Levinthal's paradox

Etymology
After, who remarked upon it in 1969.

Proper noun

 * 1) The observation that, because of the very large number of degrees of freedom in an unfolded polypeptide chain, the molecule has an astronomically large number of possible conformations, and therefore sequentially sampling all the possible conformations is not practical, yet most small proteins fold spontaneously on a millisecond or even microsecond timescale.