My Language Is The Sum Total Of

Theoretically, I Grant You, There Is No Possibility Of Error In Necessary Reasoning. But To Speak Thus "theoretically," Is To Uselanguage In A Pickwickian Sense. In Practice, And In Fact, Mathematics Is Not Exempt From That Liability To Error That Affects Everything That Man Does.

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.

Every Work Of Science Great Enough To Be Well Remembered For A Few Generations Affords Some Exemplification Of The Defective State Of The Art Of Reasoning Of The Time When It Was Written; And Each Chief Step In Science Has Been A Lesson In Logic.

Doubt Is An Uneasy And Dissatisfied State From Which We Struggle To Free Ourselves And Pass Into The State Of Belief; While The Latter Is A Calm And Satisfactory State Which We Do Not Wish To Avoid, Or To Change To A Belief In Anything Else.

All The Progress We Have Made In Philosophy ... Is The Result Of That Methodical Skepticism Which Is The Element Of Human Freedom.