Incompatibilism and fatalism: reply to Loss

In a recent paper (Campbell 2007), I critique two formal versions of the consequence argument: the first argument (van Inwagen 1975; 1983: 68–78) and the third argument (van Inwagen 1983: 93–105; 2000). Previously (Campbell 2008: 269), I noted that the first and third arguments depend on two different kinds of principle. Grounding principles note our lack of ability in rendering certain types of true propositions false. Presumably, we are unable to render the laws of nature false and we are equally unable to render true propositions about the past false. Given determinism, these inabilities are then passed onto all other true propositions via transfer principles like van Inwagen's (β). I am not suggesting that all versions of the consequence argument share this structure, just that the first and third arguments have this structure. Here is my criticism (Campbell 2007). Incompatibilism holds that determinism is incompatible with the free will thesis. Incompatibilism is a non-contingent thesis: if it is true, it is necessarily true. The first and third arguments depend on contingent assumptions about the actual world, for example, that every person has a remote past, a time where the world existed but he did not. Necessary truths do not follow from contingent assumptions. Thus, the first and third arguments cannot prove incompatibilism.