would lead to unstable atoms and planetary orbits.
would make physics unpredictable because partial differential equations would lack the "hyperbolicity" property. Spacetime Dimension
: This is one of the most cited papers on this topic. Tegmark argues that our 3+1 dimensional spacetime (3 space, 1 time) is "privileged." He demonstrates that: would lead to unstable atoms and planetary orbits
might be too simple to support observers. You can read the full text at arXiv:gr-qc/9702052 . Spacetime Dimension