Some Think To Avoid The Influence Of

Upon This First, And In One Sense This Sole, Rule Of Reason, That In Order To Learn You Must Desire To Learn, And In So Desiring Not Be Satisfied With What You Already Incline To Think, There Follows One Corollary Which Itself Deserves To Be Inscribed Upon Every Wall Of The City Of Philosophy: Do Not Block The Way Of Inquiry.

For Example, There Are Numbers Of Chemists Who Occupy Themselves Exclusively With The Study Of Dyestuffs. They Discover Facts That Are Useful To Scientific Chemistry; But They Do Not Rank As Genuine Scientific Men. The Genuine Scientific Chemist Cares Just As Much To Learn About Erbium-the Extreme Rarity Of Which Renders It Commercially Unimportant-as He Does About Iron. He Is More Eager To Learn About Erbium If The Knowledge Of It Would Do More To Complete His Conception Of The Periodic Law, Which Expresses The Mutual Relations Of The Elements.

Theology, I Am Persuaded, Derives Its Initial Impulse From A Religious Wavering; For There Is Quite As Much, Or More, That Is Mysterious And Calculated To Awaken Scientific Curiosity In The Intercourse With God, And It [is] A Problem Quite Analogous To That Of Theology.

Kepler's Discovery Would Not Have Been Possible Without The Doctrine Of Conics. Now Contemporaries Of Kepler-such Penetrating Minds As Descartes And Pascal-were Abandoning The Study Of Geometry ... Because They Said It Was So Utterly Useless. There Was The Future Of The Human Race Almost Trembling In The Balance; For Had Not The Geometry Of Conic Sections Already Been Worked Out In Large Measure, And Had Their Opinion That Only Sciences Apparently Useful Ought To Be Pursued, The Nineteenth Century Would Have Had None Of Those Characters Which Distinguish It From The Ancien Régime.

Third, Consider The Insistency Of An Idea. The Insistency Of A Past Idea With Reference To The Present Is A Quantity Which Is Less, The Further Back That Past Idea Is, And Rises To Infinity As The Past Idea Is Brought Up Into Coincidence With The Present.