Jesus was indeed not a real person but at the most he was entirely nothing like we think.
Who is "we"? Every monograph, books, or set of volumes by some author on Jesus portrays the historical person differing from every other portrait in some way (which holds true of modern biographies of those still living and of those recently deceased). Usually, the differences concern which of the "roles" he played (teacher, prophet, preacher, would-be messiah, sectarian leader, etc.) was more focal than another or didn't exist at all (like the Jewish Cynic of Crossan and others).
There is no direct evidence to support his existence despite the literacy and constant recording in Greek history.
If this constant recording in Greek history ever existed, we have no evidence of it. In a period spanning ~1,000 years, we have significant portions of only a handful of ancient "biographies", usually written a century or more after the death of person the biographer wrote about.
Also, what would "direct evidence" constitute?
For example, we have inscriptions or similar evidence on statues, mosaics, vases, etc., bearing the names of famous emperors. We have the same evidence for deities and mythical heroes (especially those of Homer).
We have literary records, such as the works of Plato. Only his depiction of Socrates is fundamentally different not only from other portraits of Socrates, but from his own. Hence the comment by Vlastos that the only way Plato's Socrates could be a real person was if Socrates were schizophrenic (I think he probably meant to refer to multiple personality disorder/DID, or otherwise associated schizophrenia with personality disorders that involve abrupt, significant personality changes). Then there is the fact that we have letters of Plato all of which may be pseudepigrapha and some of which definitely are.
We have biographers like Diogenes Laerties writing about philosophers who lived many centuries ago and which contain mythical accounts of miracles or magic, rumor, legends, and other components that would not counted as biographical today.
We have reports written by Caesar
1) Which we don't know if he wrote in pieces, sending back propaganda, or composed as a whole
2) That speak of mythical creatures
3) That are clearly designed to be propaganda (and contain, as a result of this intention, lies and distortions).
We have an enormous amount of evidence about Greco-Roman religious (cultic) practice and the formation of Jewish monotheism. Our knowledge of the first century of the roman empire in general and Galilee and similar regions in particular has improved vastly by sociological studies and the final report on the years spent excavating in Galilee. There's still a lot we don't know about aspects of Jewish religion during Jesus' day (what role did the synagogue play, to what extend were the Pharisees as prominent before the 30s, did the typical person living in Judaea or in the diaspora tend to lend credence to the notion of an oral torah, how long did it take those who were or were akin to the Pharisees to go from what they were before the destruction of the temple to becoming rabbis, and when did torah study replace the "temple" in terms of religious function, etc.). However, thanks to those like Neusner, Vermes, Horsley, Feldman, and many others, we are significantly better informed than we were a mere 30 years ago.
Which brings us to secondary sources. The biblical and classical scholars who created historical-critical analysis, lexicography, comparative and historical linguistics, textual criticism, etc. The historical Jesus was a focus of study before Reimarus, he was just the first to focus on the entirety of the evidence and not just to determine whether some particular component of the historical Jesus was wrong, but whether there was any basis for Christianity. He didn't deny Jesus existed, but as we haven't even gotten to the 18th century yet. By the 1830s, Strauß had already defeated the attempts of the rationalists to recover a non-miracle Jesus, and perhaps his greatest critic was Bauer, the first mythicist. And we're still in the 1830s. A century later, the only mythicists left were amateurs, as they were the only ones unfamiliar with the historical scholarship by mythicists and the responses.
There is only one other person who was and is as studied (or nearly) as the historical Jesus: the historical Socrates. In fact, some of the same scholars contributed to the study of both. So the question becomes, how did they all get it so wrong? How did the disciplines which created modern history as we know it, as well as the tools used today by every historian of the ancient world, fail to understand after 200+ years that Jesus was a myth?
Perhaps because they didn't.
1) They were historians continually refining their craft which today incorporates studies from anthropology; methods in linguistics; the psychology of memory, perception, and the nature of cognitive errors in human judgment from cognitive science research; models of orality before it became a field unto itself and after; socioeconomic models; the scientific study of religion and religious movements; archaeology; and much more.
2) Mythicists are typically unable even to read most of both the primary and secondary literature even were they so inclined.
3) Most wouldn't read it even if they could, a fact evidenced by the almost utter lack of any research whatsoever among the plethora of studies written in English.
4) They rely on amateurs to form an opinion of what the study of ancient history typically involves that is grossly inaccurate.
5) Most of the various blogs, books, and other mythicist writings are filled with errors. Such authors misquote their sources, sensationalize, ignore inconvenient methods or facts as well as scholarship, and make things up (e.g., Archarya S/D. M. Murdock's use of Herodotus to show that the Hellenistic Mithras was around before Jesus by reference to a passage about a goddess).
Unfortunately, most of the scholarship on the subject is either non-technical and therefore unconvincing, or is difficult to obtain and frequently too technical to understand. But there have been and still are decent books which are not nearly as long as Meier's 4 volume account, yet are not as simplistic as Ehrman's popular books, and which are designed to demonstrate why historians believe we have more than enough evidence to say Jesus existed (as well as some other basic facts). They do not start with the assumption that Jesus existed.
However, despite the fact that they are quite willing to buy books by Carrier or Ehrman (before his latest, anyway), mythicists are more likely to have read Doherty or Wells than to have read any of the various books of the type mentioned above. They don't want to be objective, and so they read selectively.
Meanwhile, outside of this tiny bubble is a massive amount of research which has become increasingly sophisticated and interdisciplinary in volumes, journals, monograph series, etc., that are almost never mentioned in any mythicist writings ever. Most don't know these exist. They assume that the field is of a particular nature because they are told that by amateurs repeatedly and this stance becomes dogma. It is given as an excuse not to do research, it is given as a reason that virtually no historians in almost a century have argued that Jesus is a myth (but have addressed mythicist arguments), and becomes a foundation for constructing an illusion not just of historical Jesus research but of the entire study of ancient history.
It's the reason for statements like this: "the literacy and constant recording in Greek history" which anybody who read Carrier's dissertation would know is false.
Another individual who surprisingly did not exist was Muhammad for example. He did not exist in the manner in which we think now.
There is no equivalent to the historical Jesus quest or the Socratic problem within scholarship on Muhammad. First, very few Western scholars cared that much. Second, the "historical" scholarship within Islam has a lengthy tradition which relies on methods that aren't considered historical today. Third, biblical scholars have said everything from "all of Christianity is based on a mutation of what Jesus actually preached" to "Jesus was a hippie whose body was eaten by dogs". However, a sketch of Muhammad can initiate a fatwa and cause a national debate. So even though historical scholarship does exist, there isn't much and it has tended to accept the division of
ahadith established centuries ago.
That said, like Jesus and Socrates, we know at least that they existed and some other basic facts. It's just that for the other two we can go farther by looking at what the vast majority of historical scholarship has demonstrated convincingly (relative to radical ideas like e.g., Craig's use of "history" to show Jesus rose from the dead or Eisenman's analysis of the Qumran finds). No such wealth of scholarship exists for Muhammad.
*pulls up chair and waits with a smile on face for Legion's response*
