Tuesday, March 18, 2014

Cartoons and Fables - How Cosmos Got the Story of Bruno Wrong

The Giordano Bruno Monument - Campo di Fiori, Rome - October 2013
(I was invited to write a post on this subject by Thony Christie for his excellent history of science blog, The Renaissance Mathematicus.  Many thanks to him for the invitation.  I'm reproducing my post here for Armarium Magnum readers)


A few months ago while visiting Rome I did something a tourist should not do in a strange city - I took a short cut.  Walking back from the Forum to my apartment over the Tiber, I should have taken the obvious route down the Corso Vittorio Emanuele II toward the Castel  Saint 'Angelo, but I decided I knew where I was going, so I took a more direct path through some back streets and soon became completely lost.  After winding my way through a maze of smaller laneways trying to find a major road I saw a piazza up ahead and so decided to use that to get my bearings.  I stopped under a statue in the middle of the square to get out a map, looked up at the statue and immediately knew where I was.  I realised I was in the Campo de'Fiori, because the statue was the famous monument to Giordano Bruno, raised on the spot where he was burned at the stake in February 1600.

Bruno is the poster boy of the Draper-White Thesis - the idea that science and religion have always been at war and an idea beloved by the New Atheist movement despite the fact it was rejected by actual historians of science about a century ago.  Try to engage in an attempt at intelligent discussion of the real and much more complex and nuanced interrelations between religion and what was to emerge as modern science in the medieval and early modern periods and Bruno is usually brandished as "proof" that the Church was the implacable and ignorant foe of early science.  After all, why else did they burn him for daring to say the earth wasn't the centre of the universe and that the stars were other suns with planets?  For those who prefer simple slogans and caricatures to the hard work of actually analysing and understanding history, Bruno is a simple answer to a intricate question.  Nuance and complexity are the first casualties in a culture war.

So when I saw the first preview clips of the revamped version of Carl Sagan's Cosmos, this time presented by Sagan's genial protégé Neil deGrasse Tyson, and noticed an animated sequence of someone being menaced by Inquisitors and burned at the stake, I knew that the revived Cosmos was going to be presenting some bungled history.  This was also following in Sagan's footsteps, I suppose, since in the original series he veered off into a mangled version of the story of Hypatia of Alexandria that fixed the false idea of her as a martyr for science in the minds of a generation, as I've discussed elsewhere.

So when the first instalment of the new series - Cosmos: A Spacetime Odyssey -  went to air last week, at its heart was an eleven minute version of the Bruno myth.  I often refer to the simplistic moral fable that people mistake for the history of the relationship between the Church and early science as "the cartoon version", because it's oversimplified, two-dimensional and reduced to a black and while caricature.  But in this case it really is a cartoon version - the sequence was animated, with the voice of Bruno provided by the series' Executive Producer, Seth MacFarlane, of Family Guy fame, which seems to be why Bruno has an Italian accent of a kind usually heard in ads for pizza or pasta sauce.

The clichés didn't end with the silly accents.  In the weirdly distorted version of the story the program tells, Bruno is depicted as an earnest young friar in Naples who was a true seeker after truth.  But DeGrasse Tyson assures us that he "dared to read the books banned by the Church and that was his undoing."   We then get a sequence of Bruno reading  a copy of Lucretius' On the Nature of Things which he has hidden under the floorboards of his cell.  The first problem here is that Lucretius' work was not "banned by the Church" at all and no-one needed to hide it under their floor.  Poggio Bracciolini had published a printed edition of the book a century before Bruno was born and it had never been banned when the medieval manuscripts Bracciolini worked from had been copied nor was it banned once his edition made it widely available.  The idea that the Church banned and/or tried to destroy Lucretius' work is a myth that Christopher HItchens liked to repeat and which has been given a lease of popular life via Stephen Greenblatt's appalling pseudo historical work The Swerve, which somehow won a Pulitzer Prize despite being a pastiche of howlers.

The DeGrasse Tyson cartoon goes on to depict Bruno having his mind opened to the idea of an infinite universe by Lucretius' book but then being kicked out of his friary by a mob of Disney villain-style Church types who turn up unexpectedly like Monty Python's Spanish Inquisition.  This, of course, makes for a much better parable than the truth - Lucretius' work wasn't "banned by the Church" and Bruno actually ran away from his religious house and wasn't thrown out for reading naughty books.

It would also have complicated this simplistic cartoon fable to note where Bruno got his ideas about a vast cosmos where the earth was not the centre, where the stars were other suns, where there was a multiplicity of worlds and where some of these other worlds could even have been inhabited just like ours.  Because this was not something Bruno got from Lucretius nor was it something he dreamed up himself in a vision, as the Cosmos cartoon alleges.  It's something he drew directly from the man he called "the divine Cusanus" - the fifteenth century natural philosopher and theologian Nicholas of Cusa.

If the writers of the series were actually interested in the real history of the origins of scientific thought, there are many people whose stories would have been far more worthy of telling than Bruno - people who actually were proto-scientists.  The writers of the show, Steven Soter and Sagan's widow Ann Druyan, seem to have known enough about Bruno to know they could not present him as a scientist and DeGrasse Tyson's narration does mention that he was "no scientist" at one point.  But they delicately skim over the fact that the guy was, to our way of thinking, a complete mystical loon.  In his defence of the criticism the Bruno sequence has since attracted Soter notes that several  other early science figures also pursued studies that we find abjectly unscientific, such as Newton's obsessions with alchemy and apocalyptic calculation.  But the difference is that Newton and Kepler pursued those ideas as well as studies that were based on real empirical science, whereas Bruno's hermetical mysticism, sacred geometry and garbled and largely invented ancient Egyptian religion were all of his studies - he did no actual science at all.

But if they wanted to be truly accurate they should have detailed or even merely acknowledged Bruno's debt to Nicholas of Cusa, who expounded on a non-finite cosmos without a centre 109 years before Bruno was even born.  Here is Cusanus on the subject in his book De docta ignorantia

" The universe has no circumference, for if it had a centre and a circumference there would be some and some thing beyond the world, suppositions which are wholly lacking in truth. Since, therefore, it is impossible that the universe should be enclosed within a corporeal centre and corporeal boundary, it is not within our power to understand the universe, whose centre and circumference are God. And though the universe cannot be infinite, nevertheless it cannot be conceived as finite since there are no limits within which it could be confined."

That's the insight that the Bruno cartoon attributes solely to Bruno.  So why not attribute it to "the divine Cusanus"?  Well, that would ruin the whole parable.  Because far from being kicked around by grim-looking Disney villains imprisoned and burned at the stake, Cusanus was revered and actually made a cardinal.  So that doesn't lend itself very well to a moral fable about free-thinking geniuses being oppressed by dogmatic theocrats.

