I see at least two basic ways that one could approach the issue.
The first is to treat it like a mindhack, and evaluate it by its apparent results in people who have applied it. Ask them what good it’s done them, and observe their lives and behavior to confirm. Perhaps tell them what your idea of “useful” is and ask them to constrain their explanation of what it’s done to those things.
The second is to examine whether it leads to testable beliefs that turn out to be accurate (cf. this comment). See if there is a topic which enlightenment is claimed to be relevant to which you consider useful, state some beliefs, see if the enlightened person says otherwise, and go from there. (This requires that the enlightened person also be rational and well-informed. An enlightened person who doesn’t know anything about the subject you want to talk about, who is uneducated, mentally ill, brain-damaged, or whatever, is probably not going to state accurate beliefs, for reasons unrelated to enlightenment.)
I see at least two basic ways that one could approach the issue.
The first is to treat it like a mindhack, and evaluate it by its apparent results in people who have applied it. Ask them what good it’s done them, and observe their lives and behavior to confirm. Perhaps tell them what your idea of “useful” is and ask them to constrain their explanation of what it’s done to those things.
The second is to examine whether it leads to testable beliefs that turn out to be accurate (cf. this comment). See if there is a topic which enlightenment is claimed to be relevant to which you consider useful, state some beliefs, see if the enlightened person says otherwise, and go from there. (This requires that the enlightened person also be rational and well-informed. An enlightened person who doesn’t know anything about the subject you want to talk about, who is uneducated, mentally ill, brain-damaged, or whatever, is probably not going to state accurate beliefs, for reasons unrelated to enlightenment.)