There's quite substantial proof actually, in a way, that we can say a fair bit about what the Buddha taught. Not just the middle way, but also the Four Noble Truths, Noble Eightfold Path and all the details of the teachings in the Therevadhan tradition - it is possible that this is how he actually taught - there is plenty of evidence for it..
But different opinions on how much you can rely on that evidence.
It all depends on how much you can rely on the memory of the monks who passed down the Pali canon.
So - everyone agrees that the Mahayana sutras are much later, composed from 500 to 1000 years after the Buddha.
But the Pali Canon - that could have been composed shortly after the Buddha died. And it could record sutras that were memorized actually during the Buddha's lifetime.
Scholars are divided between those who think the earliest sutras in the Pali Canon preserve the teachings of the Buddha, those who think that only a few fragments of his teaching survive, and those who are agnostic about it. But those in favour of the "theory of authenticity" have a fair bit going for them I think.
The Guinness Book of Records of 1985 records the feat of a Buddhist monk who was first to memorize the entire Pali Canon in modern times:
BioMingun
He was able to memorize the entire canon - thousands of pages, millions of words. He was first in modern times to win the titles Tipitakadhara Dhammabhandagarika (Bearer of the Three Pitakas and Keeper of the Dhamma Treasure), in a stringent 33 day exam.
We also have texts far more ancient than the sutras memorized in the same way - the Indian Vedas.
In a culture with no writing, there would be a premium on memorization.
But as well as that - towards the end of Buddha's life, according to the sutras - the leader of the Jains died. Buddha's disciples noticed that the Jains were unsure of some of the details of their teacher's teachings, and resolved to make sure the same didn't happen to them. So they started a process of memorizing the Buddha's teachings. They did that while he was still alive, and able to help them and check their understanding of his teachings.
Then after he died, in the first Great Council - then the monks gathered together to go through all the teachings they had memorized and decide on a final version which they then recited in unison, for each of the sutras.
There were more Great Council's every hundred years roughly, until eventually the teachings were written down.
So - those who think the Pali Canon record the teachings of the Buddha think that this approach was successful - and that the sutras do record the Buddha's teachings - not word for word as he spoke them - but as memorized by his monks towards the end of his life and after he died.
Many eminent Buddhist scholars are of this view that the Pali Canon at least preserves the teachings of a single teacher, for the large part (there are a few texts that are obviously later from their style).
The main reason for thinking this is internal to the sutras themselves. For instance they don't mention writing - and writing was introduced to India soon after the Buddha died. They describe the political situation in India at the time, of many small kingdoms - something that was already changing as Buddha died and soon had changed considerably.
Sri Lanka and Southern India are unknown in the sutras- within a century or so during the empire of King Asoka then these places would be well known to educated Indians.
For that matter they don't mention King Asoka himself - great Buddhist emperor who lived a short while after the Buddha died. Later sutras do.
There are many details in the sutras that present a consistent picture of India as we understand it to have been at the time of the Buddha. All this adds up to a picture of texts that have probably been preserved unchanged since his time. If later authors had changed the texts - then surely they would include political and societal details from their own times in India and not been able to preserve this consistent picture of texts composed 500 years BCE?
So, I think myself that there is good evidence that not just core teachings but much of the Pali Canon dates back to a single teacher, the Buddha himself.
But nobody can know for sure. There are scholars who think the other way that most of the teachings are from after the time of the Buddha, and others who are agnostic about whether they date back to his time or not.
The main evidence in favour of the view that the Pali Canon comes from a later period is the evidence of layering in the sutras, that some are stylistically earlier, internal evidence that they were composed earlier.
Those who think the sutras are mainly the teachings of the Buddha explain this as due to - first some teachings that predate the Buddha included in the sutras - and also - that he taught for 45 years and during that time the style of his teaching may well have changed.
The main thing, as others have said here, is that the teachings themselves - they speak to our heart. Does it really matter whether or not the historical Buddha taught as described in the sutras? In case of the Mahayana sutras, e.g. the Heart Sutra (probably most famous of the Mahayana sutras) then - nobody thinks the text itself was composed at the time of the Buddha. It was quite possibly composed in China a few centuries AD. But - for Mahayana Buddhists, it carries the inspiration of the Buddha's teachings, of enlightenment. Indeed Mahayanists such as Zen Buddhists and Tibetan Buddhists think that this inspiration continues to this day, continually inspiring new zen koans and inspirational poems and texts that help the teachings of the Buddha to continue to speak directly to modern times and modern people.
In the case of the Pali Canon though, if you believe that they are largely the teachings of the Buddha, nobody can say you are wrong. And if that is indeed the case, then we know a huge amount about what the Buddha taught, with thousands of pages of his teachings. But the evidence for this can never be conclusive probably.
If you want to follow it up some more, see Origins of the Buddhist Sutras - were they the Teachings of the Buddha? by Robert Walker on Some ideas about Buddhist teachings
But different opinions on how much you can rely on that evidence.
