Karl Raimund Popper - was a philosopher who's work included considerable contributions to the philosophy of science and the scientific method. The contribution he is most known for is the doctrine of falsifiability.
28-July-1902 to 17-September-1994
The doctrine of falsifiability states (simplified) that in order for a theory to be a scientific theory, it must be able to be falsified by some experimental observation. As you might guess, this upsets a lot of established agendas and structures.