I’ll say again what my reasoning is.
OK.
At the beginning of the first century, in the areas where Jesus and the apostles were teaching, the lowest estimate that I’ve seen for literacy is 3%.
OK. I would happily go higher.
"And he (Jesus) came to Nazareth where he had been brought up and, as he was accustomed to do, he entered the synagogue on the day of the Sabbath and stood up to read. And a scroll of the prophet Isaiah was handed to him ... " (Luke 4:16-17)
So Jesus could read Hebrew sufficiently to read from the Scriptures. Does this mean everyone could? Well, men only, obviously. But this is after Jesus' sojourn with the Baptist, and on His return to Capernaum after his testing in the wilderness. We've had hints that before, Jesus displayed an audacious intelligence: "And it happened that, after three days, they found him in the Temple, sitting amid the teachers, both listening to them and posing them questions; and those listening to him were astonished at his intelligence" (Luke 2:46-47) and this when He was 12 years old!
So I would suggest the sons of the (ahem) better families were taught at the synagogue school, to read and write, their numbers, etc., and of course Scripture reading would have been central to that. So we can dare to suggest that Jesus read Hebrew, spoke Aramaic ... and just to muddy the waters, exegetes point out that both Paul and the Gospels seem to use the Greek LXX as their Scripture reference! So three languages in the mix.
Turning to the disciples, then Matthew was a tax collector so he'd have to know how to read and write. If "James the brother of Jesus" was not a complete brat, or from a dysfunctional family, he probably went to synagogue school, too.
Fishermen they might have been, but James and John were the sons of a successful fleet owner. Peter was probably successful as well. So I'd put them among the Middle Classes (to use the English system), certainly at the top end of Working Class. They weren't illiterate peasants.
The Jerusalem elite listened to Peter and John preaching in the Temple, "And, seeing the audacity of Peter and John, and perceiving them to be unlettered and common men, they were amazed, and recognized them as having accompanied Jesus" (Acts 4:13) – the term is
agrammatoi, 'uneducated', but this doesn't mean illiterate, rather that they showed no sign of a formal exegetical training. That was the realm of the
grammataeus, the 'scribe' (as in 'scribes and pharisees')
Galilee was a cultural mix, as well, I believe. Four of the twelve, Philip, Andrew, Thaddeus and Bartholomew, had Greek names, so we can see a mix of culture and influence here.
Going back to scribes – this was an important profession in the Ancient World. Allowing that at least some of the disciples were sufficiently literate to manage their own affairs, they would have engaged scribes to draft documents.
Paul used scribes. One of them even slipped in his own name in the Letter to the Romans: "Timothy, my fellow laborer, greets you, as do Lucius and Jason and my kinsman Sosipater. (I, Tertius, who am writing out this letter in the Lord, greet you.)" (Romans 16:21-22).
So did Peter: "I wrote to you briefly through Silvanus... " (1 Peter 5:12)
Also, it was part of the culture for disciples of master teachers to write notes about what their masters were teaching. Those would include lists of sayings and descriptions of activities.
OK – Paul studied under Gamaliel the Elder in Jerusalem. There were philosophical schools in Athens, Alexandria and elsewhere – but one can't assume a correspondence between them and an itinerant preacher in Galilee-Judea. You have to admit it's a bit of a leap?
There were forms of writing that anyone could use, and materials for them available everywhere.
Were there?
None of the criticism of those books denies anything that I’m saying, and most of the criticism confirms it.
I don't necessarily deny the book references, I'm just suggesting that there might not be any evidence that what's in those books refers to the
particular situation we're talking about.
... It means mostly oral with some written “memory aids,” which is a euphemism for reproductions of notes written by disciples during the times that Jesus and the apostles were teaching.
Is it, or is that how you choose to interpret it?