It's struck me that reason (rationality, etc.) can be a tricky concept. I'm sure it could be said that it is irrational to be only rational (full rationality therefore being self-referentially unachievable - so the pressure is off!). But here I am saying that reason and rationality should be the guide - so I should think it through some more.
And I should have some working definitions for myself.
So, I guess what I mean by reason is in contrast to faith. I don't mean faith necessarily religiously here. By faith I mean a belief taken at face value - something that is believed true just because - because it sounds good, or feels good, or is what we'd want to be true. In contrast I take reason to be belief based on congruence with evidence and the whole of a logically consistent set of beliefs.
Setting up faith against reason always seems tricky, because at the base it seems that reason needs faith also - at least faith in the rules at the bottom taken to be irreducible. That sets up a question of whether premises are a form of faith, which I want to think about more for another time (I do think there's a difference).
In terms of the scope of reason, I think in the sphere of political philosophy there is only room for reason. Public policy that is based on what we might want to be true, or focusing on good intentions instead of results is unwise, possibly dangerous, and perhaps immoral.
In individual life, I think that it should be the underlying guide to living, but recognize that reason and rationality have their limits. Not only that, but the enjoyable parts of life are most likely the ones where rationality is put on a shelf. So I guess it seems wise to put up something like a framework based on reason, and filling in the rest as we see fit. Which I suppose comes down to a set of principles based on reason and just making sure we stick within that day-to-day.
At least I think that's what I'm trying to do.