[Image] Uni of Washington Alexander Wynne has been at the forefront of apologetics for taking the suttas at face value as historically accurate. He recently uploaded a copy of his 2005 article, The Historical Authenticity of Early Buddhist Literature, to academia.edu:
(2005) The Historical Authenticity of Early Buddhist Literature: A Critical Evaluation. Vienna Journal of South Asian Studies. 49: 35-70
Readers may know that there is a split in Buddhist studies. On one side are religious traditionalists and mainly British scholars (particularly Richard Gombrich and Wynne at Oxford) who see the early Buddhist texts as a more or less accurate account of Buddhist history. On the other side are religious sceptics (yours truly) and mainly American scholars (particularly Greg Schopen and Don Lopez) who don't think there is anything authentically historical in the suttas.
Wynne writes and argues well and is taking an active role in the debate. But he is far less critical than he ought to be of his sources and it's only by ignoring many of the problems that I'll set out below that he can stick to his conclusions. He places too much credence on the traditional narratives of Buddhism. 
We know this: there is a body of literature we associate with early Buddhism and the early phase of sectarian Buddhism. This literature is preserved, in a language we now call Pali, in major collections of manuscripts in Sri Lanka, Burma and Thailand, with minor collections in Laos, Vietnam and perhaps other places. Substantial parts of several other recensions are preserved in Middle-Chinese in China, Japan and Korea (the most influential modern edition of the Chinese Canon, the Taishō, is based on a recension preserved in Korean) both in manuscript form and in printed editions. Fragments of several recensions are preserved in Gāndhārī, Buddhist Sanskrit, and Tibetan collections.

There are clearly relationships between these recensions of the literature. Many of the actual sutta/sūtra texts are same or similar, though some are quite different. However at the level of Nikāya/Āgama collections, they only partially overlap. Even within the Pāḷi Nikāyas when a sutta is recorded twice in two different Nikāyas it is often different in significant ways. Similarly the various collections titled Vinaya only partially overlap (and to a lesser extent than the sūtras). The Abhidharma collections are all very different and even adopt different hermeneutic principles for interpreting the texts. Thus the collections seem to draw on a common body of texts, but to collate and interpret them differently. 
Scholars in favour of seeing this body of literature as "authentic" (a word we'll have to come back to and define) tend to portray the literature as fairly homogeneous and belonging to a specific region in space and time. They tend to accept the story told by the literature about it's own genesis. I find the reasons for doing so less and less convincing the more I read the literature. 

Dates
Here's the thing about dating. We can be reasonable certain about the date of Asoka because of his inscriptions. Mid 3rd century BC. All of the dates for Indian history in the first millennia BC are worked out (mostly guessed at) with respect to this single reference point. We assume that literature which does not know Asoka, was written before his time. The Pali Nikāyas and Vināya do not know Asoka. What's more they seem to describe a landscape of fortified cities and petty kings in which the later hegemons like the Kingdom of Magadha are just starting to flex their imperialistic muscles. Not only is there no sign of Asoka, there's no sign of the Mauryan dynast, Candragupta. The Magadhan capital is still Rājagṛha rather than Pāṭaliputta. Archaeology tells us that this form of geography began to emerge ca. 6th century BC. We've rediscovered ruins that correspond to the major civil and geographic reference points that seem to align with the Buddhist stories. The major exception of the on-going dispute over the location of Kapilavastu. If, as I suspect, the story of the Buddha's life is largely a later fiction, then the identity home town is also likely to be fictional - Kapilavastu is likely to have been a wattle & daub village. 
Given these points we assume that the early Buddhist texts were composed between ca. 6th-4th century BC. There is no way to date the texts absolutely. The oldest Buddhists texts are birch bark scrolls from Gandhāra dated roughly to the first century AD. The oldest Pāli text is a metal plate from the 6th century, most of the manuscripts of the Pāli Canon are only a century or two old. We know from their texts that Brahmins of a slightly earlier period (associated with the exegetical Brāhmaṇa literature) thought the region the Buddha lived in was barbaric and an unsuitable place for Brahmins to live. None of the early Upaniṣads mention Buddhists and whereas Brahmins feature quite prominently in the early Buddhist texts. Many scholars think we can see hints at some knowledge of themes from the Upaniṣads in the early Buddhist texts. One major scholar, Johannes Bronkhorst, inverts this however and argues that the Upaniṣads must have been composed after the early Buddhist texts. Brahmins took some time to fully convert the central and eastern Ganges plain to their culture. In fact this happened after Asoka. But the early Buddhist texts record fairly frequent meetings with Brahmins and interesting phenomena like land grants by kings to Brahmins (where land = income). Buddhist texts also give a scattered, but overall fairly comprehensive, picture of the Brahmanical religion revolving around sacrificial fires and strong guru/disciple relationships. 
We don't know and cannot know if this is correct. The assumption by Gombrich and Wynn is that if the texts say something is so and we have no reason to doubt them, then we ought to take the texts as being accurate. I and others argue that we have every reason to doubt the texts and should never take them at their word, but should interrogate them to expose inconsistencies.
One of the major problems is that while these cities are known to exist and archaeological evidence for Buddhist activity is found in and around them, it all dates from many centuries after the period when we assume the Buddha to have lived. There's no clearly Buddhist archaeology that pre-dates Asoka. Given Buddhist's own stories this is quite surprising - we know for example that land was donated and structures created by rich followers. But all the structures discovered to date are from the period of Asoka or later. Attempts to interpret pre-Asokan dates are often obviously bogus.
Another problem is that by their own admission the texts were preserved orally for something like three centuries before being written down in Sri Lanka, ca. 100 BC. We don't know (I think) when the texts were written down in India. However we do have manuscripts of Buddhist texts from about the 1st century AD from Gandhāra, so at least by that point Buddhist texts were written. In some cases it's obvious from internal evidence that the texts were composed well after the period they purport to be an account of. Comparison of little details in the Chinese Canon suggests that it was closed to additions and emendation somewhat later than the Pali Canon, which perhaps suggests a later date for being committed to writing. This is a lot of conjecture however, and none of it testable with the present state of archaeology and paleography.

