Manufactured things vary. Two screws off the same line differ by microns. Two cells of the same type differ in a thousand ways. Variation is what physical processes produce. Yet every electron ever measured has exactly the same mass, exactly the same charge, exactly the same spin. Not close. The same. To the limit of measurement, an electron here is interchangeable with an electron at the edge of the observable universe. This is so reliable that physicists treat it as a law rather than a coincidence. John Wheeler once half-joked that perhaps there is only one electron, travelling back and forth through time, appearing everywhere at once. The joke survives because the alternative — that nature independently produced an unlimited number of perfectly identical objects — is somehow stranger than the joke. There is a familiar place where this happens. In software you do not build each instance of an object by hand. You define a class once and spawn copies that reference it. Every instance is identical because every instance points at the same definition. Change the definition, change them all. An electron behaves precisely like an instance of a class. So does a photon. So does every fundamental particle. The honest reading is that the building blocks of reality are not crafted individually. They are referenced from somewhere. What that somewhere is, the physics does not say.