It all depends on how much you can rely on the memory of the monks who passed down the Pali canon.
So - everyone agrees that the Mahayana sutras are much later, composed from 500 to 1000 years after the Buddha.
But the Pali Canon - that could have been composed shortly after the Buddha died. And it could record sutras that were memorized actually during the Buddha's lifetime.
Scholars are divided between those who think the earliest sutras in the Pali Canon preserve the teachings of the Buddha, those who think that only a few fragments of his teaching survive, and those who are agnostic about it. But those in favour of the "theory of authenticity" have a fair bit going for them I think.
The Guinness Book of Records of 1985 records the feat of a Buddhist monk who was first to memorize the entire Pali Canon in modern times:
BioMingun
He was able to memorize the entire canon - thousands of pages, millions of words. He was first in modern times to win the titles Tipitakadhara Dhammabhandagarika (Bearer of the Three Pitakas and Keeper of the Dhamma Treasure), in a stringent 33 day exam.
We also have texts far more ancient than the sutras memorized in the same way - the Indian Vedas.
In a culture with no writing, there would be a premium on memorization.
But as well as that - towards the end of Buddha's life, according to the sutras - the leader of the Jains died. Buddha's disciples noticed that the Jains were unsure of some of the details of their teacher's teachings, and resolved to make sure the same didn't happen to them. So they started a process of memorizing the Buddha's teachings. They did that while he was still alive, and able to help them and check their understanding of his teachings.
Then after he died, in the first Great Council - then the monks gathered together to go through all the teachings they had memorized and decide on a final version which they then recited in unison, for each of the sutras.
There were more Great Council's every hundred years roughly, until eventually the teachings were written down.
So - those who think the Pali Canon record the teachings of the Buddha think that this approach was successful - and that the sutras do record the Buddha's teachings - not word for word as he spoke them - but as memorized by his monks towards the end of his life and after he died.
Many eminent Buddhist scholars are of this view that the Pali Canon at least preserves the teachings of a single teacher, for the large part (there are a few texts that are obviously later from their style).
The main reason for thinking this is internal to the sutras themselves. For instance they don't mention writing - and writing was introduced to India soon after the Buddha died. They describe the political situation in India at the time, of many small kingdoms - something that was already changing as Buddha died and soon had changed considerably.
Sri Lanka and Southern India are unknown in the sutras- within a century or so during the empire of King Asoka then these places would be well known to educated Indians.
For that matter they don't mention King Asoka himself - great Buddhist emperor who lived a short while after the Buddha died. Later sutras do.
Asoka's empire covered much of India in 3rd century BC, but the sutras have no mention of it and don't predict it either. And describe an India of many small countries, without writing, and with Southern India and Sri Lanka unknown. To some scholars at least, this suggests that they were probably composed before the time of King Asoka.
There are many details in the sutras that present a consistent picture of India as we understand it to have been at the time of the Buddha. All this adds up to a picture of texts that have probably been preserved unchanged since his time. If later authors had changed the texts - then surely they would include political and societal details from their own times in India and not been able to preserve this consistent picture of texts composed 500 years BCE?
So, I think myself that there is good evidence that not just core teachings but much of the Pali Canon dates back to a single teacher, the Buddha himself.
But nobody can know for sure. There are scholars who think the other way that most of the teachings are from after the time of the Buddha, and others who are agnostic about whether they date back to his time or not.
The main evidence in favour of the view that the Pali Canon comes from a later period is the evidence of layering in the sutras, that some are stylistically earlier, internal evidence that they were composed earlier.
Those who think the sutras are mainly the teachings of the Buddha explain this as due to - first some teachings that predate the Buddha included in the sutras - and also - that he taught for 45 years and during that time the style of his teaching may well have changed.
The main thing, as others have said here, is that the teachings themselves - they speak to our heart. Does it really matter whether or not the historical Buddha taught as described in the sutras? In case of the Mahayana sutras, e.g. the Heart Sutra (probably most famous of the Mahayana sutras) then - nobody thinks the text itself was composed at the time of the Buddha. It was quite possibly composed in China a few centuries AD. But - for Mahayana Buddhists, it carries the inspiration of the Buddha's teachings, of enlightenment. Indeed Mahayanists such as Zen Buddhists and Tibetan Buddhists think that this inspiration continues to this day, continually inspiring new zen koans and inspirational poems and texts that help the teachings of the Buddha to continue to speak directly to modern times and modern people.
In the case of the Pali Canon though, if you believe that they are largely the teachings of the Buddha, nobody can say you are wrong. And if that is indeed the case, then we know a huge amount about what the Buddha taught, with thousands of pages of his teachings. But the evidence for this can never be conclusive probably.
If you want to follow it up some more, see Origins of the Buddhist Sutras - were they the Teachings of the Buddha? by Robert Walker on Some ideas about Buddhist teachings
About the Author
Robert Walker
Writer of articles on Mars and Space issues - