Economics is a good example as well I believe... Up until the second half of the 20th century many economists were not basing their theories on data but rather under assumptions that we are all "rational" actors. I will concede that the 'data' was not really available until the last 50yrs anyway but the 'behavioral' movement has hopefully set Economics as a whole on a 'straight' path and no doubt the next 100yrs will show the low hanging fruit which now dangle above us.
How poetic.
EDIT - The economics example I gave was very sweeping. Just an example.