If one asserts that the validity of the teachings rests purely upon historical accuracy, meaning that they must be the exact words of the Buddha, then this is truly a matter of blind faith, because we cannot prove what the Buddha actually said. We believe that the Pali teachings are his exact words, but that is still a matter of personal belief. Some texts may have been added later, or they may be distortions of what the Buddha said.
Conceivably, they might even be the words of someone who lived at the same time, who was posing as the Buddha. India is a big place and there is no shortage of "enlightened masters". Of course, this is simply random speculation, but it is not outside the realm of possibility, and when you are talking about historical proof of something that occurred over 2500 years ago, you have to consider a lot of possibilities. This is especially true if the people who wrote the teachings down for the first time, unless they were 100 years old, had never actually met the Buddha, and that they were written down in Sri Lanka, some 5,000 miles south of where the Buddha is supposed to have given most of his teachings. So, I don't think it is unreasonable to allow for a rather large margin of error.
To me it is ironic that so many who follow only the Theravada are quick to dismiss the Mahayana and Vajrayana teachings as having turned 'pure dharma' into a 'religion', merely because the rituals and practices and commentaries through which the teachings have been preserved resemble those of the Hindu and Judeo-Christian Traditions.
But, is it the outward manifestations of a tradition, its trappings, holidays, its bells and whistles, that make something a religion, or is it a question faith vs. application? While it is true that Mahayana and Vajrayana traditions assert much which cannot be immediately tested in this lifetime, such as other Buddha-realms, bardo states and so forth, neither do these traditions require their followers to believe (on blind faith) what they cannot perceive directly . Instead, one must put what one learns into practice constantly, testing it out under all circumstances to prove its validity.
By contrast, adhering to a teaching because one believes it to be "the real thing" can in turn lead one to deny the fact of their own personal experience, when that personal experience contradicts the teachings they follow. One person I have encountered (who adamantly denounces Mahayana, Vajrayana and even some Theravada) asserts absolutely that there is nothing that can truly be called a "self" (atma) and therefore denies that this is exactly the experience he is having. When confronted by this, he can only quote scripture, essentially saying that if Buddha said there is no 'self' then he must not be having any experience which feels like a "self". Of course, all traditions assert there is no real "self", but he even denies the fact of having that delusion (and it is precisely this delusion of a self, that we all share, that the Buddha addresses).
If the teachings do not free one from suffering, it doesn't matter who said them or what tradition they come from. Ultimately, it is up to the person practicing dharma to make it work.
Profile Picture: "The Foaming Monk"
The Chinese characters are Fo (buddha) and Ming (bright). The image is of a student of Buddhism, who, imagining himself to be a monk, and not understanding the true meaning of the words takes the sound of the words literally. Likewise, People on web forums sometime seem to be foaming at the mouth. Original painting by P.Volker /used by permission.