The discussion centers on whether electromagnetic radiation, particularly light, is merely a mental construct or has physical existence. It clarifies that light can be described as both particles (photons) and waves, which are oscillations in electric and magnetic fields. The wave function, a mathematical tool used to describe particles' probabilities, is debated regarding its physicality, with some arguing it represents actual oscillations of probability. Observations like Poisson's spot and interference patterns support the existence of light waves, indicating that they can be measured and are not just theoretical constructs. The conversation concludes that fully reconciling wave and particle descriptions in quantum mechanics remains an unresolved challenge.