Meditations on First Philosophy (Annotated)

by René Descartes

few would prefer what is right to what is useful,

Surely whatever I had admitted until now as most true I received either from the senses or through the senses. However, I have noticed that the senses are sometimes deceptive; and it is a mark of prudence never to place our complete trust in those who have deceived us even once.

physics, astronomy, medicine, and all the other disciplines that are dependent upon the consideration of composite things are doubtful, and that, on the other hand, arithmetic, geometry, and other such disciplines, which treat of nothing but the simplest and most general things and which are indifferent as to whether these things do or do not in fact exist, contain something certain and indubitable.