He built a machine of spinning cells to think with, got the speed of light out of it, and told you in print not to believe the machine.
He pointed a better eye at the sky and rolled bronze balls down planes until nature confessed the law of falling bodies.
He reduced falling apples and wheeling planets to one law — and demanded every cause be proved from the phenomena, or confessed unknown.
Builds a small imaginary experiment, finds the assumption nobody noticed — then spends thirty years refusing to give one up.