Compatibilism

David Hume's compatibilism starts from a deliberately deflationary definition: liberty, he argued, is nothing more than a power of acting or not acting according to the determination of the will, and the only alternative to this kind of liberty is not some grander metaphysical freedom from causation but constraint, being physically prevented from doing what one wills, as in imprisonment; on this view, asking whether the will itself was caused is simply a different question from asking whether a person is free, and Hume thought the two had been wrongly conflated by disputants on both sides of the free will debate for no good reason.

Harry Frankfurt sharpened the picture considerably in the twentieth century, arguing that what makes a choice genuinely free is not merely acting on one's strongest desire, which even an addict does, but acting on a desire the person reflectively endorses at a higher level, a second-order desire about which first-order desire should move them; an addict who wishes he did not want the drug is, on Frankfurt's analysis, unfree in a specific sense even while satisfying his own immediate desire, precisely because that desire is not one he endorses on reflection. This distinction lets compatibilists explain why some caused actions feel free and others do not without ever having to deny that both were, in the end, fully caused.

Compatibilism rarely announces itself as a religious doctrine, but it does a great deal of quiet work wherever a tradition holds both that God foreordains all things and that human beings remain genuinely responsible for their choices, a combination Reformed Christian theology in particular has defended in terms strikingly close to Hume's: God's decree determines the outcome, but the human agent still acts from their own will, reasons, and character, which is exactly compatibilist freedom applied to theological determinism.

The position's critics attack from both directions at once, which is itself evidence of how carefully it tries to split the difference: hard determinists argue compatibilist freedom is not real freedom at all, only a comfortable label attached to fully determined behavior so that moral practices like praise and blame can be preserved without examination, while libertarians argue the same thing from the opposite direction, insisting that genuine responsibility requires the agent to have been able to do otherwise in the strong, causally open sense compatibilism explicitly declines to require. Compatibilists answer both by pointing to ordinary moral practice, which already excuses the coerced and the insane while holding the calm, deliberate, uncoerced agent responsible, exactly the distinction compatibilist freedom is built to track.