It's only a problem in so far as your epistemology is justificatory. Otherwise, pragmatic – falsifiabilist – knowledge is not viciously circular or question-begging. For instance,

I know the Earth is round.

How do you know that?

By using geometry & comparing distant (north-south) noontime shadows like Eratosthanes had done.

How do you know that geometry is always correct? ...

... and so on and so on like Abbot & Costello's "Who's on first base?" circle-jerk.

But if, instead, I say

The Earth is round?

How do you know that?

Well, if the Earth is not round then it must either (1) be finite with an edge or (2) be infinite and flat such that traveling in any direction from this place I will not eventually return to this point. Agreed?

Sure, makes sense.

Good. So let's test them both at the same time by traveling in any direction from this place until we find the edge showing that I know 'the Earth is round' is false.

Um, okay ...

... so that by process of elimination the implications of a knowledge claim can be tested, never proving what we know but narrowing down from the universe of alternatives to a single best fit, unfalsified, claim which is still fallible (i.e. could be found to be false or less approximately true than some not yet proposed alternative claim).

At least, that's how I understand Peirce-Dewey, Popper & Haack's non-justificationist epistemology (re: fallibilism —> falsificationism & foundherentism, respectively).

Is there something that you feel or think you truly know. Perhaps some universal truth or intuitional feeling? What about something from experience? I would like to see your answers below. — Thinking

"Know" does not mean to be absolutely certain. It means to believe with adequate justification. By that standard I know lots of things. The sun will come up tomorrow. I love my children. All living organisms are the genetic descendants of an organism or organisms which lived more than a billion years ago. Cottage cheese is made with milk.

bravo! gold star to this guy.
perhaps in this paradox of yours there is freedom of will?

It's only a problem in so far as your epistemology is justificatory — 180 Proof

:up: It never struck me that that's a possibility. Non-justificationist epistemology! :chin: What I find intriguing is the definition of knowledge in such a system. The working definition of knowledge has justification as an essential feature, no?

You mentioned Karl Popper's falsifiability theory in relation to science. I'm not all that clear on that score though especially whether Popper's take on what counts as scientific knowledge is justificatory in nature or not. Do you mean to imply that science doesn't involve justification/argument of any kind? Preposterous! In case I've read you wrong, kindly explain yourself. G'day.

Sorry, I can't say it better or more succinctly than I have already. I mentioned four philosophers of the pragmatist-fallibilist school and provided a context with comparative examples. Miss the forest for the trees by taking terms out of context (I showed how I am using them in this discussion) at your leisure. Bottom line: "the criterion problem" is only a problem for a (classical) 'justificationist' approach to epistemology. (SEP & wiki are your friends, TMF.)

Sorry, I can't say it better or more succinctly than I have already. — 180 Proof

:up: No problemo, sir! You've been a big help. Muchas gracias, señor. Que tenga un buen día.

De nada. Y tu, mi amigo.

:lol: