Hypotheses Are What We Lack The Least.

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.

A Small Error In The Former Will Produce An Enormous Error In The Latter.

What Is A Good Definition? For The Philosopher Or The Scientist, It Is A Definition Which Applies To All The Objects To Be Defined, And Applies Only To Them; It Is That Which Satisfies The Rules Of Logic. But In Education It Is Not That; It Is One That Can Be Understood By The Pupils.

Mathematical Discoveries, Small Or Great Are Never Born Of Spontaneous Generation They Always Presuppose A Soil Seeded With Preliminary Knowledge And Well Prepared By Labour, Both Conscious And Subconscious.

Experiment Is The Sole Source Of Truth.