As human beings how can we be so sure in anything?

Very philosophical. We can only truly know as fact what we can prove in a laboratory or through experimentation or through mathematical proof, but even that can be considered tenuous due to quantum uncertainty and our own (current) limitations.

Since all we have to go on right now is the universe in which we live, I believe we have a good grasp on things. I believe that someday humanity will achieve a level of knowledge that will allow it the powers that theists are currently assigning to a deity. We're just not there yet.

The default position is to assume a particular claim is nonexistent until sufficient evidence is presented to justify its possible existence. The claim of a supernatural creator has not met that quota in the scientific community, nor my standards.

This is the perfect example of the "epitome" of absurdity!

. . . Here's your quote: I know that no one knows anything at all.

You just made a knowledgeable truth claim. And you are also claiming that you know better than me.

I don't think those chemical reactions that are fizzing in your brain that evolved from stardust are working too well at all. Just sayin'.

I can answer this one pretty easily.

With regards specifically to this universe; setting aside the fact that it may be a matrix-like illusion, or a simulation, or whatever, the universe operates in a way that allows us to observe, measure, and test it consistently.

Would you like to know what that has yielded?

I'll give you a hint, you used a piece of it to type out this question.

It's called..... wait for it...

..wait for it..........

........

....technology.

Lol everyone has an opinion on something and somebody else has a different opinion on it

For me it is personal experience.