Classification systems using terminology or a symbolic system that is not intuitive form the basis of scientific “knowledge.” In this system, particularly unusual phenomena are slotted into established patterns. Then, when features that do not fit present themselves, scholars treat them in different ways: (1) scrubbing the anomalous data as individual peculiarity, or as contaminated by some outside influence; (2) engaging in fine-tuning the classification system by subdividing or changing categories or by refining the mathematical analysis; or (3) declaring the entire approach invalid. As scholars have worked to incorporate a growing corpus of Gnostic texts from third- and fourth-century Coptic codices into patristic accounts of Gnostic sects, older heresiological categories do not fit. Some scholars call for dropping the terms “Gnostic” and “Gnosticism,” but the preferred approach remains fine-tuning or revising categories.1 A common variant of “scrubbing data” in this field organizes divergent material from a text into editorial layers added to an original core.

Critical study of the Gospels has sought the human Jesus behind the mythic and theological symbols of Christianity. Analysis of material common to Matthew, Mark and Luke and of sayings common to Matthew and Luke (designated 'Q', German Quelle, 'source') has provided an explanation of the sources of the synoptics (Fitzmyer, The Gospel According to Luke (I-IX), pp. 63-106). Mark was the earliest narrative account of Jesus. References to war in Judea (Mark 13:5-8, 14-19) as well as to persecution (8:34-8; 13:9-13) suggested that it was written during Nero's persecution of Christians in Rome or the Jewish revolt in Judea (c. 66-70 CE; see Donahue, 'Windows and Mirrors'). Independently of each other, Matthew and Luke expanded Mark. Their sayings material (Q) came to each evangelist in different forms (cf. Matthew 5:3-10 and Luke 6:20-6; see Betz, The Sermon on the Mount, pp. 22-44,105-10)- Matthew and Luke sometimes substituted the Q version of an episode for Mark's (cf. Mark 1:12-13; Matthew 4:1-11 and Luke 4:1-13). In other cases, oral tradition underlies the agreements of Matthew and Luke against Mark (e.g. Mark 14:65; Matthew 26:68; Luke 22:64).

When we think of someone as a teacher, we usually think of that person as offering instruction in a school. Pupils are enrolled in the school and follow a system of education established by the school. There were some schools in Jesus' time that would fit this picture. Up until age twelve both boys and girls who lived in cities and towns spent their mornings in schools where they learned the basics of reading and writing. After that age, only boys of wealthier families continued their education. They were sent to teachers who drilled them in the classics, especially the epic poets Homer and Hesiod, and taught them how to speak like educated men. They would study and seek to imitate famous orators like Demosthenes. Rhetoric was the only training for government or public service. Young men learned the duties and behavior appropriate to various offices by imitating older men, especially natural or adoptive fathers and uncles. Sons of craftsmen learned their trade as apprentices. Schools did not train people for later life. Similarly the sons of priests learned what they needed to know for service in the Temple from their fathers.

Jesus, however, did not establish a school with a philosophical doctrine or special method of interpreting the Law. His followers learned by observing what he said and did in different situations. The Gospels refer to a group of Jesus' disciples as the twelve. Mark 3:14–19 pictures the twelve as having been selected from the larger number of followers. They are shown receiving special instruction from Jesus (Mk 4:10; 9:35; Mt 11:1).

Jesus spoke with a prophetic voice to all people. Understanding his message did not require special education or even a life that had been marked by holiness in a special way. Ordinary people heard Jesus' words as the word of God addressed to them. Jesus did not use a “scholarly” or “technical language” such as we find in philosophical writings of the time or in legal disputes over the meaning of the Law. The references to the Law and other images taken from the Hebrew Scriptures are ones that would have been well known to Jesus' audience. Other images in Jesus' teaching reflected the daily life and experience of people.

Since we do not live in Jesus' world as part of our “everyday life,” we often have to use the findings of archaeology and the study of other writings from the time to understand Jesus' images. Even then we may not be sure whether Jesus is simply reporting what people did or whether he has exaggerated a commonplace situation in order to make a point. The well-known Parable of the Sower (Mk 4:3–8) is a good example of this problem:

Established “schools” had a process by which persons became teachers. They would have to spend years as students or disciples of a famous teacher. An outstanding student would then succeed the master. Others might eventually form their own group. We have already seen that Jesus did not come out of such a school. He had not studied the Law with a famous scribe or been part of a group devoted to interpreting the Scriptures like the Pharisees or Essenes. This fact about Jesus lies behind the question preserved in John 7:15: “How does he know letters, since he has not been taught?” This comment does not imply that Jesus was illiterate. He would have been taught to read the Torah scrolls as well as the other forms of reading and writing common in elementary education. But it suggests that Jesus had not been taught how to interpret the Scriptures according to the principles of some school.

Jesus' reply was that he has been taught by God, the one who sent him. Anyone really concerned with doing God's will should recognize the source of his teaching and follow him (Jn 7:16–17). Another scene in John shows that early followers of Jesus also had to face the accusation from Jewish teachers that they were ignorant and could not presume to tell others the truth about God's will. This conflict is “acted out” in a story in which a blind man defends Jesus before hostile Jewish teachers. He is eventually thrown out of the synagogue for believing that Jesus is “from God” (Jn 9:13–34).