If a particle has size, what is it composed of? And if the components have size, what are they composed of? and so on, ad infinitum. The infinite regress forces us to accept the counter-intuitive notion that particles have no size and that size is a macroscopic illusion that arises from the way groups of particles interact.
Louis Savain, More Nasty Little Truths About Physics
generalism.
the ism of all isms.