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

The superstitious man's argument commits a basic error: he equates "not seen directly with the unaided eye" with "equally unverified," but the kind of evidence for electrons and for ghosts is entirely different.

• Reproducibility: Any physicist, anywhere, with the right apparatus, can repeat J.J. Thomson's cathode-ray experiment or Millikan's oil-drop experiment and get the same result — a definite charge-to-mass ratio and a quantised charge. Ghost sightings are never reproducible under controlled conditions; they cannot be summoned on demand for independent verification.
• Quantitative prediction: The existence of the electron lets us calculate things precisely — the deflection of a beam in a magnetic field, the current in a wire, the image on an electron-microscope screen, the behaviour of transistors in every computer chip. These predictions succeed to many decimal places, over and over. There is no equivalent quantitative, falsifiable prediction that 'ghosts' allow us to make and verify.
• Independent convergent evidence: electrons show up consistently across completely different kinds of experiments (electrolysis, photoelectric effect, particle accelerators, spectroscopy) all pointing to the same particle with the same properties. Ghost claims rest on isolated, subjective, anecdotal reports that do not converge in this way. …

Distinguish 'not directly visible' from 'not scientifically verified.' List the criteria science actually uses to establish the reality of an unseen entity — reproducibility, quantitative predictive success, falsifiabilit …

• Arguing 'electrons are real because scientists say so' (appeal to authority) instead of citing the actual evidential criteria. …