Phrase: "Quantum leap" (Was: Uploading)

Eliezer S. Yudkowsky (
Wed, 10 Sep 1997 10:39:08 -0500

John K Clark wrote:
> It's a tangential thought but is anyone else irritated by the phrase
> "a quantum jump" when it's supposed to mean a huge change, actually it's the
> smallest possible change, anything smaller is no change at all.

(I usually hear "quantum leap", not "quantum jump".)

Depends on how you use "quantum"; it can mean either the smallest possible
unit of change (if change is quantized), or it can mean a discontinuous change
(if change is usually continuous).

Thus, when people speak of a "quantum leap", they mean a huge advance without
a lot of little advances, as if the whole technology had suddenly shifted from
one level to another, just as electrons change orbits.

The idea is not that you've jumped ahead by one quantum of change, since
technological change is continuous (to human observers). The idea is that the
technology has suddenly started behaving like a quantum system instead of a
continuous one. The leap was not a leap in a continuous system, it was a leap
in a quantum system. Hence "quantum leap".

Perfectly good terminology... I think.

--       Eliezer S. Yudkowsky

Disclaimer:  Unless otherwise specified, I'm not telling you
everything I think I know.