The French philosopher René Descartes (1596-1650) was equally well known for mathematics and science as well as philosophy. He is perhaps most famous for his saying, “I think, therefore I am” (in Latin, “Cogito ergo sum”).

    The son of a politician, he lost his mother when he was only 1, and was raised by his grandmother and great-uncle. A sickly boy, he started school late, but was soon exposed to the ideas of Galileo. By age 20, he had graduated with degrees in law.

    After moving to Paris, he wrote, “I entirely abandoned the study of letters. Resolving to seek no knowledge other than that which could be found in myself or else in the great book of the world, I spent the rest of my youth traveling... gathering various experiences... [and] reflecting upon whatever came my way so as to derive some profit from it.”

    It may have been this habit of experiencing and thinking deeply which led to the three “visions” he had on the night of Nov. 10, 1619. From these came his great philosophical insight.

    The idea goes like this: As most of us know, our senses sometimes deceive us. How, then, can we know that anything is true? In fact, this radical doubt could even lead us to doubt our own existence! But, as Descartes realized, if someone doubts his own existence, someone must be doing the doubting. As he wrote, “We cannot doubt of our existence while we doubt ...”

    From this certainty — that the thinker exists — he was then able to re-establish the existence of the world as we perceive it.

    Simple as it may seem, this idea confirmed the basis of what is called “rationalism,” the idea that we can obtain knowledge through the use of reason. In contrast is “empiricism,” the idea that knowledge can come only from sense experience. Descartes was not opposed to this idea, either. These two — rationalism and empiricism — are both essential in the development of the scientific method.

    After becoming tutor to Queen Christina of Sweden, Descartes caught a cold which developed into a respiratory infection, and he died at 53. First buried in Stockholm, his remains were later returned to France.

    Vocabulary

    Which word above means:

    1. trick, cause (someone) to believe something not true

    2. a kind of disease involving germs

    3. impressive; formidable

    4. set up again

    5. deep, fundamental, basic

    6. of the lungs or breathing

    7. see, hear, smell, etc.

    8. left alone, gave up on

    9. thinking (about)