Frank Zindler writes:

"The notion that the four "gospels that made the cut" to be included in the official New Testament were written by men named Matthew, Mark, Luke, and John does not go back to early Christian times. The titles "According to Matthew," etc., were not added until late in the second century. Thus, although Papias ca. 140 CE ('Common Era') knows all the gospels but has only heard of Matthew and Mark, Justin Martyr (ca. 150 CE) knows of none of the four supposed authors. It is only in 180 CE, with Irenæus of Lyons, that we learn who wrote the four "canonical" gospels and discover that by this time, the sole justification that we can locate is that that there are exactly four of them because there are four quarters of the earth and four universal winds:

But it is not possible that the Gospels can be either more or fewer in number than they are. For since there are four zones of the world in which we live, and four principal winds, while the church has been scattered throughout the world, and since the "pillar and ground" of the church is the Gospel and the spirit of life, it is fitting that she should have four pillars, breathing incorruption on every side, and vivifying human afresh. From this fact, it is evident that the Logos, the fashioner demiourgos of all, he that sits on the cherubim and holds all things together, when he was manifested to humanity, gave us the gospel under four forms but bound together by one spirit. ”

—Against Heresies 3.11.8

Thus, unless one supposes the argument of Irenæus to be other than ridiculous, (couldn't a Christian come up with an equally ad hoc justication based on the number 1 (one god) 3 (the trinity) 10 (ten commandments) 12 (the disciples)?) we come to the conclusion that the gospels are of unknown origin and authorship, and there is no good reason to suppose they are eye-witness accounts of a man named Jesus of Nazareth. At a minimum, this forces us to examine the gospels to see if their contents are even compatible with the notion that they were written by eye-witnesses. We cannot even assume that each of the gospels had but one author or redactor.

- Did Jesus Exist? by Frank R. Zindler

The following is written by Rook Hawkins concerning the four Gospels.

MARK

John P. Meier provides an example in which the author of Mark shows himself to be dependent on oral tradition. The story of the feeding of the multitude is found twice in Mark and once in John. Meier writes (A Marginal Jew, v. 2, pp. 965-6):

"This suggests a long and complicated tradition history reaching back to the early days of the first Christian generation. Prior to Mark's Gospel there seems to have been two cycles of traditions about Jesus' ministry in Galilee, each one beginning with one version of the feeding miracle (Mk 6:32-44 and Mk 8:1-10). Before these cycles were created, the two versions of the feeding would have circulated as independent units, the first version attracting to itself the story of Jesus' walking on the water (a development also witnessed in John 6), while the second version did not receive such an elaboration. Behind all three versions of the miracle story would have stood some primitive form."

Randel Helms writes concerning Mark 11:1 (Who Wrote the Gospels?, p. 6):

"Anyone approaching Jerusalem from Jericho would come first to Bethany and then Bethphage, not the reverse. This is one of several passages showing that Mark knew little about Palestine; we must assume, Dennis Nineham argues, that 'Mark did not know the relative positions of these two villages on the Jericho road' (1963, 294-295). Indeed, Mark knew so little about the area that he described Jesus going from Tyrian territory 'by way of Sidon to the Sea of Galilee through the territory of the Ten Towns' (Mark 7:31); this is similar to saying that one goes from London to Paris by way of Edinburgh and Rome. The simplist solution, says Nineham, is that 'the evangelist was not directly acquainted with Palestine' (40)."

Concerning v. 9-13, Robert Funk writes in The Five Gospels:

"The sayings in Mark 13:9-13 all reflect detailed knowledge of events that took place - or ideas that were current - after Jesus' death: trials and persecutions of Jesus' followers, the call to preach the gospel to all nations, advice to offer spontaneous testimony, and the prediction that families would turn against one another are features of later Christian existence, not of events in Galilee or Jerusalem during Jesus' lifetime. The note about children betraying their parents may be an allusion to the terrible calamities that took place during the siege of Jerusalem (66-70 C.E.)"

