You should believe facts. You should believe logical inference from facts.
You should believe arguments insofar as they corroborate or refute facts.
And, if an argument can't be tested, it's not a very good argument.
Thankfully not. A "fact" is something that can be measured in such a way that even if you are totally antagonistic to my arguments, we will get the same result.
Now your "argument" may attempt to prove the irrelevancy or inadequacy of my facts, but the facts themselves should be unfudgeable.
If you try to replicate a fact, you'll succeed If you try to disprove a fact, you'll fail If you find rebuttles to a fact, they'll be hollow
The only thing in the obvious list that doesn't separate a fact from a non-fact is the arguments in support. Hence why scientists are taught not to care for arguments in support, only research, and then specifically arguments that disprove more than those that prove.