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René Descartes Quotes

René Descartes was a French philosopher, mathematician, and scientist. Dubbed the father of modern western philosophy, much of subsequent Western philosophy is a response to his writings, which are studied closely to this day. A native of the Kingdom of France, he spent about 20 years of his life in the Dutch Republic after serving for a while in the Dutch States Army of Maurice of Nassau, Prince of Orange and the Stadtholder of the United Provinces. He is generally considered one of the most notable intellectual representatives of the Dutch Golden Age.

Descartes's Meditations on First Philosophy continues to be a standard text at most university philosophy departments. Descartes's influence in mathematics is equally apparent; the Cartesian coordinate system was named after him. He is credited as the father of analytical geometry, the bridge between algebra and geometry, used in the discovery of infinitesimal calculus and analysis. Descartes was also one of the key figures in the scientific revolution.

Descartes refused to accept the authority of previous philosophers. He frequently set his views apart from those of his predecessors. In the opening section of the Les passions de l'âme, a treatise on the early modern version of what are now commonly called emotions, Descartes goes so far as to assert that he will write on this topic "as if no one had written on these matters before". His best known philosophical statement is "Cogito ergo sum" , found in part IV of Discours de la méthode and §7 of part I of Principles of Philosophy .

Many elements of his philosophy have precedents in late Aristotelianism, the revived Stoicism of the 16th century, or in earlier philosophers like Augustine. In his natural philosophy, he differed from the schools on two major points: first, he rejected the splitting of corporeal substance into matter and form; second, he rejected any appeal to final ends, divine or natural, in explaining natural phenomena. In his theology, he insists on the absolute freedom of God's act of creation.

Descartes laid the foundation for 17th-century continental rationalism, later advocated by Baruch Spinoza and Gottfried Leibniz, and opposed by the empiricist school of thought consisting of Hobbes, Locke, Berkeley, and Hume. Leibniz, Spinoza and Descartes were all well-versed in mathematics as well as philosophy, and Descartes and Leibniz contributed greatly to science as well.

✵ 31. March 1596 – 11. February 1650
René Descartes photo

Works

La Géométrie
René Descartes
Rules for the Direction of the Mind
René Descartes: 47 quotes43 likes

Famous René Descartes Quotes

“It is not enough to have a good mind. The main thing is to use it well.”

René Descartes

Variant: It is not enough to have a good mind; the main thing is to use it well.
Source: Discourse on Method

“Divide each difficulty into as many parts as is feasible and necessary to resolve it.”

René Descartes

Source: Discourse on Method

“I think, therefore I am.”

René Descartes

Je pense, donc je suis.
Le Discours de la Méthode (1637)
Variant: I think, therefore I am.

“If you would be a real seeker after truth, it is necessary that at least once in your life you doubt, as far as possible, all things.”

René Descartes book Principles of Philosophy

Original Latin: Veritatem inquirenti, semel in vita de omnibus, quantum fieri potest, esse dubitandum
Variant translation: If you would be a real seeker after truth, you must at least once in your life doubt, as far as possible, all things.
Principles of Philosophy (1644)
Variant: In order to seek truth, it is necessary once in the course of our life, to doubt, as far as possible, of all things.

René Descartes Quotes about the truth

“And thus, the actions of life often not allowing any delay, it is a truth very certain that, when it is not in our power to determine the most true opinions we ought to follow the most probable.”

René Descartes

Source: Discourse on Method

“There is nothing more ancient than the truth.”

René Descartes

“The entire method consists in the order and arrangement of the things to which the mind’s eye must turn so that we can discover some truth.”

René Descartes book Rules for the Direction of the Mind

Rules for the Direction of the Mind: X.379
As quoted in [Clarke, Desmond M., 2006, Descartes : a Biography, Cambridge Press, 67, ISBN 978-0-521-82301-2]

“So blind is the curiosity by which mortals are possessed, that they often conduct their minds along unexplored routes, having no reason to hope for success, but merely being willing to risk the experiment of finding whether the truth they seek lies there.”

René Descartes book Rules for the Direction of the Mind

Rules for the Direction of the Mind: IV

René Descartes Quotes

“Mr. Clerselier has written me that you are expecting from him my Meditations… in order to present them to the queen of the land. …If I had only been as wise as they say the savages persuaded themselves that the monkeys were, I never would have become known as a maker of books: Since it is said that they imagined that the monkeys could indeed speak, if they wanted to, but that they chose not to so lest they be forced to work. And since I had not the same prudence to abstain from writing, I now have neither as much liesure nor as much peace as I would have had if I had kept quiet. But since the mistake has already been made, and since I am now known by an infinity of people at the academy, who look askance at my writings and scour them for means of harming me, I do have great hope of being known to persons of great merit, whose power and virtue could protect me.”

