Let’s discuss the concept of physics related to deceased grandmothers. A young man once asked a physicist whether his grandmother, whom a shaman claimed was still alive due to quantum mechanics, could be right. The physicist explained that it was not quantum mechanics but Einstein’s theory of special relativity that mattered. It pertained to the reality of time and whether the present moment was fundamentally significant.
Einstein’s theory altered the notion of time, introducing the idea that the speed of light is finite, and nothing can go faster than that. As a result, everything that one sees is actually in the past. In other words, the experience of the present moment that we all share is meaningless. This idea is known as the relativity of simultaneity, and the mathematical framework that explains it is called spacetime. According to the block universe theory, the past, present, and future exist similarly. The past, including when a grandmother was alive, exists eternally, just like the present moment.