 Much discussed counterarguments against the validity of such strong reductionist approaches are qualia arguments, which emphasize the impossibility for physicalist accounts to properly incorporate the quality of the subjective experience of a mental state, the “what it is like to be” (Nagel 1974) in that state. This leads to an explanatory gap between third-person and first-person accounts for which Chalmers (1995) has coined the notion of the “hard problem of consciousness”. Another, less discussed counterargument is that the physical domain itself is not causally closed. Any solution of fundamental equations of motion (be it experimentally, numerically, or analytically) requires to fix boundary conditions and initial conditions which are not given by the fundamental laws of nature (Primas 2002). This causal gap applies to classical physics as well as quantum physics, where a basic indeterminacy due to collapse makes it even more challenging. A third class of counterarguments refer to the difficulties to include notions of temporal present and nowness in a physical description (Franck 2004, 2008; Primas 2017).