The cartoon then goes on to depict brave Bruno lecturing at Oxford, with grumpy and aristocratic-sounding scholars there objecting to his espousal of Copernicanism and eventually throwing fruit at him and driving him away.  Again, the reality wasn't quite as worthy.  There is zero record of any objection to heliocentrism and the problem the Oxford scholars had with Bruno was actually his plagiarism of another scholar's work.  But, again, that doesn't lend itself to a fable about a pure and persecuted freethinker.

Throughout the cartoon the idea is that he is afflicted because he supports heliocentrism and the idea of an unbounded cosmos  where the earth is not the centre.  As we've seen, the latter idea was not new and not controversial.  By the 1580s Copernicus' heliocentric hypothesis wasn't particularly new either, though it was more controversial - virtually no astronomers accepted it because it was recognised as having severe scientific flaws.  The important point to remember here is that at  that stage it was not considered heretical by religious authorities, even though some thought it had some potentially bothersome implications.

Copernicus had not even been the first proto-scientist to explore the idea of a moving  earth.  The medieval scholar Nicholas Oresme had analysed the evidence that supported the idea the earth rotated way back in 1377 and regarded it as at least plausible.  The Church didn't bat an eyelid.  Copernicus' calculations and his theory had been in circulation long before his opus was published posthumously and it had interested several prominent churchmen, including Pope Clement VII, who got Johan Widmanstadt to deliver a public lecture on the theory in the Vatican gardens, which the Pope found fascinating.  Nicholas Cardinal Schoenburg then urged Copernicus to publish his full work, though Copernicus delayed not because of any fear of religious persecution but because of the potential reaction of other mathematicians and astronomers.  Heliocentrism didn't become a religious hot topic until the beginning of the Galileo affair in 1616, a decade and half after Bruno's death.

Again, the Cosmos writers seem to be at least vaguely aware of all this and so do some fancy footwork to keep their parable on track.  In the cartoon's depiction of Bruno's trial we get the first hint that the Church's beef with Bruno might actually have been to do with ideas that had zero to do with an infinite cosmos, multiple worlds or any cosmological speculations at all.  So the Disney villain Inquisitor reads out a list of accusations such as "questioning the Holy Trinity and the divinity of Jesus Christ" and a few other purely religious charges.  The depiction gives the impression that these are somehow less important or even trumped up accusations, when in fact these are the actual reasons Bruno was burned at the stake, along with others beside.  As horrific as it is to us, denying the virginity of Mary, saying Jesus was merely a magician and denying Transubstantiation did get you burned in 1600 AD, though only if you refused repeated opportunities to recant.

But the cartoon wants to stick to its parable, so they tack on the final and, we are led to believe, most serious charge - "asserting the existence of other worlds".  As we've already seen, however, this was not actually a problem at all.  Here's NIcholas of Cusa on these other worlds in the book that inspired many of Bruno's beliefs:

"Life, as it exists on Earth in the form of men, animals and plants, is to be found, let us suppose in a high form in the solar and stellar regions. Rather than think that so many stars and parts of the heavens are uninhabited and that this earth of ours alone is peopled – and that with beings perhaps of an inferior type – we will suppose that in every region there are inhabitants, differing in nature by rank and all owing their origin to God, who is the center and circumference of all stellar regions .... Of the inhabitants then of worlds other than our own we can know still less having no standards by which to appraise them."

Again, remember that Cusanus was not burned at the stake, he was revered, praised and made a cardinal.

The only mention of other worlds in the accusations against Bruno specifies that he believed in "a plurality of worlds and their eternity".  It was that last part that was the problem, not subscribing to an idea that a prince of the Church had espoused a century earlier.

The cartoon concludes with DeGrasse Tyson's caveats about Bruno being "no scientist" and his ideas being no more than a "lucky guess".  Some commenters seem to think that this somehow absolves the whole sequence of its distortions and that it means the show depicts Bruno only as a martyr to free thought and a lesson on the dangers of dogmatism.  But the problem with the cartoon is that it makes up a silly pastiche of real history, fantasy and oversimplified nonsense to achieve this aim.  The real story of Cusanus would actually have been a much more interesting one to tell and wouldn't have had the Draper-White inspired baggage of the Bruno myths.  But the whole sequence seems to have had an agenda and a burned heretic story served that agenda's purpose in a way that a revered and untrammelled medieval cardinal's story would not have.

The objective here was to make a point about free thought and dogmatism in the context of the culture wars in the US about Creationism.  That Bruno was a believer in God was an idea that was repeated several times in the cartoon, even though he was actually more of a pantheist than anything.  But he is depicted as an open-minded and unconstrained believer who is oppressed and finally killed by the forces of dogmatic literalism.  The cartoon Bruno's cry to the fruit-throwing Oxford scholars  - "Your God is too small!" - is actually the point of the whole parable.  This entire sequence was aimed at the dogmatic literalists in the American culture war while still trying to appeal to believers, given the majority of the show's American audience would have been theists.  That's the framework of this fable and the writers chopped up bits of the actual historical Bruno story and then clumsily forced them into this modern message.  

Which brings me back to my encounter with the statue in the Campo de'Fiori.  The statue was created by Ettore Ferrari and erected in 1889 in the wake of the unification of Italy in the face of Church opposition.  The monument, raised by members of the Grande Orient d'Italia Masonic order, was a deliberate political symbol of anti-clericalism.  Atheists and free thinkers revere it to this day and commemorate Bruno's execution on Febrary 17 each year.

Of course, anyone who points out that Bruno is a rather ridiculous icon for atheists, given his kooky mystical views and magical practices is usually ignored.  And anyone who has the temerity to point out that he was executed for purely religious ideas and not any speculation about multiple worlds or a non-finite cosmos is usually (bizarrely) told they are somehow justifying his horrific execution.  As I've often noted, for people who call themselves rationalists, many of my fellow atheists can be less than rational.  Unfortunately, Neil deGrasse Tyson, Ann Druyan, Steven Soter and Seth MacFarlane's silly Bruno cartoon will definitely not help in that regard.

Saturday, January 18, 2014

Did Jesus Exist? The Jesus Myth Theory, Again.




(A version of this article appeared on Quora, where it became the top-voted answer to the question "Do credible historians agree that the man named Jesus, who the Christian Bible speaks of, walked the earth and was put to death on a cross by Pilate, Roman governor of Judea?".  In the year since I posted it there, it has been linked to and recommended on a variety of fora, but some people don't like the fact they have to join Quora to read it.  So I am posting it here for those who would appreciate easier access to it.)


