Imre Lakatos

It would be wrong to assume that one must stay with a research programme until it has exhausted all its heuristic power, that one must not introduce a rival programme before everybody agrees that the point of degeneration has probably been reached.

It is certain, indeed, that the sacred writers were apt to make great allowances for people with empty stomachs, and though I am well aware that the present profane ones think this very reprehensible, I venture to agree with the sacred writers.