You just keep pushing. You just keep pushing. I made every mistake that could be made. But I just kept pushing.

At last I will devote myself sincerely and without reservation to the general demolition of my opinions.

Archimedes, that he might transport the entire globe ... demanded only a point that was firm and immovable; so also, I shall be entitled to entertain the highest expectations, if I am fortunate enough to discover only one thing that is certain and indubitable.

There is a great difference between mind and body insomuch as body is by nature always divisible, and the mind is entirely indivisible.

I suppose therefore that all things I see are illusions; I believe that nothing has ever existed of everything my lying memory tells me. I think I have no senses. I believe that body, shape, extension, motion, location are functions. What is there then that can be taken as true? Perhaps only this one thing, that nothing at all is certain.

And thereby make ourselves, as it were, the lords and masters of nature.

All is to be doubted.