I think, therefore I am

Why it stays with me

Descartes set out to doubt everything that could possibly be doubted, including his senses and even whether the world existed. He found that one thing survived: the fact that he was doubting meant he was thinking, and so he must exist.

The Grand Design also credits Descartes with an early modern idea of laws of nature, rules that apply everywhere and always. He was a scientist as well as a philosopher, which was normal then.

The method interests me more than the conclusion. Starting from doubt, looking for what can’t be shaken, and building from there is still a good way to test any belief.