The four-dimensional block universe, supported by Einstein’s theory of relativity, is a world where past, present and future are equally real. Philosophers of time have debated about whether this makes a difference to issues like freedom, responsibility, and death. Arguing against the hopeless fatalism often associated with this theory, Nikk Effingham examines the philosophical details of the block universe and whether it truly affects our human experience.

Taffy Brodesser-Akner’s Fleishman is in Trouble is now a Hulu-filmed drama series. In it, Toby’s nine-year old son asks him about the block universe. ‘It’s a theory,’ Toby says. ‘It’s this idea that, like, all of life is happening at the same time. Like all points of existence are, I don’t know, occurring simultaneously.’ Weird as that theory may sound, it is now mainstream thinking for physicists and philosophers. You might believe, as the characters of Fleishman tacitly do, that the block universe is a meaningful and important theory—that, if it were true, we should see ourselves, our lives, and the lives of others very differently because of it.