From having watched a lot of Joe's podcasts, when he disagrees he likes to question and argue. It's not necessarily bad, I think they weren't necessarily explaining themselves perfectly well. Firas had to change his analogies a few times to make himself clearer.Joe seemed angry that Firas spoke about philosophy, I've never seen him so close minded. Anyways , analytical philosophy does that to me too.
To me, arguing about what makes the letter "A" actually the letter "A" is a bit of pointless discussion.
I think Joe didn't agree about how Science isn't concrete, so they wasted time on this because Firas didn't explain it too well. Essentially, Firas was only saying that science is forever evolving and changing, therefore you cannot call what you know today as an absolute truth, and so it is an hypothesis.
Felt like they were arguing over semantics a bit.