Name 1 Something that You are Sure of

[Whateverist]

Did you have in mind something like Descartes' foundational thought, I think therefore I am? In all seriousness I would dismiss that whole enterprise. The part of our brain that does logic and language is so new that to make the rest of our experience answerable to that part would just be odd. It is logic which should serve feeling and the rest of our wide range of experiences, not the other way around. Logic should be a servant, not the captain.