No physicist has ever "seen" an electron, yet, all physicists believe in existence of electrons . An intelligent but superstitious man advances this analog to argure that 'ghosts' exist even though no one has "seen" one . How will you refute his argument ?

Explanation

No physicist has every 'seen' an electron. This is true. But there is so much of evidence that establishes the
existance of electrons. On the contrary, there is headly any evidence, direct or indirect to establish the
existence of ghosts.