All Is To Be Doubted.

The Senses Deceive From Time To Time, And It Is Prudent Never To Trust Wholly Those Who Have Deceived Us Even Once.

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

Even If I Were To Suppose That I Was Dreaming And Whatever I Saw Or Imagined Was False, Yet I Could Not Deny That Ideas Were Truly In My Mind.

Variant: When It Is Not In Our Power To Follow What Is True, We Ought To Follow What Is Most Probable.

Divide Each Difficulty Into As Many Parts As Is Feasible And Necessary To Resolve It.