While I don't think that we can reason everything from first principles, those who think they can are doomed to fall pray to their own personal bias and repeat errors that our forebearer had, I do think that everyone should give everything a bit of a quick sanity check before accepting anything as a new belief.

Just a small, quick, bit of review. Does this thing make logical sense? Does it smell of any logical fallacies? What are the priors, or assumptions, that the argument is making?

I am not a fan of Scott Alexander, but he does at least give a fair amount of thought to his arguments and conclusions. However that doesn't mean much if the premise is flawed or his priors are miss calibrated. This goes for anyone. Just because the person you're looking up to has well reasoned arguments doesn't mean they're correct.

Aquinas started from the position that god exists and went from there. And while his arguments are really well reasoned and logical, they only make sense if you accept his priors.

Any given argument makes sense if your priors start in the right place for them. Euclidian Geometry works great, but if you throw out/modify the parallel postulate you can get wildly different answers for what makes sense. You can craft crazy mathematical worlds if you tweak ZFC, throw away the axiom of choice and some different stuff starts to happen.

Anyways, I hope you stop glazing scott, take everything you read with a grain of salt, and think for yourself.