who said what goes up must come down

The saying “what goes up must come down” is most commonly attributed to Sir Isaac Newton because it neatly sums up the everyday effect of gravity, but there is no solid evidence that he ever wrote or said this exact phrase.

Who said it first?

• The proverb itself appears to be a traditional English saying that took shape in the 1800s, inspired by the observed effects of gravity.

• Reference works describe it as a general proverb rather than a traceable quotation from a single named person.

Why people link it to Newton

• The phrase summarizes the basic idea that objects thrown upward will eventually fall due to gravity, which people naturally connect with Newton’s famous work on gravitational laws.

• Modern quote sites often label it as an “Isaac Newton quote,” which reinforces the association, even though they do not cite an original Newton text for the exact wording.

How the saying is used today

• In everyday English, it is an idiom meaning that anything that rises—prices, popularity, markets, power—will eventually fall or return to normal levels.

• It is frequently used in economic and social commentary (for example, about housing prices or financial bubbles) as a reminder that rapid growth does not last forever.

TL;DR:
No single verified person “coined” the exact line, but it developed as an English proverb based on gravity and is popularly (though loosely) linked to Isaac Newton.

Information gathered from public forums or data available on the internet and portrayed here.