This is a tacit consent to the existence and traits of electrons from many different experts in the sciences. Once upon a time, the best reason for thinking that there are electrons might have been success in explanation. Lorentz explained the Faraday effect with his electron theory. Once again, Hacking argues that it is not simply talking about an entity or postulating that it exists that makes it real. The Philosophical background on real entities 1.
Some hypotheses consist of assumptions as to the minute structure and operation of bodies.
From the nature of the case of these assumptions can never be proved by direct means. Their merit is their suitability to express phenomena. They are Representative Fictions. Assertions on the structure of particles and matter must be seen as intellectual tools, but not real entities that actually exist in nature. Anti- realism about entities made sense when we did not have the knowledge or tools to be able to test for their existence.