>we see 'new evidence' stories almost every day that flush whatever last week's 'wisdom' was.

I guess the process you are talking about involves creating a new model which is able to account for the causal relationship for a larger set of observations, compared to the previous model. In this way, the previous model can be either flushed, or if the conditions under which it fails are known, we can use it for specific cases. Isn't physics prone to the same effect, only to a lesser frequency? Which might be worrisome, because if the opportunity to revise a model comes every 100 years, that might mean that you'll spend your whole life interpreting the world through an inferior model.