Determinism is the philosophical position that every event is caused, and is completely explained by, the preceding events. The causes, in turn, are events that were caused by earlier events. Nothing happens without there first being some event sufficient to cause it. This is a natural conclusion following from Newton's observations on the natural laws that (seem to) govern all aspects of our universe.

In most cases, we believe that an accurate description of an event includes all causes. If we want to know why the eight ball went in the corner pocket, we look at the exact force of the cue hitting the ball at a specific angle, we talk about the friction between the table and the ball, and the transfer of force between balls and the angles at which balls bounce off of the sides of the table. We generally talk about gravity and inertia and air resistance, but if the ball goes into the pocket because the ball wants to go into the pocket, well, we'd better include that too. The explanation of what happened includes all the causes, and an explanation had better include all the causes, whether we like them or not, or it simply isn't a correct explanation. Determinism is simply the blanket affirmation that this method of explaining things is the correct method, in every context.

The biggest problem with this idea is that it seems incompatible with free will. There are some sorts of 'mental events,'* which include our feelings, wants, and decisions. These events must surely be caused in the same way as physical events; you want something because you've learned that it is good, you love someone because of the way they are (and the way you are). The wants and likes and knowings come from things that have happened to you, either inside your head or out. You are the way you are because of the way other things were. An explanation of what you do is composed of an exhaustive list of causes.

The alternative may be worse; if things (including mental events) aren't caused, they are uncaused, random. This 'random' is not random in the sense that heads or tails is random; A coin flip is caused, and with enough data (and computing power), we could indeed tell if a specific coin flip is going to come up heads or tails. (This is rocket science.) The random we are talking about is a nothing-BANG-something type of random, which is quite literally impossible to predict. Needless to say, random, unpredictable, and spontaneous thoughts are not the type of 'free will' we want causing our actions.

At the moment determinism seems to fit in very well with what we know about the universe on the marco level, but quantum mechanics seems to support the idea of random events, at least in a sense. Whether this is a boon for free will is questionable, as being probabilistic is a rather unsatisfactory cross between the worst of determinism and chaos: perhaps on a quantum level we neither choose what to do nor can we predict what we might do.

* Determinism does not require that you believe in materialism, although I think most determinists are materialists. You may replace this with 'chemical events', if you like.

Regarding the argument that determinism frees us from responsibility: If we believe in determinism, then we should believe that we have responsibility for our actions. Admittedly, 'responsibility' is an abstract term, but there is nothing to be gained by saying that we don't have it. In the worst case, responsibility is simply a specific "program" we run to determine the most effective reaction to certain events.

If Determinism is true, then what we believe is not under our control (at least not in the way most of us would like to believe), but what we do is still decided by what we believe. You may not be able to decide, freely, that you should act good or bad, but you are still an agent who does make decisions, and these decisions are affected by the predicted results of the decisions. Of course, if you decide, for any reason, that you are not responsible for your actions, that will change the way you behave, whether or not you are correct. It may not, however, change the way other people view you, and will not exempt you from any of the systems that are in place to deal with people to behave in ways we don't like.

Punishment, in the sense of 'hurting' a person in order to change their behaviour, is still valid under a deterministic system. Perhaps even more valid. Revenge is not valid under determinism, but then, its not valid under any system.

"Every human being is irresistibly impelled to act to act precisely as he does act: in the eternity which preceded his birth, a chain of causes was generated which, operating under the name of motives, makes it impossible that any thought of his mind, or any action of his life, should be otherwise than what it is.... The doctrine of Necessity tends to introduce a great change into the established notions of morality.... "

Percy Bysshe Shelley, in a note attached to his poem Queen Mab

Causal determinism is the thesis that every event—in the past, present, and future—is the result of a combination of causative events ("causes"). Without exception, every event in the present and future is a consequence of events in the past; everything is the necessary result of a sequence of causes.

