. And athletes have fulfilled that motto rapidly. The winner of

the 2012 Olympic

marathon ran two hours and eight minutes. Had he been racing against

the winner of the 1904 Olympic marathon, he would have won

nearly an

hour and a

half. Now we all have this feeling that we're

just getting better as a human race, inexorably progressing, but it's not like

we've

evolved into a new

in a century. So what's going on here? I

want to take a look at what's really

progress.