The discussion centers on whether space can be considered a medium for the travel of photons and other waves. Participants argue that electromagnetic (EM) waves do not require a medium, as they can propagate through various substances like glass, and emphasize that space is not empty but does not function as a traditional medium. Some suggest that space could be viewed as a medium due to its lowest energy state and presence of virtual particles, while others firmly reject this notion, stating that sound requires a medium and cannot exist in a vacuum. The conversation also touches on the complexities of defining "medium" and the implications of space-time in wave propagation. Ultimately, the consensus leans towards the idea that space, while not empty, does not qualify as a medium in the conventional sense for wave travel.