“The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge.”
I don't usually memorialize people, and I won't say much about Stephen Hawking either. But I heard this great quote from him on a news show.
To me this feels very similar to Eli Goldratt's 4th "pillar" of Theory of Constraints, "Never say, 'I know'."
And what does that mean? All sorts of things, but the emphasis that Goldratt was making was that there is always something new to learn and room to grow. Saying "I know" (or the opposite of "I don't know anything") blocks us from looking for opportunities and threats that can expand what we know.
Back to that Hawking quote, it is like saying that I know it all, so I don't need to learn more. The enemy of knowledge is the illusion of knowledge.
* Update 15 March 2018: A reader pointed out that Stephen Hawking didn't originally say this. It is from historian Daniel J. Boorstin.