Background

Scholars who specialise in the origins of Christianity agree on very little, but they do generally agree that it is most likely that a historical preacher, on whom the Christian figure "Jesus Christ" is based, did exist.  The numbers of professional scholars, out of the many thousands in this and related fields, who don't accept this consensus, can be counted on the fingers of one hand.  Many may be more cautious about using the term "historical fact" about this idea, since as with many things in ancient history it is not quite as certain as that.  But it is generally regarded as the best and most parsimonious explanation of the evidence and therefore the most likely conclusion that can be drawn.

The opposite idea - that there was no historical Jesus at all and that "Jesus Christ" developed out of some purely mythic ideas about a non-historical, non-existent figure - has had a chequered history over the last 200 years, but has usually been a marginal idea at best.  Its heyday was in the late Nineteenth and early Twentieth Century, when it seemed to fit with some early anthropological ideas about religions evolving along parallel patterns and being based on shared archetypes, as characterised by Sir James Frazer's influential comparative religion study The Golden Bough (1890). But it fell out of favour as the Twentieth Century progressed and was barely held by any scholars at all by the 1960s.

More recently the "Jesus Myth" hypothesis has experienced something of a revival, largely via the internet, blogging and "print on demand" self-publishing services.  But its proponents are almost never scholars, many of them have a very poor grasp of the evidence and almost all have clear ideological objectives.  Broadly speaking, they fall into two main categories: (i) New Agers claiming Christianity is actually paganism rebadged and (ii) anti-Christian atheist activists seeking to use their "exposure" of historical Jesus scholarship to undermine Christianity.  Both claim that the consensus on the existence of a historical Jesus is purely due to some kind of iron-grip that Christianity still has on the subject, which has suppressed and/or ignored the idea that there was no historical Jesus at all.

In fact, there are some very good reasons there is a broad scholarly consensus on the matter and that it is held by scholars across a wide range of beliefs and backgrounds, including those who are atheists and agnostics (e.g. Bart Ehrman, Maurice Casey, Paula Fredriksen) and Jews (e.g. Geza Vermes, Hyam Maccoby).



Unconvincing Arguments for a Mythic Origin for Jesus

Many of the arguments for a Mythic Jesus that some laypeople think sound highly convincing  are exactly the same ones that scholars consider laughably weak, even though they sound plausible to those without a sound background in the study of the First Century.  For example:

1.  "There are no contemporary accounts or mentions of Jesus.  There should be, so clearly no Jesus existed."

This seems a good argument to many, since modern people tend to leave behind them a lot of evidence they existed (birth certificates, financial documents, school records) and prominent modern people have their lives documented by the media almost daily.  So it sounds suspicious to people that there are no contemporary records at all detailing or even mentioning Jesus. 

But our sources for anyone in the ancient world are scarce and rarely are they contemporaneous - they are usually written decades or even centuries after the fact.  Worse still, the more obscure and humble in origin the person is, the less likely that there will be any documentation about them or even a fleeting reference to them at all.

For example, few people in the ancient world were as prominent, influential, significant and famous as the Carthaginian general Hannibal.  He came close to crushing the Roman Republic, was one of the greatest generals of all time and was famed throughout the ancient world for centuries after his death down to today.  Yet how many contemporary mentions of Hannibal do we have?  Zero.  We have none.  So if someone as famous and significant as Hannibal has no surviving contemporary references to him in our sources, does it really make sense to base an argument about the existence or non-existence of a Galilean peasant preacher on the lack of contemporary references to him?  Clearly it does not.

So while this seems like a good argument, a better knowledge of the ancient world and the nature of our evidence and sources shows that it's actually extremely weak.

2.  "The ancient writer X should have mentioned this Jesus, yet he doesn't do so.  This silence shows that no Jesus existed."

An "argument from silence" is a tricky thing to use effectively.  To do so, it's not enough to show that a writer, account or source is silent on a given point - you also have to show that it shouldn't be before this silence can be given any significance.  So if someone claims their grandfather met Winston Churchill yet a thorough search of the grandfather's letters and diaries of the time show no mention of this meeting, an argument from silence could be presented to say that the meeting never happened.  This is because we could expect such a meeting to be mentioned in those documents.

Some "Jesus Mythicists" have tried to argue that certain ancient writers "should" have mentioned Jesus and did not and so tried to make an argument from silence on this basis.  In 1909 the American "freethinker" John Remsberg came up with a list of 42 ancient writers that he claimed "should" have mentioned Jesus and concluded their silence showed no Jesus ever existed.  But the list has been widely criticised for being contrived and fanciful.  Why exactly, for example, Lucanus - a writer whose works consist of a single poem and a history of the civil war between Caesar and Pompey (in the century before Jesus' time) "should" have mentioned Jesus is hard to see.  And the same can be said for most of the other writers on Remsberg's list.

Some others, however, are more reasonable at first glance.  Philo Judaeus was a Jew in Alexandria who wrote philosophy and theology and who was a contemporary of Jesus who also mentions events in Judea and makes reference to other figures we know from the gospel accounts, such as Pontius Pilate.  So it makes far more sense that he "should" mention Jesus than some poets in far off Rome.  But it is hard to see why even Philo would be interested in mentioning someone like Jesus, given that he also makes no mentions of any of the other Jewish preachers, prophets, faith healers and Messianic claimants of the time, of which there were many.  If Philo had mentioned Anthronges and Theudas, or Hillel and Honi or John the Baptist and the "Samaritan Prophet" but didn't mention Jesus, then a solid argument from silence could be made.  But given that Philo seems to have had no interest at all in any of the various people like Jesus, the fact that he doesn't mention Jesus either carries little or no weight.

In fact, there is only one writer of the time who had any interest in such figures, who also had little interest for Roman and Greek writers.  He was the Jewish historian Josephus, who is our sole source for virtually all of the Jewish preachers, prophets, faith healers and Messianic claimants of this time.  If there is any writer who should mention Jesus, it's Josephus.  The problem for the "Jesus Mythicists" is ... he does.  Twice, in fact.  He does do so in Antiquities XVIII.3.4 and again in Antiquities XX.9.1.  Mythicists take comfort in the fact that the first of these references has been added to by later Christian scribes, so they dismiss it as a wholesale interpolation.  But the majority of modern scholars disagree, arguing there is solid evidence to believe that Josephus did make a mention of Jesus here and that it was added to by Christians to help bolster their arguments against Jewish opponents.  That debate aside, the Antiquities XX.9.1 mention of Jesus is universally considered genuine and that alone sinks the Mythicist case (see below for more details).

3.  "The earliest Christian traditions make no mention of a historical Jesus and clearly worshipped a purely heavenly, mythic-style being.  There are no references to an earthly Jesus in any of the earliest New Testament texts, the letters of Paul."

