  In this PhD thesis the ancient question of determinism ('Does every event
have a cause ?') will be re-examined. In the philosophy of science and physics
communities the orthodox position states that the physical world is
indeterministic: quantum events would have no causes but happen by irreducible
chance. Arguably the clearest theorem that leads to this conclusion is Bell's
theorem. The commonly accepted 'solution' to the theorem is 'indeterminism', in
agreement with the Copenhagen interpretation. Here it is recalled that
indeterminism is not really a physical but rather a philosophical hypothesis,
and that it has counterintuitive and far-reaching implications. At the same
time another solution to Bell's theorem exists, often termed 'superdeterminism'
or 'total determinism'. Superdeterminism appears to be a philosophical position
that is centuries and probably millennia old: it is for instance Spinoza's
determinism. If Bell's theorem has both indeterministic and deterministic
solutions, choosing between determinism and indeterminism is a philosophical
question, not a matter of physical experimentation, as is widely believed. If
it is impossible to use physics for deciding between both positions, it is
legitimate to ask which philosophical theories are of help. Here it is argued
that probability theory - more precisely the interpretation of probability - is
instrumental for advancing the debate. It appears that the hypothesis of
determinism allows to answer a series of precise questions from probability
theory, while indeterminism remains silent for these questions. From this point
of view determinism appears to be the most reasonable assumption, after all.
