21 quotes
In order to seek truth, it is necessary once in the course of our life, to doubt, as far as possible, of all things.
Principles of Philosophy (1644)
I was not, thank heaven, in a condition which compelled me to make merchandise of Science for the bettering of my fortune.
I suppose the body to be nothing but a statue or machine made of earth, which God forms with the explicit intention of making it as much as possible like us.
Le Homme (The Treatise on Man) (1662)
If you would be a real seeker after truth, you must at least once in your life doubt, as far as possible, all things.
The two operations of our understanding, intuition and deduction, on which alone we have said we must rely in the acquisition of knowledge.
Key Philosophical Writings (1997)
Study to sever pleasure from vice.
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.
Thinking is another attribute of the soul; and here I discover what properly belongs to myself. This alone is inseparable from me. I am—I exist: this is certain.
Meditations on First Philosophy (1641)
It is a truth very certain that, when it is not in our power to determine what is true, we ought to follow what is most probable
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.
Good sense is of all things in the world the most equally distributed, for everybody thinks he is so well supplied with it that even those most difficult to please in all other matters never desire more of it than they already possess.
Discours de la Méthode (1637)
Mais apud me omnia fiunt Mathematicè in Natura
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.
[T]he power of forming a good judgment and of distinguishing the true from the false, which is properly speaking what is called Good sense or Reason, is by nature equal in all men.
The whole time of my life may be divided into an infinity of parts, each of which is in no way dependent on any other; and, accordingly, because I was in existence a short time ago, it does not follow that I must now exist, unless in this moment some cause create me anew as it were,—that is, conserve me.
Meditations on First Philosophy (1641)
Sciences contained in books, (such of them at least as are made up of probable reasonings, without demonstrations), composed as they are of the opinions of many different individuals massed together, are farther removed from truth than the simple inferences which a man of good sense using his natural and unprejudiced judgment draws respecting the matters of his experience.
I should like you to consider that these functions (including passion, memory, and imagination) follow from the mere arrangement of the machine’s organs every bit as naturally as the movements of a clock or other automaton follow from the arrangement of its counter-weights and wheels.
Le Homme (The Treatise on Man) (1662)
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.
Letter to Marin Mersenne (1637)
Caustics are the brightest places in an optical field. They are the singularities of geometrical optics. The most familiar caustic is the rainbow, a grossly distorted image of the Sun in the form of a giant arc in the skyspace of directions, formed by the angular focusing of sunlight that has been twice refracted and once reflected in raindrops.
An optimist may see a light where there is none, but why must the pessimist always run to blow it out?
Misattributed