Why are solid objects solid?

Solid objects are solid because two electrons cannot share one state, a rule that comes from how a knot behaves when turned. A particle here is a knot, a twist in the way neighboring patches of the world translate each other's readings. Turn an electron's knot through a full circle and it returns with its sign flipped, and only a second full turn restores it, which is what spin one half means. Swapping two identical knots winds them exactly as one full turn does, so a swap flips the sign too. The amplitude for two electrons in one state would equal its own negative, which is zero. That is Pauli's exclusion principle, and it gives atoms their shells. A hand pressed on a table is one pattern declining to occupy a state another pattern holds.

Also in Chapter 35: What Is Anything Made Of?.