Today's QOTD is by Caltech physcist Sean Carroll. Many people, theists and atheist alike, think that quantum indeterminacy allows for libertarian free will to take place. But this is a misunderstanding of quantum mechanics and the way probability works in it. On his blog, Carroll explains:
[I]f you want to use the lack of determinism in quantum mechanics to make room for supra-physical human volition (or, for that matter, occasional interventions by God in the course of biological evolution, as Francis Collins believes), then let’s be clear: you are not making use of the rules of quantum mechanics, you are simply violating them. Quantum mechanics doesn’t say “we don’t know what’s going to happen, but maybe our ineffable spirit energies are secretly making the choices”; it says “the probability of an outcome is the modulus squared of the quantum amplitude,” full stop. Just because there are probabilities doesn’t mean there is room for free will in that sense.