The texts represent an event horizon beyond which we cannot see much if anything with clarity. All dates, except Asoka are vague and/or speculative, if only because establishing relationships to Asoka is often an exercise in speculation. Any historical facts are smeared out and information is lost. We can say what kind of world is reflected in the texts, but we have a great deal of difficulty demonstrating a relationship between this story and reality. Contra Gombrich and Wynne I think we have every reason to doubt traditional narratives.


Cracks
My own recent work has been focussed on cracks in the facade of homogeneity and unanimity presented by many scholars. In particular I've tried to show that the idea that the Pali Canon represents a single tradition is not sustainable. The Pali texts are clearly collated from multiple oral lineages that have been inexpertly edited into several collections (nikāyas). Supposedly fundamental doctrines show a bewildering amount of diversity in the suttas. Details are often fudged or changed. And the approach to this by scholars has been to compose unifying narratives that gloss over internal inconsistency or try to demonstrate a linear development within the texts. I think this methodology is flawed from the start. Instead, I argue that it is precisely the flaws in our material that convey the most information about the history of the collection. We ought to be foregrounding flaws rather than explaining them away. And we have to consider that linear developments do not explain the divergences sufficiently well. 
My work on the Buddha's name for example shows that Siddhartha is a name attributed long after the time of Canon, and that if his family used a gotra name they used it extremely idiosyncratically and ahistorically (See What's in a Name pdf). If the head of the family was alive, he (i.e. Suddhodana) rather than his son ought to have been called Gautama. His son ought to have been Gautamaputra,  Gautamya, or some other diminutive (though of course they certainly did not speak or use Sanskrit!). On the other hand why were his mother and aunt called Gautamī? Gotras are exogamous marriage groups: Māyā and Prajāpati wouldn't have changed their gotra names on marriage, and nor could they have married within the Gautama gotra. And why are there so few other members of the Gautama clan in the Pāli? Other gotra names occur frequently. Gotra names are a tradition belonging to the strongly patriarchal Brahmins, though matrilineal names are not unknown, it's unlikely that the Buddha took his mother's gotra name (the matrilineal form Gautamiputra occurs in non-Buddhist contexts). Gautama is a gotra of considerable renown in the Vedic world. The patriarch, Gotama, was one of the poets who composed the Ṛgveda, and his descendents, the Gautamas, feature prominently as teachers and exegetes.  And yet the Śākyas were clearly not part of the Vedic milieu and at times the Buddha is portrayed as treating the Brahmins as crazy foreigners. The ascription of Brahmanical caste identity to the Buddha is almost certainly anachronistic, not to mention being somewhat variable. Though he is usually a Gautama, at least once he is said to be from the Āditya gotra. The Buddha's biography has been reworked to give him prestige in a Brahmin dominated world. This tells us that the biography was probably composed in a time of Brahmanical hegemony, which would place it after Asoka. And it happened in a way that was accepted and recorded by all Buddhists. This fact contradicts all other theories about the time period that the texts represent.
I've also discussed the contradictory biographical traditions in the suttas (see The Buddha's Biography). There are at least two biographies of the Buddha. In one he is a unmarried youth when he leaves home and his mother is still alive. In another he is a man of 29 whose mother died in childbirth. The youth is found in the Pāli version of the Ariyapariyesana Sutta and the 29 year old in the Chinese counterpart of the same text. Both stories cannot be true and we have no objective way of knowing which is. All we have is a general historical principle that Buddhist stories become more elaborate over time (there is clear evidence of this in the accurately dated Chinese translations). Thus, we usually assume that a less elaborate version of a story is (relatively) earlier than the same story in a more elaborate version. 