René Descartes

Letter to Pierre Chanut (Nov. 1, 1646) as quoted by Amir Aczel, Descartes' Secret Notebook (2005) citing René Descartes: Correspondance avec Elizabeth et autres lettres (1989) ed., Jean-Marie and M. Beysaade, pp. 245-246.

“My third maxim was to endeavor always to conquer myself rather than fortune, and change my desires rather than the order of the world.”

René Descartes book Discurso sobre o Método

Source: Discourse on Method (Rozprava o metodě)

“Common sense is the most widely shared commodity in the world, for every man is convinced that he is well supplied with it.”

René Descartes

“Conquer yourself rather than the world.”

René Descartes

“Doubt is the origin of wisdom”

René Descartes

“I desire to live in peace and to continue the life I have begun under the motto 'to live well you must live unseen”

René Descartes

Source: The Principles of Philosophy

“Masked, I advance.”

René Descartes

“It is only prudent never to place complete confidence in that by which we have even once been deceived.”

René Descartes book Meditations on First Philosophy

Variant: ... it is a mark of prudence never to place our complete trust in those who have deceived us even once.
Source: Meditations on First Philosophy

“For I found myself embarrassed with so many doubts and errors that it seemed to me that the effort to instruct myself had no effect other than the increasing discovery of my own ignorance”

René Descartes

“He who hid well, lived well.”

René Descartes

“At last I will devote myself sincerely and without reservation to the general demolition of my opinions.”

René Descartes

Source: Discourse on Method

“Let whoever can do so deceive me, he will never bring it about that I am nothing, so long as I continue to think I am something.”

René Descartes

“Because reason… is the only thing that makes us men, and distinguishes us from the beasts, I would prefer to believe that it exists, in its entirety, in each of us…”

René Descartes

“With me, everything turns into mathematics.”

René Descartes

Mais apud me omnia fiunt Mathematicè in Natura More closely translated as: but in my opinion, all things in nature occur mathematically. Note: "Mais" is French for "but" and the "but in my opinion" comes from the context of the original conversation. apud me omnia fiunt Mathematicè in Natura is in latin. Sometimes the Latin version is incorrectly quoted as Omnia apud me mathematica fiunt. Sources: Correspondence with Mersenne http://fr.wikisource.org/wiki/Page%3aDescartes_-_%C5%92uvres,_%C3%A9d._Adam_et_Tannery,_III.djvu/48 note for line 7 (1640), page 36, Die Wiener Zeit http://books.google.com/books?id=9Xh3fVZLCycC&pg=PA532&lpg=PA532&dq=%22Omnia+apud+me+mathematica+fiunt%22+original+zitat&source=bl&ots=CgQOrveRiM&sig=WFHwIK20r5vRZ66FwCaxo857LCU&hl=de&sa=X&ei=_Wf2UcHlJYbfsgaf1IHABg#v=onepage&q=%22Omnia%20apud%20me%20mathematica%20fiunt%22%20original%20zitat&f=false page 532 (2008); StackExchange Math Q/A Where did Descartes write... http://math.stackexchange.com/questions/454599/where-did-descartes-write-with-me-everything-turns-into-mathematics?noredirect=1#comment978229_454599

“Good sense is the most equitably distributed of all things because no matter how much or little a person has, everyone feels so abundantly provided with good sense that he feels no desire for more than he already possesses.”

René Descartes

“The reading of all good books is indeed like a conversation with the noblest men of past centuries who were the authors of them, nay a carefully studied conversation, in which they reveal to us none but the best of their thoughts.”

René Descartes

“I doubt, therefore I think, therefore I am.”
Cogito, ergo sum.

René Descartes

Variant: Dubito, ergo cogito, ergo sum.

(English: "I doubt, therefore I think, therefore I am")

“No doubt you know that Galileo had been convicted not long ago by the Inquisition, and that his opinion on the movement of the Earth had been condemned as heresy. Now I will tell you that all things I explain in my treatise, among which is also that same opinion about the movement of the Earth, all depend on one another, and are based upon certain evident truths. Nevertheless, I will not for the world stand up against the authority of the Church. …I have the desire to live in peace and to continue on the road on which I have started.”

René Descartes

Letter to Marin Mersenne (end of Feb., 1634) as quoted by Amir Aczel, Pendulum: Leon Foucault and the Triumph of Science (2003)

“Thus, all unknown quantities can be expressed in terms of a single quantity, whenever the problem can be constructed by means of circles and straight lines, or by conic sections, or even by some other curve of degree not greater than the third or fourth.
But I shall not stop to explain this in more detail, because I should deprive you of the pleasure of mastering it yourself, as well as of the advantage of training your mind by working over it, which is in my opinion the principal benefit to be derived from this science. Because, I find nothing here so difficult that it cannot be worked out by anyone at all familiar with ordinary geometry and with algebra, who will consider carefully all that is set forth in this treatise.”

