On The Concept of Nature (1920).
Whitehead thinks that old-timey metaphysics wrongly insists that what's fundamental in the world to be studied by science is things (substance) moving around in space and time. We don't actually experience any such thing as "substance," so on this view we end up with an uncrossable gap between the world of our experience and that of science. Whitehead wants us to start instead with what we experience, which is events, and figure out how to abstract from those to come up with time, space, objects, and motion.
By getting rid of a pre-existent space-time grid, he also thinks his way of describing nature will accord better with relativity theory, since he allows for multiple space-time frameworks. His explanation involves a lot of tortured 4-dimensional geometry and heaps of weirdly defined terms, but the regular four podcasters are mighty events (not mere people), and we will soldier on to Cleopatra's Needle and beyond!
This will all be clearer to you if you listen to Mark's introduction, then you can read more about the topic and get the book. When you're done with this, listen to the Aftershow for more discussion hosted by Stephen West.
End song: "Run Away," by Mark Lint, written in 1987 and recorded in 2005 and 2015. Read about it.
Please visit our our sponsors: Go to Harrys.com and enter the code “PEL” when you check out.
The Whitehead picture is by Sterling Bartlett.