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So far, I have been a spectator in this theater which is the world, but I am now about to mount the stage, and I come forward masked.
Rene Descartes
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Even the mind depends so much on temperament and the disposition of one's bodily organs that, if it is possible to find a way to make people generally more wise and more skilful than they have been in the past, I believe that we should look for it in medicine. It is true that medicine as it is currently practiced contains little of much use.
Rene Descartes
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Divide each difficulty into as many parts as is feasible and necessary to resolve it.
Rene Descartes
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At last I will devote myself sincerely and without reservation to the general demolition of my opinions.
Rene Descartes
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I did not imitate the skeptics who doubt only for doubting's sake, and pretend to be always undecided; on the contrary, my whole intention was to arrive at a certainty, and to dig away the drift and the sand until I reached the rock or the clay beneath.
Rene Descartes
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Reason is nothing without imagination.
Rene Descartes
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If I found any new truths in the sciences, I can say that they follow from, or depend on, five or six principal problems which I succeeded in solving and which I regard as so many battles where the fortunes of war were on my side.
Rene Descartes
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If we possessed a thorough knowledge of all the parts of the seed of any animal (e.g. man), we could from that alone, be reasons entirely mathematical and certain, deduce the whole conformation and figure of each of its members, and, conversely if we knew several peculiarities of this conformation, we would from those deduce the nature of its seed.
Rene Descartes
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The principal use of prudence, of self-control, is that it teaches us to be masters of our passions, and to so control and guide them that the evils which they cause are quite bearable, and that we even derive joy from them all.
Rene Descartes
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It is not enough to have a good mind. The main thing is to use it well.
Rene Descartes
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The chief cause of human errors is to be found in the prejudices picked up in childhood.
Rene Descartes
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I am thinking, therefore I exist. I was a substance whose whole essence or nature is solely to think, and which does not require any place, or depend on any material thing, in order to exist. Accordingly this 'I' - that is, the soul by which I am what I am - is entirely distinct from the body, and indeed is easier to know than the body, and would not fail to be whatever it is, even if the body did not exist.
Rene Descartes
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Neither the true nor the false roots are always real; sometimes they are imaginary; that is, while we can always imagine as many roots for each equation as I have assigned, yet there is not always a definite quantity corresponding to each root we have imagined.
Rene Descartes
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By 'God', I understand, a substance which is infinite, independent, supremely intelligent, supremely powerful, and which created both myself and everything else that exists. All these attributes are such that, the more carefully I concentrate on them, the less possible it seems that they could have originated from me alone. So, from what has been said it must be concluded that God necessarily exists.
Rene Descartes
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All is to be doubted.
Rene Descartes
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But possibly I am something more than I suppose myself to be.
Rene Descartes
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I am accustomed to sleep and in my dreams to imagine the same things that lunatics imagine when awake.
Rene Descartes
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Nothing comes out of nothing.
Rene Descartes
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About Pierre de Fermat. It cannot be denied that he has had many exceptional ideas, and that he is a highly intelligent man. For my part, however, I have always been taught to take a broad overview of things, in order to be able to deduce from them general rules, which might be applicable elsewhere.
Rene Descartes
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Here I beg you to observe in passing that the scruples that prevented ancient writers from using arithmetical terms in geometry, and which can only be a consequence of their inability to perceive clearly the relation between these two subjects, introduced much obscurity and confusion into their explanations.
Rene Descartes
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... regard this body as a machine which, having been made by the hand of God, is incomparably better ordered than any machine that can be devised by man, and contains in itself movements more wonderful than those in any machine. ... it is for all practical purposes impossible for a machine to have enough organs to make it act in all the contingencies of life in the way in which our reason makes us act.
Rene Descartes
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Be that as it may, there is fixed in my mind a certain opinion of long standing, namely that there exists a God who is able to do anything and by whom I, such as I am, have been created. How do I know that he did not bring it about that there is no earth at all, no heavens, no extended thing, no shape, no size, no place, and yet bringing it about that all these things appear to me to exist precisely as they do now?
Rene Descartes
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I concluded that I might take as a general rule the principle that all things which we very clearly and obviously conceive are true: only observing, however, that there is some difficulty in rightly determining the objects which we distinctly conceive.
Rene Descartes
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... moral certainty is certainty which is sufficient to regulate our behaviour, or which measures up to the certainty we have on matters relating to the conduct of life which we never normally doubt, though we know that it is possible, absolutely speaking, that they may be false.
Rene Descartes
