Let us drop down to verse 6. We are going to see here, and all the way through chapters 7, 8, 9, and most of chapter 10 the Bible is testifying of the Jews' wrong conception of Jesus Christ, specifically in chapter 7. It carries through the other chapters as well. The reason they have things misconceived is because the teaching that was in their mind, and by which they were going to be judged, was largely based upon tradition, not biblical fact.
This is in the third year of His preaching all over the area, and they are still asking questions about Him. Notice the way Jesus answered them.
They made no connection apparently between the Father and the Son.
Sometimes Jesus' apostles did not quite get the finer points of something, but they had really no problem with the teaching, especially when He said clearly what He meant. But this is the world we are talking about here.
That is why they were so confused. They were using their conception from their worldly tradition rather than from the word of God, and therefore they could not reach a right judgment about who He was and what He was doing.
Now wait a minute here! Are they inferring that Jesus never cracked the Bible? Are these people inferring that nobody ever taught Jesus? No. "Not having learned" means that He was not taught in their schools—their rabbinical schools. Jesus' teaching came directly from the Father.
"Never having learned"? No. It does not mean that Jesus never learned. It means that He did not go to the same school, the same rabbinical schools, that they did.
Oh, He was taught! He had the greatest and best teacher. He had the greatest and best and most important education anybody on earth in all of the history of mankind ever had, and it was already showing when He was twelve and one-half years old. No, He was not taught by men. He was taught by the Father. He did not need to be taught by men. He had the best teacher that there ever was.
So "not having learned" means that He was not taught at the rabbinical schools the way the other religious leaders were. He was not taught by men. He was taught by His Father.