I love the phrase between the thought and the act. It summarizes a slightly mystical experience of humanity, the difference between willing to do something and actually doing it. It comes up in all sorts of contexts. In twitch games it explains the value of better UI for allowing the player to do what they intend (as in League of Legends quick casting). In general human affairs it describes being effective. You may think of a great product idea but ideas alone are worthless; it’s the implementation that has value. The phrase also has a second meaning it ethics, the difference between thinking of doing something vs. actually doing it.

I think the best known use of this phrase is slightly different, coming from TS Eliot’s The Hollow Men.

Between the idea
And the reality
Between the motion
And the act
Falls the Shadow

I don’t like the use of “motion” though, since in so many cases the motion is the act.

The earliest use of the phrase “between the thought and the act” I could find occurs a few years before the Eliot poem, on page 242 of the 1917 book Educational Psychology by Kate Gordon. I have no idea if that book had much reach though. I wonder if the phrase comes from an older idea, maybe Greek philosophy?

Every time I think of the phrase, I hear the Crime & The City Solution song The Adversary.