Let Whoever Can Do So

My Third Maxim Was To Try Always To Conquer Myself Rather Than Fortune, And To Change My Desires Rather Than The Order Of The World, And Generally To Accustom Myself To Believing That There Is Nothing Entirely In Our Power Except Our Thoughts, So That After We Have Done Our Best Regarding Things External To Us, Everything In Which We Do Not Succeed Is For Us Absolutely Impossible.

[about Pierre De Fermat] It Cannot Be Denied That He Has Had Many Exceptional Ideas, And That He Is A Highly Intelligent Man. For My Part, However, I Have Always Been Taught To Take A Broad Overview Of Things, In Order To Be Able To Deduce From Them General Rules, Which Might Be Applicable Elsewhere.

I Accept No Principles Of Physics Which Are Not Also Accepted In Mathematics.

I Can Doubt Everything, Except One Thing, And That Is The Very Fact That I Doubt. Simply Put - I Think, Therefore I Am

The Nature Of Matter, Or Body Considered In General, Consists Not In Its Being Something Which Is Hard Or Heavy Or Coloured, Or Which Affects The Senses In Any Way, But Simply In Its Being Something Which Is Extended In Length, Breadth And Depth.