Randel Helms comments on the reference to Daniel in the Gospel of Mark (op. cit., p. :

So Daniel's "time, times, and half a time" is three and a half years, or twelve hundred and ninety days. The author of Daniel was referring, with the "abomination of desolation," to the altar to Zeus that Antiochus IV established in the Jerusalem temple in December, 167 B.C.E., as I Maccabees 1:54 tells us. But in Mark's eyes, Daniel really was speaking of Mark's own time, the "time of the end," when another "abomination of desolation" was set up in the Jerusalem temple. For according to Josephus, the regular offering ceased in the temple in July, 70, the temple was burnt in August, and later that month the imperial Roman eagle was set up in the temple precincts and sacrifice was offered to it; then in September the temple was razed to the ground (Josphus, The Jewish War, Chapters 6, 7). Three and a half years thereafter would be early in the year 74. It should not be surprising that a first-century author might apply the Book of Daniel to the Jewish War; Josephus himself did so, he tells us, in the summer of the year 70, at the height of the seige (Josephus, 309)....As far as Mark was concerned the Jewish War was over; there remained only the cosmic disorder and the Second Coming.

Robert Eisenman writes (James the Brother of Jesus, p. 56):
"From the same internal textual considerations already noted, it is possible to show that Mark, too, was written after the fall of the Temple in 70 CE. The whole nature of its anti-Jewish polemic and opposition to the family and brothers of Jesus on the one hand and its pro-Peter orientation on the other distinguish it as having appeared after the destruction of the Jerusalem centre - in particular, after the attempt by the Roman Community to represent itself as the legitimate heir to Jesus and the Messianic movement he represented, however absurd, historically speaking, that might have seemed to any objective observer at the time."

MATTHEW

As one historian notes:

It is also the consensus position that the evangelist was not the apostle Matthew. Such an idea is based on the second century statements of Papias and Irenaeus. As quoted by Eusebius in Hist. Eccl. 3.39, Papias states: "Matthew put together the oracles [of the Lord] in the Hebrew language, and each one interpreted them as best he could." In Adv. Haer. 3.1.1, Irenaeus says: "Matthew also issued a written Gospel among the Hebrews in their own dialect while Peter and Paul were preaching at Rome and laying the foundations of the church." We know that Irenaeus had read Papias, and it is most likely that Irenaeus was guided by the statement he found there. That statement in Papias itself is considered to be unfounded because the Gospel of Matthew was written in Greek and relied largely upon Mark, not the author's first-hand experience.

Herman N. Ridderbos writes (Matthew, p. 7):

This means, however, that we can no longer accept the traditional view of Matthew's authorship. At least two things forbid us to do so. First, the tradition maintains that Matthew authored an Aramaic writing, while the standpoint I have adopted does not allow us to regard our Greek text as a translation of an Aramaic original. Second, it is extremely doubtful that an eyewitness like the apostle Matthew would have made such extensive use of material as a comparison of the two Gospels indicates. Mark, after all, did not even belong to the circle of the apostles. Indeed Matthew's Gospel surpasses those of the other synoptic writers neither in vividness of presentation nor in detail, as we would expect in an eyewitness report, yet neither Mark nor Luke had been among those who had followed Jesus from the beginning of His public ministry.

J. C. Fenton argues (The Gospel of Saint Matthew, p. 12):

It is usually thought that Mark's Gospel was written about A.D. 65 and that the author of it was neither one of the apostles nor an eyewitness of the majority of the events recorded in his Gospel. Matthew was therefore dependent on the writing of such a man for the production of his book. What Matthew has done, in fact, is to produce a second and enlarged edition of Mark. Moreover, the changes which he makes in Mark's way of telling the story are not those corrections which an eyewitness might make in the account of one who was not an eyewitness. Thus, whereas in Mark's Gospel we may be only one remove from eyewitnesses, in Matthew's Gospel we are at one remove further still.

Francis Write Beare notes (The Gospel according to Matthew, p. 7):

But the dependence of the book upon documentary sources is so great as to forbid us to look upon it as the work of any immediate disciple of Jesus. Apart from that, there are clear indications that it is a product of the second or third Christian generation. The traditional name of Matthew is retained in modern discussion only for convenience.

