The circular argument about electrons sounds like something a poor science teacher or textbook writer would say. One who didn't understand much about physics or chemistry but was good enough at guessing the teacher's password to acquire a credential.

It glosses over all the physics and chemistry that went into specifying what bits of thing-space are clumped into the identifier "electron", and why physicists who searched for them believed that items in that thing space would leave certain kinds of tracks in a cloud chamber under various conditions. There was a lot of evidence based on many real experiments about electricity that led them to the implicit conditional probability estimates which make that inference legitimate.

The argument itself provides no evidence whatsoever, and encountering sentences like that in science literature is possibly the most frustrating thing about learning settled science to an aspiring rationalist. It simply assumes (and hides!) the science we are supposed to learn, and thus merely giving us another password to guess.