What was rene descartes famous quote

I made every mistake that could be made. But I just kept pushing. I realized that it was necessary, once in the course of my life, to demolish everything completely and start again right from the foundations if I wanted to establish anything at all in the sciences that was stable and likely to last. The main thing is to use it well. A thing that thinks. What is that? A thing that doubts, understand, affirms, denies, wills, refuses, and that also imagines and senses.

But from time to time I have found that the senses deceive, and it is prudent never to trust completely those who have deceived us even once. The greatest minds, as they are capable of the highest excellence, are open likewise to the greatest aberrations; and those who travel very slowly may yet make far greater progress, provided they keep always to the straight road than those who, while they run, forsake it.

I look for aid to the imagination. I am supposing all these things to be nothing. For whereas reason is a universal instrument that can be used in all kinds of situations, these organs need a specific disposition for every particular action.

Clarke, Penguin edition , Part 5, The World and Other Writings , trans. Stephen Gaukroger , I was then in Germany, where I had been drafted because of the wars that are still going on there, and as I was returning to the army from the emperor's coronation, the arrival of winter delayed me in quarters where, finding no company to distract me and, luckily, having no cares or passions to trouble me, I used to spend the whole day alone in a room, that was heated by a stove, where I had plenty of time to concentrate on my own thoughts.

As translated by John Cottingham, et al. If I had been taught from my youth all the truths of which I have since sought out demonstrations, and had thus learned them without labour, I should never, perhaps, have known any beyond these; at least, I should never have acquired the habit and the facility which I think I possess in always discovering new truths in proportion as I give myself to the search.

In English from John Veitch trans. If there is any work in the world which cannot be so well finished by another as by him who has commenced it, it is that at which I labour.

If we had a thorough knowledge of all the parts of the seed of any animal e. In order to seek truth, it is necessary once in the course of our life, to doubt, as far as possible, of all things. It is not enough to have a good mind. The main thing is to use it well. It is well to know something of the manners of various peoples, in order more sanely to judge our own, and that we do not think that everything against our modes is ridiculous, and against reason, as those who have seen nothing are accustomed to think.

It must not be thought that it is ever possible to reach the interior earth by any perseverance in mining: both because the exterior earth is too thick, in comparison with human strength; and especially because of the intermediate waters, which would gush forth with greater impetus, the deeper the place in which their veins were first opened; and which would drown all miners.

Let us now declare the means whereby our understanding can rise to knowledge without fear of error. There are two such means: intuition and deduction. By intuition I mean not the varying testimony of the senses, nor the deductive judgment of imagination naturally extravagant, but the conception of an attentive mind so distinct and so clear that no doubt remains to it with regard to that which it comprehends; or, what amounts to the same thing, the self-evidencing conception of a sound and attentive mind, a conception which springs from the light of reason alone, and is more certain, because more simple, than deduction itself.

It may perhaps be asked why to intuition we add this other mode of knowing, by deduction, that is to say, the process which, from something of which we have certain knowledge, draws consequences which necessarily follow therefrom. But we are obliged to admit this second step; for there are a great many things which, without being evident of themselves, nevertheless bear the marks of certainty if only they are deduced from true and incontestable principles by a continuous and uninterrupted movement of thought, with distinct intuition of each thing; just as we know that the last link of a long chain holds to the first, although we can not take in with one glance of the eye the intermediate links, provided that, after having run over them in succession, we can recall them all, each as being joined to its fellows, from the first up to the last.

Many small strikes of a hammer will finally have as much effect as one very heavy blow. The nature of matter, or body considered in general, consists not in its being something which is hard or heavy or coloured, or which affects the senses in any way, but simply in its being something which is extended in length, breadth and depth. The seeker after truth must, once in the course of his life, doubt everything, as far as is possible. This will not seem strange to those who know how many different automata or moving machines can be devised by human ingenuity, by using only very few pieces in comparison with the larger number of bones, muscles, nerves, arteries, veins and all the other parts in the body of every animal.

They will think of this body like a machine which, having been made by the hand of God, is incomparably better structured than any machine that could be invented by human beings, and contains many more admirable movements. Science quotes on: Divisible 5 Infinity 92 Part Quantity We cannot doubt of our existence while we doubt, and that this is the first knowledge we acquire when we philosophize in order.

