I believe in determinism and think (a la Sam Harris) that this means that my will is (at least in some important sense unfree) or (what amounts to the same thing) that I’m not morally responsible for my actions.
You are “physically responsible”, in the sense that your actions are determined by the laws of physics, whether deterministic or stochastic. The “moral responsibility” part has nothing to do with physics and everything to do with emergence: If you compare successful thriving societies with the ones less so, you will notice that apparent defections are punished in one way or another. What counts as a defection from societal norms depends heavily on the society in question.
In your example Smith and Jones are both compelled to murder by the laws of physics, however a society where Jones is not punished is less thriving on average than the one where Smith is not punished, assuming brain tumors of that kind are rare and easily diagnosable. Compatibilism is an emergent belief that helps society function when more dualist ideas are falsified by experiment. There is nothing deep about it.
You are “physically responsible”, in the sense that your actions are determined by the laws of physics, whether deterministic or stochastic. The “moral responsibility” part has nothing to do with physics and everything to do with emergence: If you compare successful thriving societies with the ones less so, you will notice that apparent defections are punished in one way or another. What counts as a defection from societal norms depends heavily on the society in question.
In your example Smith and Jones are both compelled to murder by the laws of physics, however a society where Jones is not punished is less thriving on average than the one where Smith is not punished, assuming brain tumors of that kind are rare and easily diagnosable. Compatibilism is an emergent belief that helps society function when more dualist ideas are falsified by experiment. There is nothing deep about it.