The discussion centers on the feasibility of simulating a universe with sentient beings, particularly focusing on the challenges of simulating light and sight. Key points include the need for a method by which a viewer perceives objects in the simulation, whether through external calculations or internal representations. The conversation explores the implications of programming light and fundamental particles, suggesting that a simulation could either directly represent quantum systems or use classical methods to approximate them. It is noted that a simulation might not need to calculate every detail of the universe continuously, as the uncertainty principle allows for approximations based on relevant observations. The idea of a geometric "cone of sight" is proposed, where only observable elements are rendered, while unobserved areas remain inactive. Ultimately, the conversation highlights that simulating human perception could be achieved through a universal model of the brain, processing information in a way that aligns with quantum mechanics, suggesting that massive simulations of the universe may not be necessary for a coherent experience.