This may seem to be a simple and obvious thesis, but the consequences of it are significant and recondite. For, if it is true, the events of the past dictate wholly the events of the present and future, thus making these events predictable. To clarify, a hypothetical, sufficiently vast intellect which, at any given moment, knew all the forces that animate the universe and the mutual states and positions of all entities that comprise nature, would know the activity of all bodies in the universe in eternity, with no uncertainty. If the future can thus be predicted with no uncertainty, then the future is as set and unalterable as the past; any future other than the one fixed from eternity is impossible.

This would also entail that the actions of human beings are equally fixed; all of our mental states and actions are causally necessitated and it is impossible for any thought or action to be other than what it is. A person's experiences and memories, the biological and psychological compositions of the brain and of the mind, and the present stimuli that compel the individual to action, are all the necessitated effects of causes.

If free will is the freedom to choose a course of action without the restraint of necessity or coercion, this thesis seemingly forbids free will. If a person's actions are all inevitable, then it seems that it is necessary for a person in a situation to make the choice that he does, and impossible for him to make any other choice. He may deliberate extensively, the deliberation itself a product of causes, but he can only deliberate in a certain predetermined way, and can only conclude by acting in a predetermined manner.

Then, if a person is invincibly directed by causes, how can he be held morally responsible for his actions? Reasonably, a person is not held morally responsible for his actions if he had no choice in his actions. For instance, a person physically forced by another person to kill is not considered responsible for the death; it would not be possible for the person being forced to do anything but follow the function forced on him. There is no choice in the matter. Similarly, how can a person be the object of resentment or commendation if it is impossible for him to deviate from his hated or lauded course?

Alternatively, quantum theory tells us that the subatomic activities of the world are truly random, and possibly that this reality is only a single reality in the realm of infinite possible realities. If this were true, and the random events of the most basic levels may be the causes of all else, then everything, including the actions of a person, would be random. On the other hand, we can see around us that it is highly improbable or impossible for random events to manifest in the macroscopic world, apparently due to statistical smoothing. However, if a person's actions may only be saved from causal necessity by random chance, there is still no moral responsibility.

This view may appear to lead one to fatalism; the invincibility of motivations might move a person to despondency or apathy. However, this need not be so. Despite the impossibility of alternative action, causal necessity may still be reconciled with free will.

On the one hand, all the events of a person's life may be hypothetically predictable from beginning to end, and it would be impossible for a person to do anything other than what he does.

On the other hand, if a person is simply defined at any given moment as a culmination of the past, such a person would have a manner of deliberation and choice that is consistent with his desires. If given the choice, ungoverned by causal necessity, that "person," at a given moment defined by his experience and biology, would make the same decisions as the ones that are causally necessitated. Thus, the actions of a person are still voluntary; a person's will is just not originative or boundless. Thus, it cannot be said that a person is ever unnaturally forced by causes to contradict his wishes, only that, because his wishes are the result of causes, his wishes directly concur with what is causally necessitated.

Determinism can also take another form. Instead of 'physical determinism', in which the nature of matter and causality is considered, there is 'logical determinism'. This approach attempts to prove the deterministic nature of the world through logical truths alone. A logical argument for determinism follows:

Consider tomorrow's weather. Either it will rain or it will not rain. One of these must come about. So, it is either true that it will rain, or true that it will not rain. But if one is true, then it must come about - otherwise it would not be true. So there exists a true statement about tomorrow's weather, implying it is fixed and determined.

Logical Determinism is an approach that seems wrong, but it's not easy to see why. My opinion is that there has been a logical error - the argument mistakenly assumes that 'either it will rain or not rain' means the same as 'either "it will rain" is true, or "it will not rain" is true'. In fact:

A or B = True
Does not mean
A = True OR B = True

The Logical Determinist's conclusion does not follow from the premises. Even if the world were indeterministic, it would be possible for us to make statements that happened to accurately predict future events by simple coincidence. The truth value of a specific prediction (For example, A = True) is not set until the event has occured.

De*ter"min*ism (?), n. Metaph.

The doctrine that the will is not free, but is inevitably and invincibly determined by motives.

Its superior suitability to produce courage, as contrasted with scientific physical determinism, is obvious. F. P. Cobbe.