Upon a given body to generate and superinduce a new nature or new natures is the work and aim of human power. To discover the Form of a given nature, or its true difference, or its causal nature, or fount of its emanation... this is the work and aim of human knowledge.
Man, being the servant and interpreter of Nature, can do and understand so much and so much only as he has observed in fact or thought of the course of nature; beyond this he neither knows anything nor can do anything.
Even great spirits have only their five-fingers' breadth of experience - just beyond it their thinking ceases and their endless empty space and stupidity begins.
There are gems of wondrous brightness
Ofttimes lying at our feet,
And we pass them, walking thoughtless,
Down the busy, crowded street.
If we knew, our pace would slacken,
We would step more oft with care,
Lest our careless feet be treading
To the earth some jewel rare.