It Is... Easy To Be Certain. One

The Essence Of Belief Is The Establishment Of A Habit.

If We Are To Define Science, ... It Does Not Consist So Much In Knowing, Nor Even In "organized Knowledge," As It Does In Diligent Inquiry Into Truth For Truth's Sake, Without Any Sort Of Axe To Grind, Nor For The Sake Of The Delight Of Contemplating It, But From An Impulse To Penetrate Into The Reason Of Things.

Whenever A Man Acts Purposively, He Acts Under A Belief In Some Experimental Phenomenon. Consequently, The Sum Of The Experimental Phenomena That A Proposition Implies Makes Up Its Entire Bearing Upon Human Conduct.

Some Think To Avoid The Influence Of Metaphysical Errors, By Paying No Attention To Metaphysics; But Experience Shows That These Men Beyond All Others Are Held In An Iron Vice Of Metaphysical Theory, Because By Theories That They Have Never Called In Question.

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.