Since many people who read Mythicist arguments have never actually read the letters of Paul, this one sounds convincing as well.  Except it simply isn't true.  While Paul was writing letters about matters of doctrine and disputes and so wasn't giving a basic lesson in who Jesus was in any of this letters, he does make references to Jesus' earthly life in many places.  He says Jesus was born as a human, of a human mother and born a Jew (Galatians4:4).  He repeats that he had a "human nature" and that he was a human descendant of King David (Romans1:3).  He refers to teachings Jesus made during his earthly ministry on divorce (1Cor. 7:10), on preachers (1Cor. 9:14) and on the coming apocalypse (1Thess. 4:15).  He mentions how he was executed by earthly rulers (1Cor. 2:8) and that he died and was buried (1Cor 15:3-4).  And he says he had an earthly, physical brother called James who Paul himself had met (Galatians1:19). 

So Mythicist theorists then have to tie themselves in knots to "explain" how, in fact, a clear reference to Jesus being "born of a woman" actually means he wasn't born of a woman and how when Paul says Jesus was "according to the flesh, a descendant of King David" this doesn't mean he was a human and the human descendant of a human king.  These contrived arguments are so weak they tend to only convince the already convinced.  It's this kind of contrivance that consigns this thesis to the fringe.
 




The Problems with a "Mythic" Origin to the Jesus Story

The weaknesses of the Mythicist hypothesis multiply when its proponents turn to coming up with their own explanation as to how the Jesus stories did arise if there was no historical Jesus.  Of course, many of them don't really bother much with presenting an alternative explanation and leave their ideas about exactly how this happened conveniently vague.  But some realise that we have late First Century stories that all claim there was an early First Century person who lived within living memory and then make a series of claims about him.  If there was no such person, the Mythicist does need to explain how the stories about his existence arose and took the form they do. And they need to do so in a way that accounts for the evidence better than the parsimonious idea that this was believed because there was such a person.  This is where Mythicism really falls down.  The Mythicist theories fall into four main categories:

1. "Jesus was an amalgam of earlier pagan myths, brought together into a mythic figure of a god-man and saviour of a kind found in many cults of the time."

This is the explanation offered by the New Age writer who calls herself "Acharya S" in a series of self-published books beginning with The Christ Conspiracy: The Greatest Story Ever Sold (1999).  Working from late Nineteenth and early Twentieth Century  theosophist claims which exaggerate parallels between the Jesus stories and pagan myths, she makes the typical New Age logical leap from "similarity" to "parallel" and finally to "connection" and "causation".  Leaving aside the fact that many of these "parallels" are highly strained, with any miraculous conception or birth story becoming a "virgin birth" or anything to do with a death or a tree becoming a "crucifixion" (even if virginity or a cross is not involved in either), it is very hard to make the final leap from "parallel" to "causation".

This is particularly hard because of the masses of evidence that the first followers of the Jesus sect were devout Jews - a group for whom the idea of adopting anything "pagan" would have been utterly horrific.  These were people who cut their hair short because long hair was associated with pagan, Hellenistic culture or who shunned gymnasia and theatres because of their association with pagan culture.  All the evidence actually shows that the earliest Jesus sect went through a tumultuous period in its first years trying to accommodate non-Jews into their devoutly Jewish group.  To claim that these people would merrily adopt myths of Horus and Attis and Dionysius and then amalgamate them into a story about a pagan/Jewish hybrid Messiah (who didn't exist) and then turn around and forget he didn't exist and claim he did and that he did so just a few decades earlier is clearly a nonsense hypothesis.

2.  "Jesus was a celestial being who existed in a realm just below the lunar sphere and was not considered an earthly being at all until later."

This is the theory presented by another self-published Mythicist author, Earl Doherty, first in The Jesus Puzzle (2005) and then in Jesus : Neither God nor Man (2009).  Doherty's theory has several main flaws.  Firstly, he claims that this mythic/celestial Jesus was based on a Middle Platonic view of the cosmos that held that there was a "fleshly sub-lunar realm" in the heavens where gods and celestial beings lived and acted out mythic events.  This is the realm, Doherty claims, in which it was believed that Mithras slew the cosmic bull, where Attis lived and died and where Jesus was crucified and rose again.  The problem here is Doherty does very little to back up this claim and, while non-specialist readers may not realise this from the way he presents this idea, it is not something accepted by historians of ancient thought but actually a hypothesis developed entirely by Doherty himself.  He makes it seem like this idea is common knowledge amongst specialists in Middle Platonic philosophy, while never quite spelling out that it's something he's made up. The atheist Biblical scholar Jeffrey Gibson has concluded:

"... the plausibility of D[oherty]'s hypothesis depends on not having good knowledge of ancient philosophy, specifically Middle Platonism. Indeed, it becomes less and less plausible the more one knows of ancient philosophy and, especially, Middle Platonism."

Secondly, Doherty's thesis requires the earliest Christian writings about Jesus, the letters of Paul, to be about this "celestial/mythic Jesus" and not a historical, earthly one.  Except, as has been pointed out above, Paul's letters do contain a great many references to an earthly Jesus that don't fit with Doherty's hypothesis at all.  Doherty has devoted a vast number of words in both his books explaining ways that these references can be read so that his thesis does not collapse, but these are contrived and in places quite fanciful.

Finally, Doherty's explanations as to how this "celestial/mythic Jesus" sect gave rise to a "historical/earthly Jesus" sect and then promptly disappeared without trace strain credulity.  Despite being the original form of Christianity and despite surviving, according to Doherty, well into the Second Century, this celestial Jesus sect vanished without leaving any evidence of its existence behind and was undreamt of until Doherty came along and deduced that it had once existed.  This is very difficult to believe.  Early Christianity was a diverse, divided and quarrelsome faith, with a wide variety of sub-sects, offshoots and "heresies", all arguing with each other and battling for supremacy.  What eventually emerged from this riot of Christianities was a form of "orthodoxy" that had all the elements of Christianity today: the Trinity, Jesus as the divine incarnate, a physical resurrection etc.  But we know of many of the other rivals to this orthodoxy largely thanks to orthodox writings attacking them and refuting their claims and doctrines.  Doherty expects us to believe that despite all these apologetic literature condemning and refuting a wide range of "heresies" there is not one that bothers to even mention this original Christianity that taught Jesus was never on earth at all.  This beggar's belief.

Doherty's thesis is much more popular amongst atheists than the New Age imaginings of "Acharya S" but has had no impact on the academic sphere partly because self-published hobbyist efforts don't get much attention, but mainly because of the flaws noted above.  Doherty and his followers maintain, of course, that it's because of a kind of academic conspiracy, much as Creationists and Holocaust deniers do.

