[gcthomas]

Systems where there are multiple sequential collisions are not fundamentally deterministic. There are quantum-mechanical effects in the dynamics of the collisions between the electrons in the atoms, whose positions are thoroughly probabilistic in their nature.

Quantum physics is not compatible with determinism, so any dynamical system is only precisely describable in probabilistic terms,

[meroes]

There are deterministic qm interpretations though so this can't be absolutely true.