
The answer to the question of whether free will exists or whether our actions are determined depends upon the level of analysis at which the question is asked. To summarise:
Social level - Free will can exist, but whether the individual exercises it depends partly on social circumstances and partly on the individual's willpower.
Historical level - Free will might exist, but its effects could depend largely on 'historical forces' that are beyond one's control.
Psychological level - Free will exists for those who are able to exercise it and to overcome their emotions and base desires.
Theological level - The existence of free will is a question of belief and faith.
Physical level - It is not clear that the universe is determined, but it is also unclear whether a coherent notion of free will can be added to our scientific picture of the world.
After all this discussion, it should be clear why the question of free will versus determinism is such a vexed one and why, unlike Zeno's Paradox, it wasn't resolved long ago. When the question is posed in a general context, it is not clear what is being asked. Depending on how the question is interpreted, the discussion can be catapulted into any of a number of different fields of inquiry, each of which has its own complications. Specification of the level of analysis is important, of course, if one wishes to avoid exchanges like this:
Disputant #1: Even if reality is not completely determined at a quantum level, the brain is essentially a classical system, and there is no mechanism by which quantum mechanical probabilities can bring about what seem to us to be the 'choices' of conscious agents; if anything, they would cause us to act randomly, and nobody means by 'free will' to signify stochastic behaviour.
Disputant #2: I don't care what you say; I'm not working in that paper mill!