Free will and determinism are polar ideals that have little to do with reality. Since neither is what it seems, their traditional opposition is misleading, if not meaningless. Determinism is a modern version of fatalism: the belief that human beings have no control over the course of events, including their own behaviour. In the modern sense, it is the idea that every event has a knowable cause.
The word determine has several meanings, however. It can mean to cause an outcome or state of a system. Or it can mean to ascertain what that state or outcome is. Finally, it can mean to insist to have one’s way (to “be determined”). The first sense represents an objective view, in which things inexorably happen whether anyone is looking or not. The second represents a subjective view, in which someone must perceive and interpret what is happening to “determine” what that is. The third sense merges paradoxically with will: your will is then as free are you are determined to be!
In physics and philosophy, determinism implies a power of things or events over each other. As Hume pointed out, we jump to that conclusion when one event follows another in time; but the supposed causal power involved is a metaphysical assumption. What we actually see is events happening in succession. On the other hand, in equations that express how things happen over time, the relations between variables are set by definition. This is convenient for predicting the future (or past) of simple systems that can effectively be idealized, as though they were machines. It works because the idealization corresponds closely enough to the reality. But it is the equations that are “deterministic,” not the natural systems they describe.
Modern determinism poses a problem for free will. Chemical events in your brain, for example, determine your behaviour and even your thoughts and feelings. In times past, however, free will for humans posed a threat to divine omnipotence. For, if God was omniscient and all-powerful, then the course of events must be both fixed and known in advance by God, leaving no room for human will. But then people could not be morally accountable for their actions.
Neither determinism nor free will exist absolutely in the abstract ways traditionally thought. What exists is the subjective experience of trying to assert will over resistant objects and opposing wills—and the experience of frustration when not succeeding. In particular, we try to assert willpower over our own bodies and their impulses. It then often seems that the body has a will of its own—which indeed it does.
What, after all, is will? The body is a self-defining, self-maintaining, self-activating organism, not an inert object like a rock or an atom. It does not simply react to outside causes, but acts on its own energy and initiative, on its own behalf. What better definition of will? On the other hand, what one casually calls one’s “self” is a psychological agent that evolved to serve the interests of the body. Its specialized job is to monitor the body’s sensory input, motor output, and internal workings on a high but isolated level. For this self to be privy to the will asserted by the body on lower levels would be as impractical as it would be for a CEO to micro-manage the affairs of a corporation.
There are conflicts of will, requiring negotiation, amid upper and lower management and labour. We can find ourselves trying to override the body’s biological programming, or the social programming it has learned—which seem “automatic” when we cannot consciously control them. In some spiritual traditions, the self is admonished to master the body like taming an animal or learning to drive. But mastering the body seems more like negotiating with God than like animal training, and not at all like controlling a machine. Whose will shall be done?