Abstract
2. The Contingency and A posteriority Constraint: A formulation of the thesis must make physicalism come out contingent and a posteriori. First, physicalism is a contingent truth, if it is a truth. This means that physicalism could have been false, i.e. there are counterfactual worlds in which physicalism is false, for example, counterfactual worlds in which there are miracle -performing angels.[9] Moreover, if physicalism is true, our knowledge of its truth is a posteriori. This is to say that there are ways the world could turn out to be such that physicalism is false. For example, if there are miracle -performing angels, then physicalism is false. So there are worlds considered as actual in which physicalism is false.[10] For short, call this ‘the a posteriority constraint’.[11].