"The mind is not a vessel to be filled but a fire to be kindled."
I have discovered over the years though that many quotations on the web have become corrupted or miss-attributed, and so I was delighted recently to come across this site Quote Investigator.
This is what it says about the above quote from Plutarch. And here is a translation of the original text in context.
The correct analogy for the mind is not a vessel that needs filling, but wood that needs igniting -- no more -- and then it motivates one towards originality and instills the desire for truth.
Suppose someone were to go and ask his neighbors for fire and find a substantial blaze there, and just stay there continually warming himself:
that is no different from someone who goes to someone else to get to some of his rationality, and fails to realize that he ought to ignite his own flame, his own intellect,
but is happy to sit entranced by the lecture, and the words trigger only associative thinking and bring, as it were, only a flush to his cheeks and a glow to his limbs; but he has not dispelled or dispersed, in the warm light of philosophy, the internal dank gloom of his mind.
Given my views on the lecture and those of others here and here, I love the quote all the more, especially as this was written by Plutarch almost 2,000 years ago!