3.  "Jesus began as an allegorical, symbolic figure of the Messiah who got 'historicised' into an actual person despite the fact he never really existed"

This idea has been presented in most detail by another amateur theorist in yet another self-published book: R.G. Price's Jesus - A Very Jewish Myth (2007).  Unlike "Acharya S" and, to a lesser extent Doherty, Price at least takes account of the fact that the Jesus stories and the first members of the Jesus sect are completely and fundamentally Jewish, so fantasies about Egyptian myths or Greek Middle Platonic philosophy are not going to work as points of origin for them.  According to this version of Jesus Mythicism, Jesus was an idealisation of what the Messiah was to be like who got turned into a historical figure largely by mistake and misunderstanding.

Several of the same objections to Doherty's thesis can be made about this one - if this was the case, why are there no remnants of debates with or condemnations of those who believed the earlier version and maintained there was no historical Jesus at all?  And why don't any of Christianity's enemies use the fact that the original Jesus sect didn't believe in a historical Jesus as an argument against the new version of the sect?  Did everyone just forget?

More tellingly, if the Jesus stories arose out of ideas about and expectations of the Messiah, it is very odd that Jesus doesn't fit those expectations better.  Despite Christian claims to the contrary, the first Christians had to work very hard to convince fellow Jews that Jesus was the Messiah precisely because he didn't conform to these expectations. Most importantly, there was absolutely no tradition or Messianic expectation that told of the Messiah being executed and then rising from the dead - this first appears with Christianity and has no Jewish precedent at all.  Far from evolving from established Messianic prophecies and known elements in the scripture, the first Christians had to scramble to find anything at all which looked vaguely like a "prophecy" of this unexpected and highly unMessianic event.

That the centre and climax of the story of Jesus would be based on his shameful execution and death makes no sense if it evolved out of Jewish expectations about the Messiah, since they contained nothing about any such idea.  This climax to the story only makes sense if it actually happened, and then his followers had to find totally new and largely strained and contrived "scriptures" which they then claimed "predicted" this outcome, against all previous expectation.  Price's thesis fails because Jesus' story doesn't conform to Jewish myths enough.

4. "Jesus was not a Jewish preacher at all but was someone else or an amalgam of people combined into one figure in the Christian tradition"

This is the least popular of the Jesus Myth hypotheses, but versions of it are argued by Italian amateur theorist Francesco Carotta (Jesus was Caesar: On the Julian Origin of Christianity. An Investigative Report - 2005)), computer programmer Joseph Atwill (Caesar's Messiah: The Roman Conspiracy to Invent Jesus - 2005) and accountant Daniel Unterbrink (Judas the Galilean: The Flesh and Blood Jesus - 2004).  Carotta claims Jesus was actually Julius Caesar and imposed on Jewish tradition as part of the cult of the Divius Julius.  Atwill claims Jesus was invented by the Emperor Titus and imposed on Judaism in the same way.  Neither do a very good job of substantiating these claims or of explaining why the Romans then turned around, as early as 64 AD (fifteen years before Titus became emperor) and began persecuting the cult they supposedly created.  No scholar takes these theories or that of Unterbrink seriously.

No scholar also argues that Jesus was an amalgam of various Jewish preachers or other figures of the time.  That is because there is nothing in the evidence to indicate this.  This ideas has never been argued in any detailed form by anyone at all, scholar or Jesus myth amateur theorist, but it is something some who don't want to subscribe to the idea that "Jesus Christ" was based on a real person resorts to so that they can put some sceptical distance between the Christian claims and anything or anyone historical.  It seems to be a purely rhetorically-based idea, with no substance and no argument behind it.





So What's the Evidence for the Existence of a Historical Jesus?

Many Christians accept a historical Jesus existed because they never thought to question the idea in the first place or because they are convinced that the gospels can be read as (more or less) historical accounts and so don't need to be seriously doubted on this point.  But why do the overwhelming majority of non-Christian scholars also accept that he existed?

The Total Lack of Evidence for a "Mythic Christianity"

Essentially, it's because it's the most parsimonious explanation of the evidence we have.  Early Christianity, in all its forms, and the critics of early Christianity agree on virtually nothing about Jesus, except for one thing - that he existed as a historical person in the early First Century.  If there really was an original form of Christianity that didn't believe this, as all versions of the "Jesus Myth" idea require, then it makes no sense that there is no trace of it.  Such an idea would be a boon to the various Gnostic branches of Christianity, which emphasised his spiritual/mystical aspects and saw him as an emissary from a purely spiritual world to help us escape the physical dimension.  A totally non-historical, purely mystical Jesus would have suited their purposes perfectly.  Yet they never taught such a Jesus - they always depict him as a historical First Century teacher, but argue that he was "pure spirit" and only had the "illusion of flesh".  Why?  Because they couldn't deny that he had existed as a historical person and there was no prior "mythic Jesus" tradition for them to draw on.

Similarly, the memory of an earlier, original Christianity which didn't believe in a historical Jesus would have been a killer argument for the many Jewish and pagan critics of Christianity.  Jesus Mythicists claim this mythic Jesus Christianity survived well into the Second or even Third Century.  We have orthodox Christian responses to critiques by Jews and pagans from that period, by Justin Martyr, Origen and Minucius Felix.  They try to confront and answer the arguments their critics make about Jesus - that he was a fool, a magician, a bastard son of a Roman soldier, a fraud etc - but none of these apologetic works mention so much as a hint that anyone ever claimed he never existed.  If a whole branch of Christianity existed that claimed just this, why did it pass totally unnoticed by these critics? Clearly no such earlier "mythic Jesus" proto-Christianity existed - it is a creation of the modern Jesus Mythicist activists to prop up their theory.

Indicators of Historicity in the Gospels

The main reason non-Christian scholars accept that there was a Jewish preacher as the point of origin of the Jesus story is that the stories themselves contain elements which only make sense if they were originally about such a preacher but which the gospel writers themselves found somewhat awkward.  As noted above, far from conforming closely to expectations about the coming Messiah, the Jesus story actually shows many signs of being shoehorned into such expectations and not exactly fitting very well.

