This paper examines and critiques David Chalmers's thesis of "a priori scrutability" and its role in explicating the epistemic and ontological gap between mind and body. Chalmers argues that, unlike theoretical identities (such as the identity of water and H2O) which can be conclusively and a priori deduced from a complete physical description base (PQTI), the purported identity between phenomenal and brain states lacks this property. Responding to critics like Block and Stalnaker, who maintain that this explanatory gap is ubiquitous and not exclusive to the mental domain, Chalmers employs concepts such as "application conditionals" and the condition of "conclusiveness" to preserve the asymmetry between these two forms of identity. Through a rigorous analysis of application conditionals, this research argues that while such conditionals for macroscopic concepts (e.g., water) might be a priori, they are neither conclusive nor indefeasible. Instead, they remain inherently sensitive to a posteriori information and the actualised state of the world. Consequently, the scrutability of physical theoretical identities is also necessarily inconclusive.