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René Descartes quotes on certainty

2 verified English passages where René Descartes’ thought meets questions of certainty.

René Descartes on certainty

René Descartes (1596–1650) approaches certainty within Rationalism. The cogito identifies thinking as indubitable; he distinguished thinking substance from extended substance and defended clear and distinct ideas. Systematically, the teaching links method, mind, mathematics into a practical and theoretical whole. On this page, the archive isolates English passages where that project meets certainty most directly—useful for searches such as “rené descartes quotes on certainty.”

How to use this page

Start with the shortest passage, then compare tone across sources. Return to the René Descartes thinker page for biography and to the certainty theme for other voices on the same question.

Frequently asked

What did René Descartes say about certainty?

The quotations below are the archive’s curated answer: English renderings selected for clarity and attribution, not a complete corpus.

Where else should I read after rené descartes on certainty?

Related themes: Philosophy , Self , Knowledge , Freedom , Life , Wisdom .

  1. I think, therefore I am.
    Q0054
    Principles of Philosophy (Latin)
  2. I am, I exist—whenever it is uttered by me, or conceived in the mind, it is necessarily true.