I was not talking the fact that evolution is falsifiable or not.
But that in science, in reality, the theory very often comes before the observation. Just as Einstein said: 'The theory determines what we can observe'.
Here is the complete quote:
Perhaps I could put it more diplomatically by saying that is may be heuristically useful to keep in mind what one has actually observed. But on principle, it is quite wrong to try founding a theory on observable magnitudes alone. In reality, the very opposite happens. It is the theory which decides what we can observe.
Werner Heisenberg, Physics and beyond, trans. Arnold J. Pomerans (New York Harper & Row, Publishers, 1971), 63
In regards to Popper, he says that scientist do not work according to the scientific method, because to say you can start with observations but without a theory is absurd.
Maybe we could start a thread about this in ''Is it science''