I say in sooth, my Son, that this Extension of thy Nature is not in Violation thereof; for it is the Nature of thy Nature to grow continually. Now there is no Part of Knowledge which is foreign to thee; yet Knowledge itself is of no avail unless it be assimilated and co-ordinated into Understanding. Grow therefore, easily and spontaneously, developing all Parts equally, lest thou become a Monster. And if one Thing tempt thee overmuch, correct it by Devotion to its Opposite until Equilibrium be re-established. But seek not to grow by sudden Determination toward Things that be far from thee; only, if such a Thing come into thy Thought, construct a Bridge thereunto, and take firmly the first Step upon the Bridge. I shall explain this. Dost thou speculate upon the Motives of the Stars, and on their Elements, their Size and Weight? Then thou must first gain Knowledge of Doctrine mathematical, of Laws physical and chemical. So then first, that thou mayst understand clearly the Nature of thine whole Work, map out thy Mind, and extend its Powers from the essential outwards, from the near to the far, always with Firmness and great Thoroughness, making every Link in thy Chain equal and perfect.