Γιατί επανέρχονται στη σκέψη μου αυτές οι συνηθισμένες απόψεις και κατακτούν την πίστη μου, σαν να τους δίνει το δικαίωμα η μακροχρόνια εξοικείωση μα… - René Descartes

I shall then suppose, not that God who is supremely good and the fountain of truth, but some evil genius not less powerful than deceitful, has employed his whole energies in deceiving me; I shall consider that the heavens, the earth, colours, figures, sound, and all other external things are nought but the illusions and dreams of which this genius has availed himself in order to lay traps for my credulity; I shall consider myself as having no hands, no eyes, no flesh, no blood, nor any senses, yet falsely believing myself to possess all these things; I shall remain obstinately attached to this idea, and if by this means it is not in my power to arrive at the knowledge of any truth, I may at least do what is in my power [i.e. suspend my judgment], and with firm purpose avoid giving credence to any false thing, or being imposed upon by this arch deceiver, however powerful and deceptive he may be.

punto de partida es la duda metódica. La duda cartesiana no es escepticismo, sino un procedimiento dialéctico de investigación, encaminado a desprender y aislar la primera verdad evidente, la primera idea clara y distinta, la primera naturaleza simple.

Finally, if there be still persons who are not sufficiently persuaded of the existence of God and of the soul, by the reasons I have adduced, I am desirous that they should know that all the other propositions, of the truth of which they deem themselves perhaps more assured, as that we have a body, and that there exist stars and an earth, and such like, are less certain;