Our financial first responders were feckless, our legislators spineless and our lessons from Katrina unlearned.

NPR: Katrina's Unlearned Lessons Leave Financial Mess

No scientist working on India's nuclear programme was under any illusion that bomb-making technology, once learned, could somehow be unlearned.

ECONOMIST: India

As usual, courage and cowardice is distributed among the rich and poor, the learned and unlearned, in a haphazard manner.

FORBES: An Inquisitive Novel

Knowledge cannot be unlearned, so the best way to oppose the villains is to have lots of heroes on your side.

ECONOMIST: Synthetic biology: And man made life | The

This is a lesson easily unlearned as we mature.

FORBES: The Sequester, And The Consequence Of Crying Wolf