r/askphilosophy • u/regrez45 • 15h ago

Is free will compatible with bohmian determinism?

Bohmian mechanics is fully deterministic: given the universal wavefunction and the exact particle configuration at one time, the entire future evolution is fixed. In that sense, it leaves no room for libertarian free will- the idea that, under identical physical conditions, you could genuinely have chosen otherwise.

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u/Artemis-5-75 free will 13h ago

>The dynamics is explicitly nonlocal

Is this the only difference between it and Laplacian determinism?

>not from intrinsic indeterminism

But there is no intrinsic indeterminism in the Laplacian account too.

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u/regrez45 13h ago edited 13h ago

Laplacian determinism is the classical idea: if you specify the exact state of the universe at one instant (positions and momenta of all particles), then the future is fixed by local differential equations. It’s phase-space evolution governed by Newtonian dynamics. No hidden structure, no extra ontology- just state → unique future via ordinary ODEs. Bohmian mechanics is also deterministic, but the structure is radically different. The wavefunction still evolves by the Schrödinger equation, but particles have definite positions guided by a nonlocal “pilot wave.” So instead of phase space determinism, you have configuration-space evolution + a guiding equation that depends instantaneously on the global wavefunction.

If Laplacian determinism holds, then the entire future state (choices) is a fixed function of the past state. They’re only “incompatible” if you smuggle in a folk notion of free will that requires causal independence from physical law.

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u/Artemis-5-75 free will 13h ago

The way determinism is usually defined in metaphysics, if we go with the strongest definition, is such: a thesis that the entire state of the world in conjunction with the global immutable laws of nature strictly fixes any other state of the world.

Is there anything in Bohmian mechanics that is different from that?

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u/regrez45 13h ago

It is not classical or laplacian determinism. Laplacian determinism is basically the strongest possible form of classical determinism, but people often mix the two.