There are persons who regard the whole imaginable and unimaginable knowledge of mankind, past, present, and future, as a boundless plain over which they hang suspended and can look down.

Immediately beneath them there is a map spread out which represents, in the midst of the immense desert, the things they themselves know.

It is a puzzle map, like those they make for children, where each piece fits into its appointed place, and will fit nowhere else; every piece of knowledge acquired fits into the space allotted to it, and when there is a piece, that is, a fact, wanting, it is still possible to define its extent and shape by the surrounding portions, though all the details of colour and design are lacking.

These are the people who regard knowledge as a whole, harmonious, when every science and fragment of a science has its appointed station and is necessary to completeness of perfect knowledge.

I hope I have made clear to you what I mean, though I am conscious of only sketching the outlines of a distinction which I believe to be fundamental." "Of course it is fundamental.