Rene Descartes (March 31, 1596 – February 11, 1650), also known as Renatus Cartesius (Latinized form),[2] was a French philosopher, mathematician, physicist, and writer who spent most of his adult life in the Dutch Republic. He has been dubbed the “Father of Modern Philosophy”, and much of subsequent Western philosophy is a response to his writings, which continue to be studied closely to this day. In particular, his Meditations on First Philosophy continues to be a standard text at most university philosophy departments. Descartes’ influence in mathematics is also apparent, the Cartesian coordinate system—allowing geometric shapes to be expressed in algebraic equations—being named for him. He is credited as the father of analytical geometry. Descartes was also one of the key figures in the Scientific Revolution. Descartes founded analytic geometry, the bridge between algebra and geometry, crucial to the discovery of infinitesimal calculus and analysis. He is best known for the philosophical statement “Cogito ergo sum” (French: Je pense, donc je suis; English: I think, therefore I am; or I am thinking, therefore I exist), found in part IV of Discourse on the Method (1637 – written in French but with inclusion of “Cogito ergo sum”) and §7 of part I of Principles of Philosophy (1644 – written in Latin).

Cogito ergo sum. (I think; therefore I am.)
Rene Descartes

In order to improve the mind, we ought less to learn, than to contemplate.
Rene Descartes

Except our own thoughts, there is nothing absolutely in our power.
Rene Descartes

It is not enough to have a good mind; the main thing is to use it well.
Rene Descartes

An optimist may see a light where there is none, but why must the pessimist always run to blow it out?
Rene Descartes

It is easy to hate and it is difficult to love. This is how the whole scheme of things works. All good things are difficult to achieve; and bad things are very easy to get.
Rene Descartes

I am accustomed to sleep and in my dreams to imagine the same things that lunatics imagine when awake.
Rene Descartes

A state is better governed which has few laws, and those laws strictly observed.
Rene Descartes

Common sense is the most fairly distributed thing in the world, for each one thinks he is so well-endowed with it that even those who are hardest to satisfy in all other matters are not in the habit of desiring more of it than they already have.
Rene Descartes

Divide each difficulty into as many parts as is feasible and necessary to resolve it.
Rene Descartes

Each problem that I solved became a rule, which served afterwards to solve other problems.
Rene Descartes

Everything is self-evident.
Rene Descartes

I am indeed amazed when I consider how weak my mind is and how prone to error.
Rene Descartes

I hope that posterity will judge me kindly, not only as to the things which I have explained, but also to those which I have intentionally omitted so as to leave to others the pleasure of discovery.
Rene Descartes

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.
Rene Descartes

Illusory joy is often worth more than genuine sorrow.
Rene Descartes

In order to improve the mind, we ought less to learn, than to contemplate.
Rene Descartes

It is not enough to have a good mind; the main thing is to use it well.
Rene Descartes

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

One cannot conceive anything so strange and so implausible that it has not already been said by one philosopher or another.
Rene Descartes

Perfect numbers, like perfect men, are very rare.
Rene Descartes

The first precept was never to accept a thing as true until I knew it as such without a single doubt.
Rene Descartes

The greatest minds are capable of the greatest vices as well as of the greatest virtues.
Rene Descartes

The reading of all good books is like a conversation with the finest minds of past centuries.
Rene Descartes

The senses deceive from time to time, and it is prudent never to trust wholly those who have deceived us even once.
Rene Descartes

The two operations of our understanding, intuition and deduction, on which alone we have said we must rely in the acquisition of knowledge.
Rene Descartes

There is nothing so strange and so unbelievable that it has not been said by one philosopher or another.
Rene Descartes

Travelling is almost like talking with those of other centuries.
Rene Descartes

When it is not in our power to follow what is true, we ought to follow what is most probable.
Rene Descartes

Whenever anyone has offended me, I try to raise my soul so high that the offense cannot reach it.
Rene Descartes

You just keep pushing. You just keep pushing. I made every mistake that could be made. But I just kept pushing.
Rene Descartes