So understanding the subject matter makes one an authority. I see. What if his understanding is full, but also very wrong? For example, he can say, "I know that the bible says..." but then draw all the wrong conclusions too.
In general terms, that's right. I don't know where you've been for the last few years -- but unless you haven't noticed -- there are lots of "authorities" (and recognized ones) who disagree with each other. Thus the diagreement with each other doesn't make them be "considered" any less of an authority -- even though they can be saying totally opposite things to each other.
I have to laugh at this "splitting hairs" by you (in terms of the word "authority") because anyone and their dog knows that if one were to go into a court case and call in so-called "authorities" you could practically buy any authority you wanted for any viewpoint. Thus, what you say is totally irrelevant in terms of describing the word (and term) authority.
But, having said that -- there is definitely a concern for the truth -- no matter if one is an authority or not. And I think I answered that issue (i.e., the one about "truth") in post #62. That pretty much covers the issue.
Let me also say that the "authority of the inspired word of God" is not what we're talking about here. The question was simply "What makes him an authority?"
No person is "inspired of God" today, since the cannon of Scripture is closed. Thus, the authority that resides in Scripture (which is full and complete) is not what we're talking about here in terms of "What makes a person an authority?" That's a pretty general question and gets a pretty general answer.
My general answer stands.
Perhaps -- on the other hand -- maybe what one was really asking is how we can tell a wrong interpretation of Scripture from a right one? If that's it, then it gets a different answer (which I did not address, there).