Retrocausality
![Time runs left to right in this Feynman diagram of electron-positron annihilation. When interpreted to include retrocausality, the electron (marked e−) was not destroyed, instead becoming the positron (e+) and moving backward in time.](/Images/godic/202502/07/Feynmann_Diagram_Gluon_Radiation.svg2758.png")
Retrocausality (also called retro-causation, retro-chronal causation, backward causation, and similar terms) is any of several hypothetical phenomena or processes that reverse causality, allowing an effect to occur before its cause.
Retrocausality is primarily a thought experiment in philosophy of science based on elements of physics, addressing whether the future can affect the present and whether the present can affect the past. Philosophical considerations of time travel often address the same issues as retrocausality, as do treatments of the subject in fiction, although the two terms are not universally synonymous.