To examine, prove or test; scrutinize.

And he said also to the people, When ye see a cloud rise out of the west, straightway ye say, There cometh a shower; and so it is. And when ye see the south wind blow, ye say, There will be heat; and it cometh to pass. Ye hypocrites, ye can DISCERN the face of the sky and of the earth; but how is it that ye do not DISCERN this time? ( Luke 12:54-56 )