The A theory and B theory of time

The A theory of time posits that only the present moment is real—future events are not yet existing, and past events no longer exist—so time flows from past to future. The B theory argues that all points in time—past, present, and future—are equally real and existing, akin to different places in space; thus, time does not flow but is a static landscape. In essence, A theory emphasizes the passage of time, while B theory views all times as equally existent, challenging our everyday experience of a flowing timeline.