When things get bad enough, then something happens to correct the course. And it is for that reason that I speak of evolution as an error-making and error-correcting process. And if we can be ever so much better — ever so much slightly better — at error correcting than at error making, then we'll make it.
Jonas Salk, in "Jonas Salk, "A Wise and Good Ancestor" interview with Richard D. Heffner on The Open Mind (11 May 1985)