... The Western philosophical tradition provides a venerable partial answer to the question of who we are: What characterizes the essence of who we are is a locus of consciousness and rationality ...
[I already read this:] First, to know whether to use "who" or "whom," we need to talk about the difference between subjects and objects because you use "who" when you are referring to the subject of a clause and "whom" when you are referring to the object of a clause.
My guess: we is the subject. In this relative clause, the speaker represents we as another OBJECT. Since OBJECTS require 'whom', whom we are is right, and who we are is wrong.
Yet my guess jars with the following. So am I wrong?
[User 'RuthP' dated 2012 Dec 26:]
That is a(n incorrect) hyper-correctness, to which many people are prey. No, because the only verb you have is to be (are, in this case). To be cannot take an object, because it is an identity, so in your sentences, who and we are the same. Since we is the subject, so is who.
If apt, please see user 'leonAzul' 's comment, dated 2012 Dec 26 (also in this same thread).