For example, in gMark Jesus is depicted as going to the Jordan and being baptised by John the Baptist (Mark 1: 9-11), after which he hears a voice from heaven and goes off into the wilderness to fast.  For the writer of gMark, this is the point where Jesus becomes the Messiah of Yahweh and so there is no problem with him having his sins washed away by John, since prior to his point he was man like any other.  The writer of gMatthew, however, has a very different Christology.  In his version, Jesus has been the ordained Messiah since his miraculous conception, so it is awkward for him to have the chosen one of God going to be baptised by John, who is a lesser prophet.  So gMatthew tells more or less the same story as he finds in gMark, which he uses as his source, but adds a small exchange of dialogue not found in the earlier version:

But John tried to deter him, saying, “I need to be baptized by you, and do you come to me?”
Jesus replied, Let it be so now; it is proper for us to do this to fulfill all righteousness. Then John consented.
(Matt 3:14-15)

When we turn to the latest of the gospels, gJohn, we find a very different story again.  The writer of this gospel depicts Jesus as being a mystical, pre-existent Messiah who had a heavenly existence since the beginning of time.  So for him the idea of Jesus being baptised by John is even more awkward.  So he solves the problem by removing the baptism altogether.  In this latest version, John is baptising other people and telling them that the Messiah was to come and then sees Jesus and declares him to be the Messiah (John 1:29-33).  There is no baptism of Jesus at all in the gJohn version.

So in these three examples we have three different versions of the same story written at three times in the early decades of Christianity.  All of them are dealing with the baptism of Jesus by John in different ways and trying to make it fit with their conceptions of Jesus and at least two of them are having some trouble doing so and are having to change the story to make it fit their ideas about Jesus.  All this indicates that the baptism of Jesus by John was a historical event and known to be such and so could not be left out of the story.  This left the later gospel writers with the problem of trying to make it fit their evolving ideas about who and what Jesus was.

There are several other elements in the gospels like this.  gLuke and gMatthew go to great lengths to tell stories which "explain" how Jesus came to be born in Bethlehem despite being from Nazareth, since Micah 5:2 was taken to be a prophecy that the Messiah was to be from Bethlehem.  Both gospels, however, tell completely different, totally contradictory and mutually exclusive stories (one is even set ten years after the other) which all but the most conservative Christian scholars acknowledge to be non-historical.  The question then arises: why did they go to this effort?  If Jesus existed and was from Nazareth, this makes sense.  Clearly some Jews objected to the claim Jesus was the Messiah on the grounds that he was from the insignificant village of Nazareth in Galilee and not from Bethlehem in Judea - John 7:41-42 even depicts some Jews making precisely this objection.  So it makes sense that Christian traditions would arise that "explain" how a man known to be a Galilean from Nazareth came to be born in Bethlehem and raised in Nazareth - thus the contradictory stories in gLuke and gMatthew that have this as their end.

If, however, there was no historical Jesus then it is very hard to explain why an insignificant town like Nazareth is in the story at all.  If Jesus was a purely mythic figure and the stories of his life evolved out of expectations about the Messiah then he would be from Bethlehem, as was expected as a Messiah.  So why is Nazareth, a tiny place of no religious significance, in the story?  And why all the effort to get Jesus born in Bethlehem but keep Nazareth in the narrative?  The only reasonable explanation is that it's Nazareth that is the historical element in these accounts - it is in the story because that is where he was from.  A historical Jesus explains the evidence far better than any "mythic" alternative.   





"Alexamenos worships his god" - A Roman graffito mocks the idea of a crucified god

But probably the best example of an element in the story which was so awkward for the early Christians that it simply has to be historical is the crucifixion. The idea of a Messiah who dies was totally unheard of and utterly alien to any Jewish tradition prior to the beginning of Christianity, but the idea of a Messiah who was crucified was not only bizarre, it was absurd.  According to Jewish tradition, anyone who was "hanged on a tree" was to be considered accursed by Yahweh and this was one of the reasons crucifixion was considered particularly abhorrent to Jews.  The concept of a crucified Messiah, therefore, was totally bizarre and absurd.

It was equally weird to non-Jews.  Crucifixion was considered the most shameful and abhorrent of deaths, so much so that one of the privileges of Roman citizenship is that citizens could never be crucified.  The idea of a crucified god, therefore, was absurd and bizarre. This was so much the case that the early Christians avoided any depictions of Jesus on the cross - the first depictions of the Crucifixion appear in the Fourth Century, after Christian emperors banned crucifixion and it began to lose its stigma.  It's significant that the earliest depiction of the crucifixion of Jesus that we have is a graffito from Rome showing a man worshipping a crucified figure with the head of a donkey with the mocking caption "Alexamenos worships his god".  The idea of a crucified god was, quite literally, ridiculous.  Paul acknowledges how absurd the idea of a crucified Messiah was in 1Cor 1:23, where he says it "is a stumbling block to the Jews and an absurdity to the gentiles".

The accounts of Jesus' crucifixion in the gospels also show how awkward the nature of their Messiah's death was for the earliest Christians.  They are all full of references to texts in the Old Testament as ways of demonstrating that, far from being an absurdity, this was what was supposed to happen to the Messiah.  But none of the texts used were considered prophecies of the Messiah before Christianity came along and some of them are highly forced.  The "suffering servant" passages in Isaiah 53 are pressed into service as "prophecies" of the crucifixion, since they depict a figure being falsely accused, rejected and given up to be "pierced .... as a guilt offering".  But the gospels don't reference other parts of the same passage which don't fit their story at all, such as where it is said this figure will "prolong his days and look upon his offspring".

Clearly the gospel writers were going to some effort to find some kind of scriptural basis for this rather awkward death for their group's leader, one that let them maintain their belief that he was the Messiah.  Again, this makes most sense if there was a historical Jesus and he was crucified, leaving his followers with this awkward problem.  If there was no historical Jesus at all, it becomes very difficult to explain where this bizarre, unprecedented and awkwardly inconvenient element in the story comes from.  It's hard to see why anyone would invent the idea of a crucified Messiah and create these problems.  And given that there was no precedent for a crucified Messiah, it's almost impossible to see this idea evolving out of earlier Jewish traditions.  The most logical explanation is that it's in the story, despite its vast awkwardness, because it happened.

Non-Christian References to Jesus as Historical Figure

Many Christian apologists vastly overstate the number of ancient non-Christian writers who attest to the existence of Jesus.  This is partly because they are not simply showing that a mere Jewish preacher existed, but are arguing for the existence of the "Jesus Christ" of Christian doctrine: a supposedly supernatural figure who allegedly performed amazing public miracles in front of audiences of thousands of witnesses.  It could certainly be argued that such a wondrous figure would have been noticed outside of Galilee and Judea and so should have been widely noted as well.  So Christian apologists often cite a long list of writers who mention Jesus, usually including Josephus, Pliny the Younger, Tacitus, Suetonius, Lucian, Thallus and several others.  But of these only Tacitus and Josephus actually mention Jesus as a historical person - the others are all simply references to early Christianity, some of which mention the "Christ" that was the focus of its worship.

