We must constantly remind ourselves that real knowledge has three dimensions, length, breadth, and depth. Our acquisitions in that noble domain should not be confined to the surface of things, but should correspond to the old law as to the tenure of land, by which possession extends up to the sky, and down to the centre of the earth. Such knowledge is the handmaid, nay, the sister of original thought.
John Broadus, On the Preparation and Delivery of Sermons, pp. 136-137