Men Who Believe Too Firmly

A Fact In Itself Is Nothing. It Is Valuable Only For The Idea Attached To It, Or For The Proof Which It Furnishes.

Mediocre Men Often Have The Most Acquired Knowledge. It Is In The Darker. It Is In The Darker Regions Of Science That Great Men Are Recognized; They Are Marked By Ideas Which Light Up Phenomena Hitherto Obscure And Carry Science Forward.

Progress Is Achieved By Exchanging Our Theories For New Ones Which Go Further Than The Old, Until We Find One Based On A Larger Number Of Facts. ... Theories Are Only Hypotheses, Verified By More Or Less Numerous Facts. Those Verified By The Most Facts Are The Best, But Even Then They Are Never Final, Never To Be Absolutely Believed.

The Terrain Is Everything; The Germ Is Nothing.

Effects Vary With The Conditions Which Bring Them To Pass, But Laws Do Not Vary. Physiological And Pathological States Are Ruled By The Same Forces; They Differ Only Because Of The Special Conditions Under Which The Vital Laws Manifest Themselves.