This is a post by Markel Kortabarria (University of Barcelona).

It is a commonsense belief that reality is built from the ground up. At its base lie the fundamental building blocks that serve as a foundation for everything else. This belief is largely shaped by the dominant scientific view in physics, which suggest that every object is made up of fundamental particles. Philosophically, the view is reminiscent of the ancient atomism of Leucippus and Democritus, as well as Leibniz’s theory of monads—simple, indivisible substances that form the foundation of every other substance.