René Descartes book La Géométrie

First Book
La Géométrie (1637)

“Staying as I am, one foot in one country and the other in another, I find my condition very happy, in that it is free.”

René Descartes

Me tenant comme je suis, un pied dans un pays et l’autre en un autre, je trouve ma condition très heureuse, en ce qu’elle est libre.
Letter to Elisabeth of Bohemia, Princess Palatine (Paris, June/July 1648)

“No more useful inquiry can be proposed than that which seeks to determine the nature and the scope of human knowledge. … This investigation should be undertaken once at least in his life by anyone who has the slightest regard for truth, since in pursuing it the true instruments of knowledge and the whole method of inquiry come to light. But nothing seems to me more futile than the conduct of those who boldly dispute about the secrets of nature … without yet having ever asked even whether human reason is adequate to the solution of these problems.”

René Descartes

Rules for the Direction of the Mind in Key Philosophical Writings (1997), pp. 29-30 http://books.google.com/books?id=jjWPe-9NPoEC&pg=PA29

“What I have given in the second book on the nature and properties of curved lines, and the method of examining them, is, it seems to me, as far beyond the treatment in the ordinary geometry, as the rhetoric of Cicero is beyond the a, b, c of children.”

René Descartes

Letter to Marin Mersenne (1637) as quoted by D. E. Smith & M. L. Latham Tr. The Geometry of René Descartes (1925)

“With me, everything turns into mathematics.
More closely translated as: but in my opinion, all things in nature occur mathematically.”
Mais apud me omnia fiunt Mathematicè in Natura

René Descartes

&quot;&quot;Mais&quot;&quot; is French for &quot;&quot;but&quot;&quot; and the &quot;&quot;but in my opinion&quot;&quot; comes from the context of the original conversation. apud me omnia fiunt Mathematicè in Natura is in latin.<br>Sometimes the Latin version is incorrectly quoted as Omnia apud me mathematica fiunt.<br>Sources: Correspondence with Mersenne http://fr.wikisource.org/wiki/Page%3aDescartes_-_%C5%92uvres,_%C3%A9d._Adam_et_Tannery,_III.djvu/48 note for line 7 (1640), page 36, Die Wiener Zeit http://books.google.com/books?id=9Xh3fVZLCycC&amp;pg=PA532&amp;lpg=PA532&amp;dq=%22Omnia+apud+me+mathematica+fiunt%22+original+zitat&amp;source=bl&amp;ots=CgQOrveRiM&amp;sig=WFHwIK20r5vRZ66FwCaxo857LCU&amp;hl=de&amp;sa=X&amp;ei=_Wf2UcHlJYbfsgaf1IHABg#v=onepage&amp;q=%22Omnia%20apud%20me%20mathematica%20fiunt%22%20original%20zitat&amp;f=false page 532 (2008); StackExchange Math Q/A Where did Descartes write... http://math.stackexchange.com/questions/454599/where-did-descartes-write-with-me-everything-turns-into-mathematics?noredirect=1#comment978229_454599

“I could give here several other ways of tracing and conceiving a series of curved lines, each curve more complex than any preceding one, but I think the best way to group together all such curves and them classify them in order, is by recognizing the fact that all points of those curves which we may call "geometric," that is, those which admit of precise and exact measurement, must bear a definite relation to all points of a straight line, and that this relation must be expressed by a single equation. If this equation contains no term of higher degree than the rectangle of two unknown quantities, or the square of one, the curve belongs to the first and simplest class, which contains only the circle, the parabola, the hyperbola, and the ellipse; but when the equation contains one or more terms of the third or fourth degree in one or both of the two unknown quantities (for it requires two unknown quantities to express the relation between two points) the curve belongs to the second class; and if the equation contains a term of the fifth or sixth degree in either or both of the unknown quantities the curve belongs to the third class, and so on indefinitely.”

René Descartes book La Géométrie

Second Book
La Géométrie (1637)

“M. Desargues puts me under obligations on account of the pains that it has pleased him to have in me, in that he shows that he is sorry that I do not wish to study more in geometry, but I have resolved to quit only abstract geometry, that is to say, the consideration of questions which serve only to exercise the mind, and this, in order to study another kind of geometry, which has for its object the explanation of the phenomena of nature… You know that all my physics is nothing else than geometry.”

René Descartes

Letter to Marin Mersenne (July 27, 1638) as quoted by Florian Cajori, A History of Mathematics (1893) letter dated in The Philosophical Writings of Descartes Vol. 3, The Correspondence (1991) ed. John Cottingham, Robert Stoothoff, Dugald Murdoch

“Discourse on the Method of Rightly Conducting the Reason, and Seeking Truth in the Sciences”

René Descartes

Le Discours de la Méthode (1637)

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