Magnus Never beat me so how do we know he is better than me?

If that is the case, a newbie who has played at least one chess game and won the game(s) (though on time) can proclaim that he/she is better than Carlsen because "he/she has not lost a single game before" whereas Carlsen has lost hundreds of games before, if not thousands.

Checks out, Congratulations on being better than Magnus !

lucky guess ?

How do we know that you are a better player than a chimpanzee? Have you ever beaten one?

lol

you saying that

lol

Could it be you are not good enough

"Magnus Never beat me so how do we know he is better than me?"

Because the odds favor him based on historical experience.

He may not be "better" than you just better at chess than you.

And only based on the  accepted rules he plays by. 

i agree

"Magnus Never beat me so how do we know he is better than me?"

Hmm, educated guess, intuition, common sense, rating differential, reputation . . .

Hi stranger, nice to see you scrolling down here

who R u calling stranger

hope it's not me

Because Magnus played 20 games a day - he wins them all
But if you play 20 games a day - you won't win them all ...
So you see he's better than you ...

It's called anecdotal evidence.  He's beaten a large number of strong players.  The probability of your being in the top 1% is zilch.  Hence, he is better than you.