Did John invent speeches for Jesus?

James McGrath, a notorious liberal, commented on Michael Kruger's post: "Is the Gospel of John History or Theology?"

I'll quote and comment on his assertions:

"Even if we presume that a reasonable amount of time passed between the composition and redaction of the Synoptic Gospels and the composition and editing of John's Gospel, we are still left wondering how the Gospel of John ended up being so different, and why or what factors led its author (and any subsequent editors who may have been involved with the process) to produce a Gospel that presents Jesus so distinctively."

That's a misleading way of framing the issue. What's initially surprising is not that John's Gospel is so unlike the Synoptics, but why the Synoptics are so alike. The usual explanation is, of course, some version of the two-source theory. To a great extent, Matthew and Luke share common sources–mainly Mark. Since John's Gospel doesn't use the same sources, we'd expect it to be quite different. 

"On the one hand, John’s story claims to be about a historical figure, Jesus, who lived some decades earlier. On the other hand, this claim cannot be taken at face value, since in John one finds that Jesus, John the Baptist, and the narrator all speak in the same way, a way that bears close resemblance also to the language, expressions, and turns of phrase in the Johannine Epistles. So it is clear that, at the very least, the author has passed any traditional material he has inherited through the lens of his own unique perspective and language. In fact, those who know the Gospel of John well should not be surprised to find that a voice other than that of the ‘historical Jesus’ is to be found in it."

i) While it's true that the author of the Fourth Gospel has a fairly homogenous style, McGrath's frame of reference is decidedly odd. I took a quick glance at the Gospels. In the Synoptics, John the Baptist is quoted in Mk 1:7-8, Mt 3:7-12, and Lk 3:7-17. In John's Gospel, the quotes are confined to chap. 1 (vv15,19,21,23,26-27,29,32-34,36) and a snippet in chap. 3 (vv27-30). Jn 3:31-36 is usually taken to be an editorial comment. That's a very slender sampling to form the basis of stylistic comparisons. 

ii) Moreover, many of the Baptist's statements in the Fourth Gospel don't bear a close resemblance to the language, expressions, and turns of phrase in the Johannine Epistles.

iii) Another issue is whether the voice of the Johannine narrator is very similar to the voice of the Johannine Jesus, whereas the voice of, say, the Matthean narrator is dissimilar to the voice of the Matthean Jesus. Unless the narrative technique of Matthew's Gospel is strikingly different from the narrative technique of John's Gospel in that particular regard (i.e. if the narrator's language, expressions, and turns of phrase are dissimilar to Jesus' language, expressions, and turns of phrase), it's unclear what material justifies McGrath's asserted contrast. 

iv) Finally, much of the language reflects common idioms you'd expect to find in discourse that's colored by OT usage as well as the Palestinian landscape and economic lifestyle (e.g. fishing, agriculture). That doesn't reflect a distinctive style. 

To take a comparison, an urban crime novel will use idioms which reflect the urban setting whereas a novel in the Western genre will use idioms which reflect the time and place of the American Old West. There's nothing inherently fictitious about that. To the contrary, that's realistic. Historically accurate. That doesn't reflect a distinctive style; rather, that reflects a distinctive setting. The style echoes the setting.

"The only answer seems to be to regard the author of the Fourth Gospel as doing what was a frequent practice in his time: based on the words of his master, the author created discourses in which he presented what he considers that his master would have said in response to certain new situations which have arisen since his death. One may usefully compare John's presentation of Jesus with Plato's presentation of Socrates' trial, where it is generally assumed that Plato did not present an account of what Socrates said on that occasion, but primarily what he felt that he would have said had he been given the opportunity to answer his accusers at such length. This is not to say that nothing in John stems from the historical Jesus, but simply that the discrepancies between John and the Synoptics necessitate caution, and that we cannot rely on John to present the words of the historical Jesus, in particular when he differs from other sources that have multiple attestation and are generally considered by historians to be more reliable."

This conclusion piggyback's on McGrath's flawed comparison (see above).