A thought.

[alex_antonin]

I was thinking, earlier, about going back in time and inventing the pulley, explaining how it works to them with "Pull up by pulling down, have gravity on your side." Then it occurred to me that the theory of gravity is relatively new, so I began to wonder, "How did they refer to gravity before they had a word for it?"

Think about it... gravity is such an important concept to us these days, but how did they refer to it before Newton came up with his theory of gravity?