Hume: Liberty Is the Power to Act on the Will

The Quote

"By liberty, then, we can only mean a power of acting or not acting, according to the determinations of the will" is David Hume's canonical definition of free action. It occurs in Section VIII of An Enquiry Concerning Human Understanding (1748), in the chapter "Of Liberty and Necessity," where Hume attempts to dissolve the most celebrated dispute in philosophy by distinguishing the question of whether we are free from the question of whether our actions are caused.

Context

The passage belongs to Hume's larger argument that necessity and liberty are compatible. Hume first argues that human actions exhibit the same regularity as natural events: character, motives, and circumstances make behavior predictable in the same way and to the same degree as the operations of matter. He then argues that "necessity" in both domains is nothing but constant conjunction. Against this background, the definition of liberty as the power to act according to the will shows that the two doctrines can coexist: our actions are necessary because they follow from motives, and free because they are our own.

Meaning & Interpretation

The core of the definition is the contrast between constraint and causation. The prisoner in chains is unfree because his will cannot produce its object; the person whose actions are caused by her own desires is free, because the cause is herself. Hume is explicit that this liberty "is universally allowed to belong to everyone who is not a prisoner and in chains" — which is to say that the freedom we actually care about, the freedom presupposed by praise and blame, is a property of agents in the world, not a metaphysical break in the causal order.

Legacy

Hume's compatibilism became the dominant framework for understanding free will in the analytic tradition. It was taken up by John Stuart Mill, refined in the twentieth century by philosophers such as A. J. Ayer and Daniel Dennett, and it remains the working assumption of most moral and legal practice. Kant's dismissal of it as a "wretched subterfuge" did not dislodge it; rather, the Humean definition set the terms that even Kant's defenders must address. Every contemporary compatibilist begins from the insight that freedom is the agent's power to act on her own reasons, not the absence of causes.

Sources

1. Morris, W. E. & Brown, C. R. (2020). "David Hume." Stanford Encyclopedia of Philosophy. https://plato.stanford.edu/entries/hume/
2. Hume, D. (1748). An Enquiry Concerning Human Understanding, Section VIII. Project Gutenberg.
3. Timpe, K. (2021). "Hume's Compatibilism." Internet Encyclopedia of Philosophy. https://iep.utm.edu/hume-free/
4. McKenna, M. & Coates, D. J. (2021). "Compatibilism." Stanford Encyclopedia of Philosophy. https://plato.stanford.edu/entries/compatibilism/