[robinduckett]

So before Isaac Newton, apples would float up off the tree when they fell?

[tdehnel]

The pre-existing theory Newton needed was “things move when other things act on them.” Without that, the observation would be meaningless.

Seeing the apple fall told Newton “some unseen force is acting on the apple.”

Incidentally, this was wrong. There is no “force”, only a warping of space time.