What is the most irreplaceable fact in science?

Richard Feynman said in Volume One of his Lectures on Physics:

If, in some cataclysm, all of scientific knowledge were to be destroyed, and only one sentence passed on to the next generation of creatures, what statement would contain the most information in the fewest words? I believe it is the atomic hypothesis that all things are made of atoms — little particles that move around in perpetual motion, attracting each other when they are a little distance apart, but repelling upon being squeezed into one another.

And I think that he’s right. (Who am I to disagree with Richard Feynman?!)

In that simple concept, one can derive a huge amount of information. You can infer a remarkable number of things, and from it, you can derive the majority, if not all, knowledge about modern physics.

The basic principle was hypothesised by Democritus in the 4th century BC, and the atom was first ‘split’ by Rutherford in 1917.

But, all of biology, all of chemistry, and all of physics could be derived from simple principle that things are made of atoms.