Free will
freedom of the will
The capacity to have done otherwise, or — on the competing account — to act from one's own will without external constraint. Which definition you take decides the whole dispute, because determinism threatens the first and leaves the second untouched.
In practice
Someone leaves a tradition and finds the decision was made by a book, a friendship and a bad year rather than by them. Whether that description dissolves their responsibility or just explains it is not a therapeutic question; it is this one.
The common mistake
Assuming the question is whether determinism is true. Most of the argument since Hobbes has been about what freedom means, and on the compatibilist definition the truth of determinism makes no difference to whether anyone is free.
Everything that happens has causes, including the deliberation that produced your last decision. Whether that fact removes anything worth having is the oldest live question in philosophy, and the disagreement is less about physics than about what the word free was ever supposed to mean.
The three positions
Hard determinism holds that every event is necessitated by prior causes, that human choice is no exception, and that free will is therefore an illusion — Baron d'Holbach (1770) stated it without hedging. Libertarianism holds that agents originate actions in a way not reducible to prior causes; Thomas Reid (1788) and later Roderick Chisholm (1964) developed this as agent causation, where a substance rather than an event is the cause.
Compatibilism, which is the majority position among philosophers, redefines the term. Hobbes (1651) and Hume (1748) argued that liberty means the absence of constraint on doing what you will, not the absence of causation of the will: a man is free when he can act according to his desires, even if those desires were causedHume, D. (1748). An Enquiry Concerning Human Understanding, Section VIII, 'Of Liberty and Necessity'. Hume argued the dispute is verbal and has persisted only through ambiguity: liberty is 'a power of acting or not acting, according to the determinations of the will', which is compatible with those determinations having causes.. Harry Frankfurt (1971) refined this into a hierarchical account — you act freely when your effective desire is one you want to have — and separately (1969) constructed cases in which an agent could not have done otherwise yet is plainly responsible, which undermines the principle that responsibility requires alternate possibilities.
The theological form of the argument
The problem enters Christian thought as grace against merit. Augustine, against Pelagius, argued that the will is bound and freed only by grace, a position he developed over decades from De libero arbitrio (c. 395) to the late anti-Pelagian works. The dispute was reopened directly in 1524–25, when Erasmus published De libero arbitrio and Luther answered with De servo arbitrioLuther, M. (1525). De servo arbitrio (On the Bondage of the Will). Luther told Erasmus he alone had attacked the real issue rather than 'trifles' — and held that the will is a beast ridden by either God or Satan, with no power to choose its rider., which he regarded as the only one of his books worth preserving. Luis de Molina (1588) proposed middle knowledge as a reconciliation: God knows what any free creature would do in any circumstance, and so can order the world without determining the choice. The Reformed tradition rejected it; the debate is unresolved and structurally identical to the secular one.
What the neuroscience does and does not show
Benjamin Libet (1983) found a readiness potential preceding a reported conscious decision by several hundred milliseconds, widely reported as evidence that the brain decides before you do. The interpretation has not held up well: Schurger and colleagues (2012) argued the readiness potential is stochastic drift crossing a threshold, not a decision being madeSchurger, A., Sitt, J. D. & Dehaene, S. (2012). 'An accumulator model for spontaneous neural activity prior to self-initiated movement.' PNAS 109(42). On this account the averaged readiness potential is an artefact of aligning traces to movement onset, and carries no information about a prior decision.. The deeper limitation is that the experiments concern arbitrary finger movements on no grounds, which is not the kind of decision anyone means by a free one.
The objection that bites hardest
Galen Strawson (1994) argues that moral responsibility is impossible on any account. To be responsible for what you do you must be responsible for how you are; to be responsible for how you are you must have chosen to be that way, on the basis of some prior how-you-were — and the regress does not terminate. This applies to libertarian and compatibilist accounts alike, because it is about the origin of the self rather than the causation of the act.
Peter Strawson (1962) gave the influential reply, and it changes the subject deliberately. Our practices of holding responsible rest on reactive attitudes — resentment, gratitude, indignation — that are constitutive of relating to people as people, and no metaphysical discovery could give us reason to abandon them, because the standpoint from which we would abandon them is not one we can occupy.
What it rules out
It rules out treating the question as settled by determinism, since the compatibilist definition is untouched by it. It rules out Libet as a result about deliberated choice. And it rules out the assumption that responsibility requires you could have done otherwise — Frankfurt's cases show it does not.
It does not rule out responsibility. Even on Galen Strawson's argument, the practices of praise, blame and reform continue to function and continue to change behaviour; what his argument removes is a certain kind of ultimate desert, which almost nothing in ordinary life was resting on.
Sources
Augustine (c. 395). De libero arbitrio. · Chisholm, R. (1964). 'Human Freedom and the Self.' Lindley Lecture, University of Kansas. · Erasmus, D. (1524). De libero arbitrio. · Frankfurt, H. (1969). 'Alternate Possibilities and Moral Responsibility.' Journal of Philosophy 66(23). · Frankfurt, H. (1971). 'Freedom of the Will and the Concept of a Person.' Journal of Philosophy 68(1). · Hobbes, T. (1651). Leviathan, ch. 21. · Holbach, P. H. d' (1770). Système de la Nature. · Hume, D. (1748). An Enquiry Concerning Human Understanding, VIII. · Libet, B. et al. (1983). 'Time of conscious intention to act.' Brain 106(3). · Luther, M. (1525). De servo arbitrio. · Molina, L. de (1588). Concordia liberi arbitrii cum gratiae donis. · Reid, T. (1788). Essays on the Active Powers of Man. · Schurger, A. et al. (2012). PNAS 109(42). · Strawson, G. (1994). 'The Impossibility of Moral Responsibility.' Philosophical Studies 75(1). · Strawson, P. F. (1962). 'Freedom and Resentment.' Proceedings of the British Academy 48.
Concept web
Open the full webQuestions
What is free will?
Either the capacity to have done otherwise, or the capacity to act from one's own will without external constraint. The dispute turns almost entirely on which definition is in play: determinism threatens the first and leaves the second untouched.
What is compatibilism?
The position that free will and determinism are consistent, because freedom means acting according to your own will rather than being uncaused. Hobbes (1651) and Hume (1748) argued the opposing view rests on an ambiguity; it is the majority position among philosophers today.
Do the Libet experiments disprove free will?
No. Schurger and colleagues (2012) argued the readiness potential is stochastic drift crossing a threshold rather than a decision, and the experiments concern arbitrary finger movements made on no grounds — not the deliberated choices the debate is about.
What did Luther and Erasmus disagree about?
Whether the will is free with respect to salvation. Erasmus defended a limited freedom in De libero arbitrio (1524); Luther answered in De servo arbitrio (1525) that the will is bound, and later said it was the only one of his books worth keeping.
Can you be responsible if determinism is true?
Frankfurt (1969) showed responsibility does not require the ability to do otherwise. Galen Strawson (1994) argues ultimate responsibility is impossible regardless, since it would require being responsible for how you are. Peter Strawson (1962) replied that our practices of holding responsible do not rest on the metaphysics at all.