According to hard determinism, environment, heredity, unconscious impulses, defense mechanisms, and other influences determine people to act the way they do; and because of that, they are not responsible for their actions. But if people are not free and thus responsible for their actions, then how can we be justified in holding people responsible? Perhaps, as the hard determinist suggests, we are justified in holding people responsible only in order to influence future behavior.
However, there are a number of theories that support the claim that human beings are free and can thus be justifiably held responsible for their actions. We will consider four of them (soft determinism, pragmatism/indeterminism, existentialism, and rational-agent theory).
Soft Determinism (also called Compatibilism and Self-determinism):
Though determinism is true, that does not rule out freedom and responsibility. In contrast to hard determinism (which claims that determinism is incompatible with freedom), soft determinism says that we are determined and are nonetheless still free. According to the soft determinist, when the individual is the cause of his or her actions, he or she is said to act freely.
There are two versions of this view: passive self-determinism and active self-determinism. Augustine, Spinoza, and Hume are proponents of the first version; Aristotle is a proponent of the second.
(I) According to passive self-determinism, freedom means being able to do what one wants to do, without (external) coercion or interference from anyone else. What one wants (as expressed by one's personality or character) is determined by external events (e.g., genetics, culture, upbringing), but as long as one is able to act consistent with the choices he/she makes, he/she is free. This position is called Compatibilism or soft determinism because it (like hard determinism) acknowledges that all events, including human actions, have causes; but it allows for free actions when the actions are caused by one's choices rather than external forces.
We generally can assume that certain motives or inclinations are behind particular actions precisely because we assume that actions are linked to choices. In fact, our laws, along with the punishments and rewards associated with them, are based on such assumptions. To blame or praise assumes actions proceed from the character of the person. If an action is coerced or done in ignorance, we may say the act is wrong but that the person is not responsible. And if a person repents and reforms his or her personality, we often forgive him or her. But we do so only because we think there is a connection between one's personality (the set of character traits defined by one's choices) and the actions that the person does based on choices. We assume that there is a definite (determining) cause behind "free" actions--namely, one's character, personality, or choices. Without such a deterministic assumption, morality itself would not make sense.
Of course, human beings often do things that do not occur as a result of their character, personality, passions, or affections. Sometimes external force or violence is the cause of human behavior, and when that happens, we say that the action is not "caused" by anything in the person. Obviously, it would make no sense to reward or punish someone when his or her actions are the result of factors other than of their own choosing, because the purpose of reward and punishment is to change behavior in the future. But if we say (as the hard determinist does) that no one ever acts freely (i.e., as a result of his or her choices), then we would be unable to make sense out of moral praise or blame. In that case, human actions would be neither good nor bad--and that is something that no honest person is willing to accept: no one really lives that way.
There are two major objections to the passive version of soft determinism:
(II) According to active self-determinism, we can ultimately choose independently of culture and past conditioning because we can be self-aware and can engage in a critique of ourselves. In short, we can transcend or "step outside" of ourselves to reflect on what we have become and decide whether we want to remain that way. This self-awareness allows us to be free to make new and creative decisions. This view is the one adopted by Aristotle.
Objections to active self-determinism:
According to Indeterminism, certain decisions and acts (namely, "free" ones) have nothing that causes them to occur; they are pure chance events. They are not causally determined by anything prior to their occurrence. The assumption that all events in nature are determined is unwarranted; indeed, chance events are perhaps even necessary to account for the diversity of things in the universe. In addition, current theoretical physics recognizes that subatomic events occur in completely random and (in principle) unpredictable ways. Since not every event is predictable, and since a completely caused (determined) event would be predictable, not every event is caused. Such indeterminacy opens up the possibility that we can really affect the future; and in this way we can be free and morally responsible.
William James: Pragmatism
Since the belief in whether we are free or determined might ultimately be irresolvable in a purely theoretical way, we have to make a practical choice about what to believe. Considering what is at stake--moral responsibility, a reason for trying to improve things in the future, a justification for regretting evil--it is perfectly rational to believe that some decisions might have no absolutely determining causes and that there are genuine options in acting--in short, that we are free. In other words, on "morally rational" grounds, indeterminism (thinking that some human actions have no specific determining causes) is preferable to determinism. At least if we adopt indeterminism (and the freedom it implies), we seem to be able to explain our experience of choice much more convincingly than if we adopt determinism.