Do you know anything?

I know this sounds provocative, but there is depth to the question.
After discussing about atheists it appears that many people think that, 1) there is no proof that a deity exists 2) Science has disproven the existence of a deity.
What is proof?

People have different definitions of reality. People use different methods to determine reality.

What is absolute unquestionable reality?

This question is intended to reach the very core of your thinking process. How do you know that you know anything?

I split my thinking process into three levels, knowledge, assumption and belief.

Knowledge is absolute.

Assumptions are what you accept as reality even though there are doubts.

Beliefs are when you have little proof but you accept the concept as true.

Both assumptions and beliefs have many sublevels.

You could assume that while crossing the road you won’t get hit by a car, but it could happen. You assume that by getting a job your finances will be taken care of, but you could get fired.

You can believe that aliens occasionally invade earth but there is little evidence if any that they did.

My method is to put each concept in its proper category. If it is an assumption or belief I intellectually weigh it and see how close it is to absolute reality.

So, is there anything that people absolutely know? If yes, what? If no, what is the basis of weighing assumptions?