Alfred North Whitehead
Notes
Alfred North Whitehead (1861–1947), British mathematician and philosopher, co-author with Bertrand Russell of Principia Mathematica. In Process and Reality (1929) he built a metaphysics in which the basic units of the world are "actual occasions" of experience rather than enduring bits of matter, which makes him the twentieth century's major panpsychist and the source of the term "panexperientialism" that his followers prefer. Process theology, the liberal doctrine of a god who changes and does not control, descends from him. He appears here as the most systematic version of the view that experience goes all the way down.
Wikipedia: https://en.wikipedia.org/wiki/Alfred_North_Whitehead