Recognising the problems with relying on universal, positivistic methods, I still think it's better than some of the hysterical faddism that passes for policy.
New ones should be justified with reference to available evidence, not ideological commitments. It's not always possible, fair enough; but some things have been studied to death. Literally.
Why does this idea matter?
A lot of policy feels like it's generated by some kind of absurditron programme. Off the cuff stuff written on the backs of napkins, in response to Yougov polls or the latest screaming headlines has to stop.