No physicist has ever 'seen' an 'electron'. Yet all physicists believe in the existence of electrons

No physicist has ever ‘seen’ an ‘electron’. Yet all physicists believe in the existence of electrons. An intelligent but superstitious man advance this analogy to argue that ‘ghosts’ exist even though no one has seen one. How will you refute his argument ?

It is simply a superstition that ghost exist. There is not even single authentic evidence that ghosts exists. On the other hand it is a fact that atoms exists. There are many examples to prove this fact. Atomic power plant, atomic bombs, atomic clocks etc., exist of the correlation between two parts of the statement.