"No one is good except God alone"

I’ve been thinking about the logic of Jesus’ exchange with the rich young ruler (Luke 18, Matt 19, and Mk 10).

And a ruler asked him, “Good Teacher, what must I do to inherit eternal life?” And Jesus said to him, “Why do you call me good? No one is good except God alone.” (Luke 18:18–19)

Now, upon a superficial reading, Jesus might seem here to be implicitly denying his divinity. However, Jesus is doing exactly the opposite: in a very much Socratic fashion, Jesus is implicitly—and quite cleverly—affirming his divinity. When Jesus asks the ruler, “Why do you call me good?” he could be implying one of two things, which would have been easily conveyed in Jesus’ voice inflection and body language. Either Jesus was implying that the ruler was incorrect in his observation that Jesus was good, or he was implying that the ruler was correct.

A superficial and faulty reading might proceed thus:

1) Jesus says that only God is good.
2) Jesus does not think he is God (and/or is not God).
3) Therefore, Jesus is saying that he is not good.
4) Therefore, Jesus is implicitly saying that he is not God.

The problem with this reading is (2). Jesus does not say that he is not God, and to say such would be an unnecessary assumption foreign to the text. A better and more natural reading proceeds as follows:

5) Jesus says that only God is good.
6) Jesus does not deny that he is good, as the ruler says.
7) Therefore, Jesus is saying, in a clear but indirect and Socratic way, that he is God.

This would seem to basically amount to the following modus ponens argument:

8) Only God is good.
9) Jesus is good.
10) Therefore, Jesus is God.

In fact, Jesus is speaking in this way to try to make the ruler stop and consider what it might have meant to call Jesus good. Reading between the lines, we can hear Jesus saying to the ruler, “Truly, you speak more than you know.”

Although I shall not discuss it now, it might be worth considering the parallel accounts of this episode in Matt 19:16ff and Mark 10:17ff (Matthew’s account is worded slightly differently than the others'). Also, what exactly might “good” mean?