Determinism means that the events of the world evolve in such a way that all actions must happen as determined. Your thought processes are a part of the events of the world, and as events evolve, your brain responds accordingly. Determinism has no alternatives, everything must happen as determined.
Determinism, in philosophy and science, the thesis that all events in the universe, including human decisions and actions, are causally inevitable. Determinism entails that, in a situation in which a person makes a certain decision or performs a certain action, it is impossible that he or she could have made any other decision or performed any other action. In other words, it is never true that people could have decided or acted otherwise than they actually did.''