If we are simply noting the existence of Jesus as a human Jewish preacher, we are not required to produce more mentions of him than we would expect of comparable figures.  And what we find is that we have about as much evidence for his existence (outside any Christian writings) as we have for other Jewish preachers, prophets and Messianic claimants of the time.  The two non-Christian writers who mention him as a historical person are Josephus and Tacitus.

Josephus

The Jewish priestly aristocrat Joseph ben Matityahu, who took the Roman name Flavius Josephus, is our main source of information about Jewish affairs in this period and is usually the only writer of the time who makes any mention of Jewish preachers, prophets and Messianic claimants of the First Century.  Not surprisingly, he mentions Jesus twice: firstly in some detail in Antiquities of the Jews XVIII.3.4 and again more briefly when mentioning the execution of Jesus' brother James in Antiquities XX.9.1.  The first reference is problematic, however, as it contains elements which Josephus cannot have written and which seem to have been added later by a Christian interpolator.  Here is the text, with the likely interpolations in bold:

"Now there was about this time Jesus, a wise man, if it be lawful to call him a man; for he was a doer of paradoxical deeds, a teacher of such men as receive the truth with pleasure. He drew over to him both many of the Jews and many of the Gentiles. He was [the] Christ And when Pilate at the suggestion of the principal men amongst us, had condemned him to the cross, those that loved him at the first did not forsake him; for he appeared to them alive again the third day; as the divine prophets had foretold these and ten thousand other wonderful things concerning him. And the tribe of Christians, so named from him, are not extinct at this day."

There has been a long debate about what parts of this reference to Jesus are authentic to Josephus or even if the whole passage is a wholesale interpolation.  Proponents of the Jesus Myth hypothesis, naturally, opt for the idea that it is not authentic in any way, but there are strong indications that, apart from the obvious additions shown in bold above, Josephus did mention Jesus at this point in his text.

To begin with, several elements in the passage are distinctively Josephan in their style and phrasing.  "Now (there was) about this time ..." is used by Josephus as a way of introducing a new topic hundreds of times in his work.  There are no early Christian parallels that refer to Jesus merely as "a wise man", but this is a term used by Josephus several times, eg about Solomon and Daniel.  Christian writers placed a lot of emphasis on Jesus' miracles, but here the passage uses a fairly neutral term παραδόξων ἔργων - "paradoxa erga" or "paradoxical deeds".  Josephus does use this phrase elsewhere about the miracles of Elisha, but the term can also mean "deeds that are difficult to interpret" and even has overtones of cautious scepticism.  Finally, the use of the word φῦλον ("phylon" - "race, tribe") is not used by Christians about themselves in any works of the time, but is used by Josephus elsewhere about nations or other distinct groups.  Additionally, with the sole exception of Χριστιανῶν ("Christianon" - "Christians") every single word in the passage can be found elsewhere in Josephus' writings.

The weight of the evidence of the vocabulary and style of the passage is heavily towards its partial authenticity.  Not only does it contain distinctive phrases of Josephus that he used in similar contexts elsewhere, but these are also phrases not found in early Christian texts.  And it is significantly free of terms and phrases from the gospels, which we'd expect to find if it was created wholesale by a Christian writer.  So either a very clever Christian interpolator somehow managed to immerse himself in Josephus' phrasing and language, without modern concordances and dictionaries and create a passage containing distinctively Josephean phraseology, or what we have here is a genuinely Josephean passage that has simply been added to rather clumsily.

As a result of this and other evidence (eg the Arabic and Syriac paraphrases of this passage which seem to come from a version before the clumsy additions by the interpolator) the consensus amongst scholars of all backgrounds is that the passage is partially genuine, simply added in a few obvious places.  Louis H. Feldman's Josephus and Modern Scholarship (1984) surveys scholarship on the question from 1937 to 1980 and finds of 52 scholars on the subject, 39 considered the passage to be partially authentic. 

Peter Kirby has done a survey of the literature since and found that this trend has increased in recent years.  He concludes "In my own reading of thirteen books since 1980 that touch upon the passage, ten out of thirteen argue the (Antiquities of the Jews XVIII.3.4 passage) to be partly genuine, while the other three maintain it to be entirely spurious. Coincidentally, the same three books also argue that Jesus did not exist." 

The other mention of Jesus in Josephus, Antiquities XX.9.1, is much more straightforward, but much more of a problem for Jesus Mythicists.  In it Josephus recounts a major political event that happened when he was a young man.  This would have been a significant and memorable event for him, since he was only 25 at the time and it caused upheaval in his own social and political class, the priestly families of Jerusalem that included his own.

In 62 AD the Roman procurator of Judea, Porcius Festus, died while in office and his replacement, Lucceius Albinus, was still on his way to Judea from Rome.  This left the High Priest, Hanan ben Hanan (usually called Ananus), with a freer reign than usual. Ananus executed some Jews without Roman permission and, when this was brought to the attention of the Romans, Ananus was deposed.  This deposition would have been memorable for the young Josephus, who had just returned from an embassy to Rome on the behalf of the Jerusalem priests.  But what makes this passage relevant is what Josephus mentions, in passing, as the cause of the political upheaval:

Festus was now dead, and Albinus was but upon the road; so (the High Priest) assembled the Sanhedrin of judges, and brought before them the brother of Jesus, who was called Messiah, whose name was James, and some others; and when he had formed an accusation against them as breakers of the law, he delivered them to be stoned.

This mention is peripheral to the story Josephus is telling, but since we know from Christian sources that Jesus' brother James led the Jesus sect in Jerusalem in this period and we have a separate, non-dependent, Christian account of James' execution by the Jerusalem priesthood, it is fairly clear which "Jesus who was called Messiah" Josephus is referring to here.

Almost without exception, modern scholars consider this passage genuine and an undisputed reference to Jesus as a historical figure by someone who was a contemporary of his brother and who knew of the execution of that brother first hand.  This rather unequivocal reference to a historical Jesus leaves Jesus Mythicists with a thorny problem, which they generally try to solve one of two ways:

(i) "The words "who was called Messiah" are a later Christian interpolation" -

Since it is wholly unlikely that a Christian interpolator invented the whole story of the deposition of the High Priest just to slip in this passing reference to Jesus, Mythicists try to argue that the key words which identify which Jesus is being spoken of are interpolated.  Unfortunately this argument does not work.  This is because the passage is discussed no less than three times in mid-Third Century works by the Christian apologist Origen and he directly quotes the relevant section with the words "Jesus who was called the Messiah" all three times: in Contra Celsum I.4, in Contra Celsum II:13 and in Commentarium in evangelium Matthaei X.17.  Each time he uses precisely the phrase we find in Josephus: αδελφος Ιησου του λεγομενου Χριστου ("the brother of that Jesus who was called Messiah").  This is significant because Origen was writing a whole generation before Christianity was in any kind of position to be tampering with texts of Josephus.  If this phrase was in the passage in Origen's time, then it was clearly original to Josephus.

