 Such a demonstration might take the following form. The all-in claim that someone could have done something at t requires that the circumstances at t are consistent with their doing that thing at t. But according to determinism, the circumstances, C, at t determine that one set of events, E, occurs at t rather than any others. That is, according to the thesis of determinism, it couldn’t be that (C &amp; not-E). Now, given that what the individual in question in fact did at t (/refrained from doing at t) is a member of E, it couldn’t have been that C and yet they failed to do it (/failed to refrain from doing it). Hence, because of C, it’s not the case that they could have avoided doing what they did (/refraining from doing it).