The knowledge, I think, therefore I am , is the first and most certain that occurs to one who philosophizes orderly. When first I applied my mind to Mathematics I read straight away most of what is usually given by the mathematical writers, and I paid special attention to Arithmetic and Geometry because they were said to be the simplest and so to speak the way to all the rest.

But in neither case did I then meet with authors who fully satisfied me. I did indeed learn in their works many propositions about numbers which I found on calculation to be true. As to figures, they in a sense exhibited to my eyes a great number of truths and drew conclusions from certain consequences. But they did not seem to make it sufficiently plain to the mind itself why these things are so, and how they discovered them.

Consequently I was not surprised that many people, even of talent and scholarship, should, after glancing at these sciences, have either given them up as being empty and childish or, taking them to be very difficult and intricate, been deterred at the very outset from learning them. In Elizabeth S. Haldane trans. Ross trans.

When it is not in our power to determine what is true, we ought to act according to what is most probable. This is clear from the fact that if he were deducing it by means of a syllogism, he would have to have had previous knowledge of the major premiss 'Everything which thinks is, or exists'; yet in fact he learns it from experiencing in his own case that it is impossible that he should think without existing.

It is in the nature of our mind to construct general propositions on the basis of our knowledge of particular ones. Cottingham, R. Stoothoff and D. Murdoch, Vol. But as I considered the matter carefully it gradually came to light that all those matters only were referred to Mathematics in which order and measurements are investigated, and that it makes no difference whether it be in numbers, figures, stars, sounds or any other object that the question of measurement arises.

I saw consequently that there must be some general science to explain that element as a whole which gives rise to problems about order and measurement, restricted as these are to no special subject matter. Rules for the Direction of the Mind written Appears without citation in Howard W.

Webmaster regards this as an orphan better regarded as anonymous , and has so far been unable to trace a primary source in the work of Descartes. Quoted, without citation, in George F. Simmons, Calculus Gems , , It is a bad sign that other quotes on the same page do have sources footnoted, but not for this subject quote.

So, Webmaster regards the quote as an orphan better attributed to anonymous having so far being unable to locate a primary source. Science quotes on: Clear Transcendental 10 Write Writing Descartes' immortal conclusion cogito ergo sum was recently subjected to destruction testing by a group of graduate researchers at Princeton led by Professors Montjuic and Lauterbrunnen, and now reads, in the Shorter Harvard Orthodoxy : a I think, therefore I am; or b Perhaps I thought, therefore I was; but c These days, I tend to leave that side of things to my wife.

Follow Descartes! Do not give up the religion of your youth until you get a better one. The stone that Dr. Johnson once kicked to demonstrate the reality of matter has become dissipated in a diffuse distribution of mathematical probabilities.

The ladder that Descartes, Galileo, Newton, and Leibniz erected in order to scale the heavens rests upon a continually shifting, unstable foundation. Break the chains of your prejudices and take up the torch of experience, and you will honour nature in the way she deserves, instead of drawing derogatory conclusions from the ignorance in which she has left you. Simply open your eyes and ignore what you cannot understand, and you will see that a labourer whose mind and knowledge extend no further than the edges of his furrow is no different essentially from the greatest genius, as would have been proved by dissecting the brains of Descartes and Newton; you will be convinced that the imbecile or the idiot are animals in human form, in the same way as the clever ape is a little man in another form; and that, since everything depends absolutely on differences in organisation, a well-constructed animal who has learnt astronomy can predict an eclipse, as he can predict recovery or death when his genius and good eyesight have benefited from some time at the school of Hippocrates and at patients' bedsides.

Machine Man , in Ann Thomson ed. Laplace would have found it child's-play to fix a ratio of progression in mathematical science between Descartes, Leibnitz, Newton and himself. Illumination Light Soul. Aristotle Philosopher.

Baruch Spinoza Philosopher. Blaise Pascal Mathematician. David Hume Philosopher. Francis Bacon Former Lord Chancellor. Friedrich Nietzsche Philologist. Galileo Galilei Physicist. Georg Wilhelm Friedrich Hegel Philosopher. Gottfried Leibniz Mathematician.

Immanuel Kant Philosopher. Isaac Newton Physicist. Jean-Jacques Rousseau Philosopher. Johannes Kepler Mathematician. John Locke Philosopher. Nicolaus Copernicus Mathematician. Plato Philosopher.