This is my fifth post for Joe Carter's collaborative project Jesus the Logician (which would better be described as Jesus's Reasoning).
In Mark 11:27-33 (also related in Matthew 21:23-27 and Luke 20:1-8), Jesus is questioned by the Pharisees, and he seems to ignore their question entirely. What's buried behind his silence is an argument against their authority even to ask the question.
And they came again to Jerusalem. And as he was walking in the temple, the chief priests and the scribes and the elders came to him, and they said to him, "By what authority are you doing these things, or who gave you this authority to do them?" Jesus said to them, "I will ask you one question; answer me, and I will tell you by what authority I do these things. Was the baptism of John from heaven or from man? Answer me." And they discussed it with one another, saying, "If we say, 'From heaven,' he will say, 'Why then did you not believe him?' But shall we say, 'From man'?� � they were afraid of the people, for they all held that John really was a prophet. So they answered Jesus, "We do not know." And Jesus said to them, "Neither will I tell you by what authority I do these things." (Mark 11:27-33, ESV)
The chief priests, scribes, and elders are challenging Jesus' authority, asking him to testify in their court of law as to what gives him the authority to do what he's been doing. He could have simply said that his authority comes from God. In other instances, he did as much. What he does in this instance is fairly interesting. He turns their challenge on its head. He asks them where John the Baptist's authority came from. They won't answer the question, because admitting to John's authority from God would mean that the one he explicitly said his ministry was pointing toward must be from God. They can't say what they believe, however, because the people would be mad due to John's popularity. Thus Jesus silences them.
Now this looks like a mere rhetorical trick. I won't answer you unless you answer me first. That's no argument. I think it's a mistake to see it that way, though. What Jesus has done is itself an argument. They've asked him a question, challenging his authority and seeking for him to show that he's from God. He, of course, has already done so through his actions. They don't accept that evidence. That's the real issue here. His question about God brings that forth. The evidence is all out there regarding John. They know what he did. They know what he said. Yet they won't bring themselves to comment on that evidence, the sort of thing a genuine authority should be able to do. They won't allow their own courtroom to evaluate the evidence regarding John. This is despite their obvious opinion that he was not from God. Why should Jesus testify in their courtroom if they're so incompetent as to be unable to evaluate evidence in a reasonable manner and admit their conclusions in the same courtroom?
He has thus identified an inconsistency between their portrayal of their purpose and their actual methods. The argument is against them. He still hasn't answered their question, but he's shown that they have no right to expect an answer from him until they can perform the job required of those who can ask such questions.