We’ve known about ‘unknown unknowns’ for years

With Donald Rumsfeld’s book Known and Unknown making the rounds, I keep hearing the speech that gave the book its title:

[T]here are known knowns; there are things we know we know.
We also know there are known unknowns; that is to say we know there are some things we do not know.
But there are also unknown unknowns – the ones we don’t know we don’t know.

This idea is not new. I don’t know who was the first ever to use this concept, but an old usage and favorite of mine comes from the best book every written on investing, Reminiscences of a Stock Operator:

Among the hazards of speculation the happening of the unexpected–I might even say of the unexpectable–ranks high.

4 responses to “We’ve known about ‘unknown unknowns’ for years

  1. Ah, Reminiscences. I read it years ago, and I second your opinion of it. “Be right & sit tight,” as quoted in the Amazon link, just one of many fine words of advice contained within its pages.

  2. Great idea. I’d love to read ’em again.

Leave a Reply

Please log in using one of these methods to post your comment:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s