Ambiguity
Thus the suttas are at best an ambiguous source of information. Sometimes consistent with an early period centred on the 5th century BCE and yet at other times with a period some centuries after this. Many details of history found in the Canon are also contradicted in the Canon. This lack of internal consistency is not simply overlooked or explained away, it is presented as the opposite, as strikingly self-consistent. For the average Buddhist, almost inevitably falling into confirmation bias, the endorsement of their views by scholars of considerable reputation makes it all the harder to objectively evaluate the information at our disposal. 
The situation is probably that the suttas do not represent one period of history, but were composed over several centuries and that earlier texts form a template for later texts. Everything we know about later Buddhist texts, such as the Perfection of Wisdom texts, tells us that Indian Buddhists never stopped retelling and embellishing their stories. This is clear for example where we have multiple Chinese translations over the centuries: later translations of the same text are inevitably longer and more elaborate, often accumulating several chapters at a time. My observation of comparing Chinese and Pali texts is that this happened to a lesser extent with early Buddhist texts as well (see my translations and notes on the Chinese Spiral Path texts). 
However, we also know that words, phrases, sentences, paragraphs and sometimes even whole texts were recycled time and again. It's usually impossible to know which was the first use of any repeating unit. The end result is that suttas are frequently formulaic and repetitive. Many "suttas" are merely fragments of larger units. This would seem to fit a situation in which a relatively small number of texts were expanded and elaborated by story tellers who both used standard vocabulary and themes, and embellished stories as they saw fit. Versions of the stories diverged, sometimes to the point of seeming like a distinct story though usually with the same characters in the same setting.
In support of this is the surprising ambiguity in the technical vocabulary of Buddhism. All too often key terms are vaguely defined, ambiguous, or simply confused. Important words seem to be unhelpfully defined in multiple ways, so that each time the word appears one must pause and consider the context in order to understand. Important basic terms like dharma, vijñāna, and nāmarūpa fit this pattern. If this tradition traces back to a single person, then he was a far from being a philosophical genius. Rather the confusion in terminology argues against a founder figure who defined a jargon. It argues for a jargon that drew on many external sources and developed over time, often in independent groups, and was then roughly pulled together by some encyclopedist urge of the kind we often associate with empires. This may point to the reign of Asoka as a time when Buddhism first coalesced from a number of small, scattered, independent religious communities into a more systematic religion. On the other hand the existence of multiple recensions of the Canon argues for unevenness even in the process of consolidation. The sheer scale of the material that had been produced at this point defeated attempts to organise it into an homogeneous collection. What's more, probably quite quickly, at least two competing collections were created in different languages including Gāndhārī and Sanskrit. Gāndhārī was an important regional dialect; while Sanskrit is the prestige language of the Brahmins that did not come into widespread use until the Brahmin hegemony was well established and Sanskrit the language of the royal courts. However Gandhāra was also a centre for Sanskrit study and learning, being the home of Pāṇini, the most famous grammarian in Indian (and world) history.
It's not simply words that are confused in the suttas. There is the fundamental incompatibility of karma and pratītyasamutpāda. The former demands effects long after conditions have ceased, and the latter forbids it. Karma in the suttas is eternalistic by the standards of the suttas themselves (a point which Nāgārjuna notices even if modern scholars do not); while pratītyasamutpāda would prevent karma from working at all. I've outlined a few of the approaches that emerged to deal this problem in the Abhidharma period and after. Such fundamental metaphysical problems have been routinely ignored in Buddhist studies. The situation is analogous to the problem of skewed reporting in drug trials. Studies sponsored by drug companies have tended to only publish results when the results were positive. If a new drug scored badly, the research was simply not published. In this case meta-analysis would show an overall benefit. This has been particularly true, for example, for antidepressant medications. Many such medications are no better than placebo on average (and sometimes worse) when you take into account unpublished negative studies. While some work has been done comparing sectarian thinking, it seems to gloss over the problems they were trying to solve when they came up with their different ideas. 
Buddhist scholars seem loath to be critical of Buddhism. I notice the same phenomenon in Indian Philosophy generally: the field is still descriptive rather than critical. We don't go looking for major problems of the kind that I have outlined. We tend to cite previous descriptive work that has meticulously ironed out problems in our primary sources as proof of the overall coherence of Buddhist teaching. But even the first sectarian Buddhists did not find the metaphysics of early Buddhism coherent and invented new doctrines to deal with various problems. Written records of sectarian conflict on this issue emerged probably before the first millennium. And yet the question of why Buddhists felt the need to further explain their own doctrines and to argue quite so much as they did between schools of thought seems to be somehow underplayed. As though these ancient intellectual battles are of no contemporary interest. To my mind they are absolutely crucial to understanding the history of Buddhism.

