It’s striking that many of the continuum models of classical mathematical physics (for example, the equations describing waves, diffusion or liquid flow) are known to be mere approximations of an underlying discrete collection of atoms. Quantum-gravity research suggests that even classical spacetime breaks down on very small scales. We therefore can’t be sure that quantities that we still treat as continuous (such as spacetime, field strengths and quantum wavefunction amplitudes) aren’t mere approximations of something discrete.
