Well, you either know a thing or not. Its really that simple. You know you are sitting at a table, typing, etc. I also accept the results of repeatable experiments, as long as I have verified them.
It really comes down to you. The individual. All ideas are therein. Are you prepared to kid yourself, or do you want the truth?
Often people say 'we' know to get around this. What does this usage of 'we' mean? It is trust that someone else has done the verifying, that they are trustworthy, that they are relaying the results faithfully, etc. If you are trusting though, you are not knowing.
Now, it is fine to have beliefs, and to accept other people's ideas and hypotheses. But it is another thing to say you know them to be true!
Marcuse and Gettier have some things to day about this (paraphrasing):
"The world is too complicated for people to verify everything themselves" -Marcuse
"Its not clear what (if anything) constitutes justified true belief" -Gettier
> I also accept the results of repeatable experiments, as long as I have verified them.
Per Quine, individual hypotheses can't be verified, only bundles of hypotheses.
Your epistemology leads you to not "know" all of science. Even logical positivism accepted the results of repeatable experiments, and logical positivism is itself too narrow of an epistemology (which is why it was rejected in the end).
I also profoundly mistrust any philosophy that says "the only way we know is X", where that rule (about the only way we know) is not something that is knowable via X. That leaves adherents using a rule (which by their own statements they do not know is valid) to decide what they do and do not know. That's... not something I can accept. It seems self-contradictory to me.
I'm not going to wade through your wall of questions. That's a much lower level of conversation than I am willing to get bogged down in.