In our immediate perception electrons are not seen and their existence must be inferred.
Are we in the same position as say the ancient greeks were when they were speculating that the Earth was a sphere, in that this was inferred, but no direct observation was possible. Of course today that is no longer true, the Earth is observably seen to be a sphere by a select few.
It doesn't appear to me to be so. It's easy to imagine if only we could gain a vantage point far enough from the Earth we could see it was a sphere, but the same supposition for an electon doesn't appear to work - of course one could say if only we were small enough to directly observe an electron, and on the face of it this seems similar to the above; but whereas translations of ourselves are easily observed, the same does not go for our diminuition. We do observe animals & insects much smaller than ourselves so perhaps that could be used as a justification.
Of course we could reverse the imagined process and suppose if only we could make the electron visible to the naked eye by somehow magnifying it. In fact this is possible if not with electrons then for atoms (using an electon-scanning microscope).
But is this only making visible our inference, rather than showing existence directly? Or can the positioning of apparatus between electrons and ourselves be held to be of the same quality as between ourselves and our own eyes when viewed mechanically?
I take it we cannot assume, even though they admit a mathematical description, that electrons to exist in a platonic realm in say the same way as numbers do.