(ii) "The Jesus being referred to here was not the Jesus of Christianity, but the 'Jesus, son of Dameus' mentioned later in the same passage."

After detailing the deposition of the High Priest Ananus, Josephus mentions that he was succeeded as High Priest by a certain "Jesus, son of Damneus".  So Mythicists try to argue that this was the Jesus that Josephus was talking about earlier, since Jesus was a very common name.  It certainly was, but we know how Josephus was careful to differentiate between different people with the same common first name.  So it makes more sense that he calls one "Jesus who was called Messiah" and the other "Jesus son of Damneus" to do precisely this.  Nowhere else does he call the same person two different things in the same passage, as the Mythicist argument requires.  And he certainly would not do so without making it clear that the Jesus who was made HIgh Priest was the same he had mentioned earlier, which he does not do.



The idea that the Jesus referred to as the brother of James was the later mentioned "Jesus son of Damneus" is further undercut by the narrative in the rest of Book XX.  In it the former high priest Ananus continues to play politics and curries favour with the Roman procurator Albinus and the new high priest by giving them rich presents.  This makes no sense if Jesus the brother of the executed James was also "Jesus the son of Damneus", since the new high priest in question is the same Jesus ben Damneus - the idea that he would become friends with his brother's killer just because he was given some nice gifts is ridiculous.

Mythicists are also still stuck with the phrase "who was called Messiah", which Origen's mentions show can't be dismissed as an interpolation.  They usually attempt to argue that, as a High Priest, Jesus the son of Damenus would have been "called Messiah" because "Messiah" means 'anointed" and priests were anointed with oil at their elevation.  Since there are no actual examples of any priests being referred to this way, this is another ad hoc argument designed merely to get the Mythicist argument off the hook.

So the consensus of scholars, Christian and non-Christian, is that the Antiquities XVIII.3.4 passage is authentic despite some obvious later additions and the Antiquities XX.9.1 passage is wholly authentic.  These references alone give us about as much evidence for the existence of a historical "Jesus, who was called Messiah" as we have for comparable Jewish preachers and prophets and is actually sufficient to confirm his existence with reference to any gospel or Christian source.

Tacitus

The mention of Jesus in the Annals of the aristocratic Roman historian and senator Publius Cornelius Tacitus is significant partly because of his status as one of the most careful and sceptical historians of the ancient world and partly because it is from what is obviously a hostile witness.  Tacitus absolutely despised Christianity, as he make clear when he mentions how the emperor Nero tried to scapegoat them after the Great Fire of Rome in 64 AD.  He also gives an account to his readers as the origin of the Christian sect and their founder in Judea:

Consequently, to get rid of the report, Nero fastened the guilt and inflicted the most exquisite tortures on a class hated for their abominations, called Christians by the populace. Christus, from whom the name had its origin, suffered the extreme penalty during the reign of Tiberius at the hands of one of our procurators, Pontius Pilatus, and a most mischievous superstition, thus checked for the moment, again broke out not only in Judæa, the first source of the evil, but even in Rome, where all things hideous and shameful from every part of the world find their centre and become popular.
(Tacitus, Annals, XV.44)

Again, this clear reference to Jesus, complete with the details of his execution by Pilate, is a major problem for the Mythicists.  They sometimes try to deal with it using their old standby argument: a claim that it is a later interpolation.  But this passage is distinctively Tacitean in its language and style and it is hard to see how a later Christian scribe could have managed to affect perfect Second Century Latin grammar and an authentic Tacitean style and fool about 400 years worth of Tacitus scholars, who all regard this passage and clearly genuine.

A more common way of dismissing this passage is to claim that all Tacitus is doing is repeating what Christians had told him about their founder and so it is not independent testimony for Jesus at all.  This is slightly more feasible, but still fails on several fronts.

Firstly, Tacitus made a point of not using hearsay, of referring to sources or people whose testimony he trusted and of noting mere rumour, gossip or second-hand reports as such when he could.  He was explicit in his rejection of history based on hearsay earlier in his work:

My object in mentioning and refuting this story is, by a conspicuous example, to put down hearsay, and to request that all those into whose hands my work shall come not to catch eagerly at wild and improbable rumours in preference to genuine history. 
(Tacitus, Annals, IV.11)

Secondly, if Tacitus were to break his own rule and accept hearsay about the founder of Christianity, then it's highly unlikely that he would do so from Christians themselves (if this aristocrat even had any contact with any), who he regarded with utter contempt.  He calls Christianity "a most mischievous superstition .... evil .... hideous and shameful .... (with a) hatred against mankind" - not exactly the words of a man who regarded its followers as reliable sources about their sect's founder.

Furthermore, what he says about Jesus does not show any sign of having its origin in what a Christian would say: it has no hint or mention of Jesus' teaching, his miracles and nothing about the claim he rose from the dead.  On the other hand, it does contain elements that would have been of note to a Roman or other non-Christian: that this founder was executed, where this happened, when it occurred {"during the reign of Tiberius") and which Roman governor carried out the penalty.

We know from earlier in the same passage that Tacitus consulted several (unnamed) earlier sources when writing his account of the aftermath of the Great Fire (see Annals XV.38), so it may have been one of these that gave him his information about Jesus.  But there was someone else in Rome at the time Tacitus wrote who mixed in the same circles, who was also a historian and who would have been the obvious person for Tacitus to ask about obscure Jewish preachers and their sects.  None other than Josephus was living and writing in Rome at this time and, like Tacitus, associated with the Imperial court thanks to his patronage first by the emperor Vespasian and then by his son and successor Titus.  There is a strong correspondence between the details about Jesus in Annals XV.44 and Antiquities XVIII.3.4, so it is at least quite plausible that Tacitus simply asked his fellow aristocratic scholar about the origins of this Jewish sect.

Conclusion

The question asked if historians regarded the existence of Jesus to be "historical fact".  The answer is that they do as much as any scholar can do so for the existence of an obscure peasant preacher in the ancient world.  There is as much, if not slightly more, evidence for the existence of Yeshua ben Yusef as there is for other comparable Jewish preachers, prophets and Messianic claimants, even without looking at the gospel material.  Additionally, that material contains elements which only make sense if their stories are about a historical figure. 

The arguments of the Jesus Mythicists, on the other hand, require contortions and suppositions that simply do not stand up to Occam's Razor  and continually rest on positions that are not accepted by the majority of even non-Christian and Jewish scholars.  The proponents of the Jesus Myth hypothesis are almost exclusively amateurs with an ideological axe to grind and their position is and will almost certainly remain on the outer fringe of theories about the origins of Christianity.