Compatibilism
Compatibilism is the thesis that free will is compatible with determinism (see the SEP entry). You don’t need the universe to be open at the seams for your actions to count as free; you just need the right kind of relationship between your will and what you do.
Why not just pick a side?
If determinism rules out freedom, then almost every actual moral and legal practice is built on a metaphysical mistake. Compatibilism is the attempt to keep the practices.
Classical compatibilists (Hobbes, Hume, Mill) reject the idea that freedom requires being able to do otherwise in a metaphysically open sense. Instead:
Free action = doing what you want without external impediment.
A determined agent acting on her own desires is free; a coerced or constrained one isn’t. Determinism is beside the point.
The conditional analysis (and why it breaks)
To save “could have done otherwise” in a deterministic world, classical compatibilists reparsed it as a conditional:
“S could have done otherwise” ≡ “If S had wanted to, she would have.”
Counterexample: Danielle (per SEP)
Danielle is psychologically incapable of wanting to touch a blond dog. The conditional “if she had wanted to, she would have” is trivially true, but she genuinely couldn’t. The analysis yields the wrong answer.
The Consequence Argument (van Inwagen) is the strongest incompatibilist attack. Informally:
- No one has control over the distant past or the laws of nature
- If determinism is true, past + laws entail every future action
- Powerlessness transfers across entailment
- So no one has control over their actions
This shifted the burden: compatibilists now have to explain what kind of control agents do have if not this one.
Modern compatibilism, two moves
Frankfurt cases attack the Principle of Alternative Possibilities (PAP). Black secretly wires Jones’s brain to force him to shoot Smith, but only if Jones wavers. Jones shoots on his own. He had no alternative, yet we hold him responsible. So responsibility doesn’t require alternatives. This opened two paths:
- Hierarchical (Frankfurt): you act freely when your first-order desires mesh with your second-order desires, when your will expresses your “true self.” The unwilling addict isn’t free; the willing one is
- Reasons-responsive (Fischer & Ravizza): you act freely when the mechanism producing your action would respond to reasons in nearby counterfactuals. Guidance control, not regulative control
SEP draws a sharp line between two notions of freedom:
- Leeway freedom: requires the ability to select among alternatives (what the Consequence Argument attacks)
- Source freedom: requires being the ultimate origin of your actions
Manipulation arguments (Pereboom, Mele) press compatibilism on the source side: if a brainwashed agent meets every compatibilist condition, why is she unfree? And if deterministic upbringing is structurally identical to manipulation, doesn’t that threaten all compatibilist agents?
My take
I already wrote in Belief.md:
“I believe that the world is deterministic, but that doesn’t matter.”
That second clause is doing all the work, and now I can name it: it’s compatibilism. The universe being closed doesn’t make my wanting fake, and it doesn’t make the difference between me acting on my desires and me being coerced go away. Those distinctions are real inside the deterministic picture.
Where I think the incompatibilists land a punch is the source side, not the leeway side. The Consequence Argument never moved me; I don’t need a metaphysical fork in the road to own my choices. But manipulation arguments genuinely bite: if “my” motivational structure was installed by upbringing + genes + causal history I didn’t choose, in what sense am I its author?
Tentative answer, in the spirit of Hume: the “ultimate source” demand is incoherent. Nothing is its own ultimate source; the demand is one of those philosophical requirements that sounds deep but can’t be satisfied by anything. I’d rather have a workable notion of authorship (reasons-responsive, hierarchical mesh) than hold out for one that nothing in the universe could meet.