The 'architecture of human cognition' is often described as a series of modules, yet the most sophisticated intellectual posture is one of integration. To treat the 'behavioral' as separate from the 'biological' is to create a false dichotomy that ignores the 'molecular logic' of perception. Every sensation, from a photon to a memory, is a physical event that also carries a social meaning. The practitioner who silos these domains into different 'Parts' of a treatise risks missing the 'integrated reasoning' that defines medical science. For instance, the 'stress' of a student is simultaneously an endocrine cascade and a psychological appraisal of a social context. True competence is the capacity to move between these levels of explanation without a 'tectonic shift' in one’s intellectual posture. Integration is the final word on clinical reasoning.