J.C. Fenton summarizes the evidence for the dating of Matthew as follows (op. cit., p. 11):

The earliest surviving writings which quote this Gospel are probably the letters of Ignatius, the Bishop of Antioch, who, while being taken as prisoner from the East to Rome about A.D. 110, wrote to various churches in Asia in Asia Minor and to the church at Rome. Ignatius refers to the star which appeared at the time of the birth of Jesus, the answer of Jesus to John the Baptist, when he was baptized, and several sayings of Jesus which are recorded only in this Gospel (12:33, 15:13, 19:12). It seems almost certain that Ignatius, and possibly the recipients of his letters also, knew this Gospel, and thus that it was written before A.D. 110. But how long before?

Here we cannot be so certain. But it is possible that we can find evidence that Matthew was writing after the war between the Romans and the Jews which ended in the destruction of the temple at Jerusalem in A.D. 70. See, for example, 22:7: The king was angry, and he sent his troops and destroyed those murderers and burned their city; and compare also 21:41, 27:25. Similarly, Matthew's Gospel contains a strongly anti-Jewish note running through it, from the teaching not to do as the hypocrites do in Chapter 6, to the Woes on the scribes and Pharisees in Chapter 23; and this may point to a date after c. A.D. 85 when the Christians were excluded from the Jewish synagogues. It is worth noting here that Matthew often speaks of their synagogues (4:23, 9:35, 10:17, 12:9, 13:54), as if to distinguish Christian meetings and meeting places from those of the Jews, from which the Christians had now been turned out.

Beare offers the following to date the Gospel of Matthew (op. cit., pp. 7-8):

It is generally agreed that it was written after the fall of Jerusalem to the armies of Titus (AD 70), and the widespread acquaintance with it which is exhibited in all the Christian literature of the second century makes it difficult to place its composition any later than the opening decade of that century. If the Sermon on the Mount can be regarded in any sense as 'the Christian answer to Jamnia. . . a kind of Christian mishnaic counterpart to the formulation taking place there' (Davies, Setting, p. 315), this would indicate a date a few years before or after the turn of the century.

Concerning the knowledge of the fall of Jerusalem that the author evinces, Schweizer writes concerning Matthew 22:7 (op. cit., p. 418):

The wrath of the host is mentioned by both evangelists, but it is impossible to conceive of the king coming with his army not only to slay those who had been invited but to burn down their city (not "cities"), and doing all this while the feast stands ready for the newly invited. The parable deals with ordinary citizens, who buy fields and use oxen, not with men who rule entire cities. After his punishment, furthermore, the verdict of the king in verse 8 is pointless. Verses 6-7 are thus clearly an interpolation in the narrative, which earlier passed directly from verse 5 to the wrath of the king (beginning of vs. 7), and then to verse 8. Here the events of A.D. 70 - the taking and burning of Jerusalem by Roman armies - have colored the language of the parable.

LUKE

The very opening of the book of Luke informs us that we do not have an eyewitness account:

Many have undertaken to draw up an account of the things that have been fulfilled among us, just as they were handed down to us by those who from the first were eyewitnesses and servants of the word. [Luke 1:1-2 NIV]

F. F. Bruce writes on the occasion of Luke's writing (The Book of Acts, pp. 10-12):

It is necessary, then, to look for an appropriate life-setting for a work which strikes the apologetic note in just this way. One attractive suggestion points to the period A.D. 66 or shortly afterward, when the chief accusers of Paul, the Judean authorities, ahd so completely discredited themselves in Roman eyes by the revolt against imperial rule. True, Paul himself was dead by then, but the accusations against him, especially that of fomenting public disorder, continued to be brought against Christians in general, and his defense, which could have been seen as vindicated in the event, might be validly pleaded on their behalf. In those years it would have been quite effective to emphasize that, unlike the rebellious Jews, Christians were not disloyal to the empire--that, in fact, it was the rebellious Jews themselves who had always done their best to disown Christianity.

The argument that there is nothing in Acts--or even in Luke--that presupposes the Jewish revolt and the resultant destruction of the temple and city of Jerusalem (A. D. 70) has been used in defense of a pre-70 dating for the twofold work--early in the twentieth century by Adolf Harnack and over sixty years later by J. A. T. Robinson. Indeed, it has been further argued, since there is no allusion to two earlier events--the Neronian persecution and the execution of Paul--that the composition of Luke-Acts should probably be dated not later than A.D. 65. So far as the Neronian persecution is concerned, even Tacitus (no friend to Christians) admits that it was the action of one man's malignity rather than an expression of public policy, and the official reprobation of Nero's memory and actions at his death could have been held to cover his persecution of the Christians of Rome. So Luke's recording of favorable judgments which had been passed on Christianity by other Roman authorities might have been intended to suggest that Nero's anti-Christian activity was an irresponsible and criminal attack by that now excrated ruler on a movement whose innocence had been amply attested by many worthier representatives of Roman power.

