Sure, but when you reason counterfactually about what would happen under alternate laws of physics, you somehow imagine that these laws where true. You run a si

Sure, but when you reason counterfactually about what would happen under alternate laws of physics, you somehow imagine that these laws where true. You run a simulation of an alternative reality (although you know it is just a simulation). But you need to run the mental simulation, i.e., you need to imagine. Imagining something obviously does not mean that you necessary believe it is true, but the argument is that since ppl reason counterfactual about doing things they didn't do so naturally, they confuse this imagination with their ability to actually have done differently. If you don't believe you have free will in the physical sense, then you maybe don't do this mistake, but most ppl believe they have free will. And even if you don't believe you have free will, it arguably feels like you are free to have done differently in a lot of situations (although this is ofc very subjective).