Defining the Physical. In the most straightforward sense, physicalism is the thesis that everything is physical (Stoljar 2021). The physical, in turn, is defined as encompassing any property if and only if it is the kind of property described by physical theory (Stoljar 2021). This is a theory-based conception of the physical. For example, if physical theory (or just physics) describes the property of having mass, then having mass is a physical property (Stoljar 2021). This signifies how physicalism differs from materialism, its historical precedent. Materialism was a metaphysical doctrine that tried to limit physics a priori, through conditions that matter must be “solid, inert, impenetrable and conserved, and to interact deterministically and only on contact” (Crane & Xxxxxx 1990: 186). After physics has shown that matter does not meet these conditions, materialism transformed into physicalism, the claim that the empirical world contains “just what a true complete physical science would say it contains” (Xxxxx & Xxxxxx 1990: 186). Instead of making metaphysical claims to limit what the physical is a priori, physicalists make the linguistic thesis that every statement is synonymous with some physical statement (Stoljar 2021). As Xxxxxx Xxxx (2017: 14) puts it, pure physicalism is the view that it is possible, at least in principle, to describe the complete nature of fundamental reality through the vocabulary of the physical sciences. Thus, physicalism as it is known today is an a posteriori view, based on how physical theory describes the empirical world (Xxxxx & Xxxxxx 1990: 186). While at first glance this broad definition of physicalism might seem intuitive and appealing, it faces various issues. Despite the current popularity of the view, the general question regarding theory-based conceptions of physicalism is whether there is a clear, credible, non-vacuous and non-circular definition of the physical (Crane & Xxxxxx 1990: 185). So, now, I will turn to a common objection aimed against theory-based conceptions of the physical.
