And, in fine, of false sciences I thought I knew the worth sufficiently to escape being deceived by the professions of an alchemist, the predictions … - René Descartes

seeing that our senses sometimes deceive us, I was willing to suppose that there existed nothing really such as they presented to us; and because some men err in reasoning, and fall into paralogisms, even on the simplest matters of geometry, I, convinced that I was as open to error as any other, rejected as false all the reasonings I had hitherto taken for demonstrations; and finally, when I considered that the very same thoughts (presentations) which we experience when awake may also be experienced when we are asleep, while there is at that time not one of them true, I supposed that all the objects (presentations) that had ever entered into my mind when awake, had in them no more truth than the illusions of my dreams.

Common sense is the best distributed commodity in the world, for every man is convinced that he is well supplied with it.

There is no need to allege that Descartes sat in or on a stove. A poêle is simply a room heated by an earthenware stove. Cf. E. Gilson, Discours de la méthode: texte et commentaire, 4th edition (Paris: Vrin, 1967), p. 157.