- I know that I doubt because if I doubt that I doubt, I am still doubting
- I doubt, therefore I think
- I think therefore I am
I'm an agnostic. I can't actually disagree with any of the above based on logic as I understand it. But then perhaps my understanding of logic is flawed. Descartes then rambled on for a bit about how the presence of a mind that can think proves the existence of God, at which point he lost me in rhetoric and religious nonsense based on socialised opinions in my view, but the three points above appear, to me, to stand up to scientific analysis.
Something must be true. If not, the statement "Nothing is true" would be true, therefore false, therefore true etc ad infinitum.
There is something more complex than we understand going on here than we realise. The above simply proves it. To claim that you know what it is is largely puerile and boring as far as I am concerned.