Sometimes One Has To Say Difficult Things,

No One Has Yet Discovered Any Warlike Purpose To Be Served By The Theory Of Numbers Or Relativity, And It Seems Unlikely That Anyone Will Do So For Many Years.

It Is A Melancholy Experience For A Professional Mathematician To Find Himself Writing About Mathematics. The Function Of A Mathematician Is To Do Something, To Prove New Theorems, To Add To Mathematics, And Not To Talk About What He Or Other Mathematicians Have Done. Statesmen Despise Publicists, Painters Despise Art-critics, And Physiologists, Physicists, Or Mathematicians Have Usually Similar Feelings: There Is No Scorn More Profound, Or On The Whole More Justifiable, Than That Of The Men Who Make For The Men Who Explain. Exposition, Criticism, Appreciation, Is Work For Second-rate Minds.

Perhaps Five Or Even Ten Per Cent Of Men Can Do Something Rather Well. It Is A Tiny Minority Who Can Do Anything Really Well, And The Number Of Men Who Can Do Two Things Well Is Negligible. If A Man Has Any Genuine Talent, He Should Be Ready To Make Almost Any Sacrifice In Order To Cultivate It To The Full.

I Am Obliged To Interpolate Some Remarks On A Very Difficult Subject: Proof And Its Importance In Mathematics. All Physicists, And A Good Many Quite Respectable Mathematicians, Are Contemptuous About Proof. I Have Heard Professor Eddington, For Example, Maintain That Proof, As Pure Mathematicians Understand It, Is Really Quite Uninteresting And Unimportant, And That No One Who Is Really Certain That He Has Found Something Good Should Waste His Time Looking For Proof.

A Science Or An Art May Be Said To Be "useful" If Its Development Increases, Even Indirectly, The Material Well-being And Comfort Of Men, It Promotes Happiness, Using That Word In A Crude And Commonplace Way.