Rene Descartes

Give me matter and motion, and I will construct the universe.

The mind is a substance whose whole essence or nature is to think, and which needs no place, nor depends on any material thing, in order to exist.

All that is needed to arrive at the truth is good sense, which is naturally equal in all men.

I have long ago observed that in order to study the truth, it is necessary once in the course of our life to demolish everything completely and start again from the foundations.

I shall proceed by setting aside all that in which I can suppose there to be the slightest doubt, just as if I had discovered that it was wholly false.

I desire to live, and to continue the studies I have begun, but I have not found anyone who could tell me where to go.

I always wanted to learn to distinguish the true from the false, in order to see clearly in my actions and to walk with confidence in this life.

The greatest good is to live according to the dictates of right reason.

To be a good philosopher, one must be a good mathematician.

My purpose is not to teach a method which everyone ought to follow to guide his reason, but only to show how I have tried to guide mine.

I have never found anything in the works of the ancient philosophers that compares to the certainty I have found in mathematics.

The light of natural reason is sufficient to distinguish the true from the false.

I concluded that I was a substance whose whole essence or nature consists only in thinking, and that, in order to exist, it needs no place and depends on no material thing.

My entire life has been directed toward the acquisition of knowledge.

I know that I am a thinking thing, and that I have an idea of God.

The greatest good is the knowledge of truth.

I found myself constrained to believe that there are certain principles which the human mind spontaneously accepts as true.

I have never made any discoveries that were not based on the certainty of mathematics.

The body is a machine.

I was very surprised to find that I had been mistaken more often than not in my life.