Yudkowsky says:

So if you understand what concept we are generally getting at with this word "rationality", and with the sub-terms "epistemic rationality" and "instrumental rationality", we have communicated: we have accomplished everything there is to accomplish by talking about how to define "rationality". What's left to discuss is not what meaning to attach to the syllables "ra-tio-na-li-ty"; what's left to discuss is what is a good way to think.

With that said, you should be aware that many of us will regard as controversial - at the very least - any construal of "rationality" that makes it non-normative:

For example, if you say, "The rational belief is X, but the true belief is Y" then you are probably using the word "rational" in a way that means something other than what most of us have in mind. (E.g. some of us expect "rationality" to be consistent under reflection - "rationally" looking at the evidence, and "rationally" considering how your mind processes the evidence, shouldn't lead to two different conclusions.) Similarly, if you find yourself saying "The rational thing to do is X, but the right thing to do is Y" then you are almost certainly using one of the words "rational" or "right" in a way that a huge chunk of readers won't agree with.

A normative belief in rationality is, as far as I can tell, not possible for someone who does not have a clear concpetion of what rationality is. I am trying to present tools for forming such a conception. The theory I am presenting is, most accurately, a rationally constructed language, not a prescriptive theory on whether it is moral to be rational. The merit of this language is that it should allow you to converse about rationality with mysticists or religious people so that you both understand what you are talking about. It seems to me the ID vs. evolution debate remains unresolved among the general public (in the USA) because neither side has managed to speak the same language as the other side. My language is not formally defined in the sense of being a formal language, but it has formally defined ontological types.