Was the Buddha a Poor Philosopher?
An over-arching question here is: Was the Buddha a poor philosopher who could not articulate a coherent system of thought, even with the restrictions that he himself placed on epistemology? Was he like many of his contemporary disciples an anti-rationalist dedicated to subverting reasoned discussion? Or was the Buddhist tradition a syncretic mishmash from the beginning, in search of unifying narratives (like Siddhartha Gotama) from the beginning and only really finding sufficient coherence after some centuries had passed? Or is there some better answer to the philosophical mess we find in the suttas? 

To me Buddhism makes more sense if the story of the Buddha marks the culmination of a process of assimilating a wide range of cultural influences that is a new synthesis of religious ideas in India. In this we see the same kind of pattern in the advent of Tantra in the 6th century CE. Tantra is a grand synthesis of religious ideas, attitudes and practices that revitalising Indian religion, but older religious ideas are also conserved and propagated alongside. I argue that something like the Tantric synthesis happened in Indian in the 6th - 4th centuries BC, and that it took a long time for doctrines and narratives to settle into the familiar patterns. 
So where does this leave those of us who want to use the suttas as historical sources? It leaves us in a metaphorical minefield. There seem to be two main responses: smooth over and ignore the inconsistencies, or highlight and focus on them. The former argues that, at least to some extent the suttas are history. The latter that there is no history. Some straddle this divide. For example Anālayo has written cogently about the nature of oral traditions. Overall however I'm arguing for a change in method and a revision of all of what has passed for history to date.


Authenticity

I think the facts speak for themselves as long as we consider all of them. I said at the beginning that we would have to address the question of what authenticity means. In fact given the complexity of the problem I doubt a single definition of authenticity would suffice. The question is always authentic with reference to what? Is the Theravāda canon any more (or less) authentic than the other recensions just because by accident of history it survived seemingly intact?  Doesn't the massive amount of internal contradiction cast doubt on authenticity? Apparently for many scholars and traditionalists it does not. If the texts are an authentic record, then what are they an authentic record of? And more importantly when?

If the texts are written down centuries after the time they purport to represent, then are they authentic? Are the Pāḷi texts as authentic as history as, say Shakespeare? We presume they were composed orally and transmitted verbally for some centuries. Probably something like 12-15 generations passed if current guesses for the dates of the Buddha and the dates of writing are correct. There's no evidence that Buddhists used the mnemonic techniques that Brahmins used to accurately record the Vedas. It's just an oral literature passed on from generation to generation.

The different collections seem to reflect separate periods of relatively localised consolidation and stability after periods of sectarian diversity. In other words what precedes the period of canonisation is not unity, but diversity and conflict. What encourages us to think in terms of a big bang is the clearly fictional story of a founder. That story is clearly based in a period in which Brahmanical values are hegemonic, most likely some centuries after the life of the putative founder. We have no way of knowing whether this fiction is based on a true story. Nothing much is left when we strip out the clearly ahistorical details. At present we have no way to probe beyond the event horizon of the texts. And the date when any given text was composed is uncertain by several centuries at least, even if we do have a clue when it was written down.

The position we're in is analogous to trying to understand the history of Christianity when all we had to go on were Augustine's Confessions, Dante's Inferno and Milton's Paradise Lost. They are authentic in their own way and attempt to be true to the Christian Religion, but if we had nothing earlier we'd never reproduce the history that we do have. Our guesses would most likely be wide of the mark. 
~~oOo~~