This preprint presents a formal reconstruction of the Cartesian foundational system within a many-sorted first-order Hilbert framework (MSFOL). The paper introduces a minimal identity foundation, experiri est esse (“experiencing is being”), formalized as: ∀xᴱ (A (x) ↔ Ex (x) ) It is shown that existential certainty remains derivable under this identity foundation, while the characteristic Cartesian superstructure (thinking-substance identification, dualism, theological expansion) is not logically entailed. The work does not refute Descartes but demonstrates that the Cartesian system is not deductively necessary. The project is a structural necessity test, not a historical critique. Version: v1. 0ₚreprintDate: 21-02-2026
Arvin Romswinckel (2026) studied this question.