The discussion centers on the concept of postulates in physical theories, which are foundational assumptions that underpin the predictions of the theory. Postulates, such as the constancy of the speed of light and the equivalence of gravitational and inertial mass, are assumed rather than derived and can be tested for correctness. The importance of an axiomatic structure in theories, particularly in nonrelativistic quantum mechanics, is highlighted, with emphasis on its six axioms and their various formulations. Different formulations, such as those by Dirac, von Neumann, and Feynman, illustrate the flexibility in expressing the same postulate, particularly regarding time evolution. Overall, the discussion emphasizes the critical role of postulates in shaping the framework of physical theories.