Learn English – Where did the phrase blue sky thinking come from


In a question from Stack Overflow meta, the questioner has a heading:

This is currently just blue-sky thinking

in which he's tossing around ideas and asking for feedback or a brainstorm, so they can work out what direction might be good to take.

As defined by the Collins Dictionary:

Blue-sky thinking is the activity of trying to find completely new ideas.
Some consultants are good at blue-sky thinking but cannot translate that into practical change.

creative ideas that are not limited by current thinking or beliefs

Wiktionary defines it as:

blue-sky thinking (uncountable)

(idiomatic) Thinking that is not grounded or in touch in the realities
of the present.
(idiomatic) Open-minded thinking.

I'm wondering how this phrase originated.

Best Answer

blue skies wordhistories from the 1700's.

Then in the 20th century emerged the business jargon:

blue sky thinking

Origin: Some people believe this began as a reference to casual contemplation — back in the days when you’d lie on your back, watching the clouds, pondering random thoughts. The true origin is what you’d expect in a business setting: In the early 20th century, “blue sky” was frequently applied to describe fraud — notably, financiers who would inflate and over-capitalize securities based on nothing more tangible than “blue sky and hot air.” That’s why, today, “blue-sky thinking” is sometimes also described as thinking with no basis in reality.