Quote by Rene Descartes, Meditations On F

There may indeed be those who would prefer to deny the existence of a God so powerful, rather than believe that all other things are uncertain. But let us not oppose them for the present, and grant that all that is here said of a God is a fable; nevertheless in whatever way they suppose that I have arrived at the state of being that I have reached -- whether they attribute it to fate or to accident, or make out that it is by a continual succession of antecedents, or by some other method -- since to err and deceive oneself is a defect, it is clear that the greater will be the probability of my being so imperfect as to deceive myself ever, as is the Author to whom they assign my origin the less powerful. To these reasons I have certainly nothing to reply, but at the end I feel constrained to confess that there is nothing in all that I formerly believed to be true, of which I cannot in some measure doubt, and that not merely through want of thought or through levity, but for reasons which are very powerful and maturely considered; so that henceforth I ought not the less carefully to refrain from giving credence to these opinions than to that which is manifestly false, if I desire to arrive at any certainty in the sciences.http://www.xs4all.nl/~maartens/philosophy/descartes/meditations/med1.html

Summary

In this quote, RenÃ© Descartes acknowledges the possibility of there being individuals who deny the existence of a powerful God. However, instead of opposing them, Descartes suggests that even if we consider God to be a myth, there are still reasons to doubt the certainty of our own beliefs. He argues that since the ability to err and deceive is a flaw, if the origin of humanity is attributed to a less powerful being, like fate or accident, then it is even more probable that we ourselves are flawed and capable of self-deception. Descartes concludes that, recognizing the powerful reasons for doubting our beliefs, we should approach all opinions with equal skepticism to attain certainty in the sciences.