Perhaps not, for science is one of the major activities of our minds, in this sense resembling art, religion or philosophy. None of these can be understood unless we consider them in relation to their past history. Science may perhaps be regarded as a mood in which we consider our world. No man is always in the same mood, and no man of science remains permanently in the scientific mood. In estimating the value of the judgments of men of science outside their own scientific department it is well to remember this, for these judgments are sometimes to be rated very low.