A cat has energy and charge, too, but it also has many other properties besides these numbers such as its name, smell and personality—so it would sound crazy to say that the cat is a purely mathematical object completely described by those two numbers. Our elementary-particle friends, on the other hand, are completely described by their quantum numbers, and appear to have no intrinsic properties at all besides these numbers! In this sense, we’ve now come full circle back to Plato’s idea: the fundamental Legos out of which everything is made appear to be purely mathematical in nature, having no
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