Again, whether Paul's execution was or was not an incident in the Neronian persecution, the fact that it is not mentioned in Acts is not a decisive argument for the dating of the book: Luke's goal has been reached when he has brought Paul to Rome and left him preaching the gospel freely there. Certainly, Paul's arrival in Rome, his gospel witness there for two years, the legal procedure involved in the bearing of his appeal to Caesar, must have brought Christianity to the notice of classes in Roman society on which it had until then made no impression. The interest that was now aroused in it did not die out, but maintained itself and increased, until under Domitian (A.D. 81-96) it had penetrated the highest ranks of all. At any time in this period a work which gave an intelligible history of the rise and progress of Christianity, and at the same time gave a reasoned reply to popular calumnies against it, was sure of a reception amongst the intelligent reading public--or rather listening public--of Rome, of whom Theophilus was probably a representative. Its positive defense was best expressed in the words of Paul, the Roman citizen, whose appeal to Caesar was made not only on his own behalf but on behalf of the Christian community and its faith.

It is difficult to fix the date of composition of Acts more precisely than at some point within the Flavian period (A.D. 69-96), possibly about the middle of the period. The arguments by which Sir William Ramsay, late in the nineteenth century, concluded that it was composed about A.D. 80 are precarious, but nothing that has been discovered since then has pointed to a more probable dating. One consideration, admittedly subjective, is the perspective from which the work has been composed. The relations between Peter, Paul, and James of Jerusalem are presented in a way which would be more natural if all three of them had died and the author had been able to view their lasting achievements in a more satisfactory proportion than would have been so easily attained if they had still been alive. Certainly the impression he gives us of their relations is not the impression received from Paul's letters, and this is more intelligible if they had been dead for some years and their disagreements (in the eyes of a man like Luke, at any rate) no longer seemed as important as they would have done at the time.

Stevan Davies writes (Jesus the Healer, p. 174):
"Luke wrote at least sixty years after Pentecost and perhaps closer to a century after that event. Scholarship on the subject presently vacillates between a late first century and an early to mid-second century date for Luke's writings."

JOHN

Robert Kysar writes the following on the authorship of the Gospel of John (The Anchor Bible Dictionary, v. 3, pp. 919-920):

The supposition that the author was one and the same with the beloved disciple is often advanced as a means of insuring that the evangelist did witness Jesus' ministry. Two other passages are advanced as evidence of the same - 19:35 and 21:24. But both falter under close scrutiny. 19:35 does not claim that the author was the one who witnessed the scene but only that the scene is related on the sound basis of eyewitness. 21:24 is part of the appendix of the gospel and should not be assumed to have come from the same hand as that responsible for the body of the gospel. Neither of these passages, therefore, persuades many Johannine scholars that the author claims eyewitness status.

Morton Enslin observes (Christian Beginnings, pp. 369-370):

That Papias’ source of information is simply an inference from Mark 10:35-40 or its parallel, Matt. 20:20-23, is possible. None the less, this Marcan passage itself affords solid ground. No reasonable interpretation of these words can deny the high probability that by the time these words were written [ca. 70 CE] both brothers had 'drunk the cup' that Jesus had drunk and had been 'baptized with the baptism' with which he had been baptized." Since the patristic tradition is unanimous in identifying the beloved disciple with John, at least this evidence discredits the patristic tradition concerning the authorship of the Gospel of John.

Kysar states concerning the dating of the Gospel of John:

"Those who relate the expulsion to a formal effort on the part of Judaism to purge itself of Christian believers link the composition of the gospel with a date soon after the Council of Jamnia, which is supposed to have promulgated such an action. Hence, these scholars would date John after 90. Those inclined to see the expulsion more in terms of an informal action on the part of a local synagogue are free to propose an earlier date." (p. 919)