Doubt Everything Or Believe Everything: These Are

Need We Add That Mathematicians Themselves Are Not Infallible?

The Advance Of Science Is Not Comparable To The Changes Of A City, Where Old Edifices Are Pitilessly Torn Down To Give Place To New, But To The Continuous Evolution Of Zoologic Types Which Develop Ceaselessly And End By Becoming Unrecognisable To The Common Sight, But Where An Expert Eye Finds Always Traces Of The Prior Work Of The Centuries Past. One Must Not Think Then That The Old-fashioned Theories Have Been Sterile And Vain.

Thus, Be It Understood, To Demonstrate A Theorem, It Is Neither Necessary Nor Even Advantageous To Know What It Means.

It May Be Appropriate To Quote A Statement Of Poincare, Who Said (partly In Jest No Doubt) That There Must Be Something Mysterious About The Normal Law Since Mathematicians Think It Is A Law Of Nature Whereas Physicists Are Convinced That It Is A Mathematical Theorem.

Thought Is Only A Flash Between Two Long Nights, But This Flash Is Everything.