The extent of knowledge

The legitimate sphere of reason is: the things of the world. Whether men know God or not, they can in any case know the things of this world; and that means, to know them aright. Even a man who does not know God properly can have a vast knowledge of the things of this world. For instance he may be an eminent scientist, or a great linguist, or a great mathematical genius. Thus, without knowing anything of the true Creator, man may know the orders and laws of the Creator, without knowing whose laws they are.—Emil Brunner, The Christian Doctrine of Creation and Redemption, 26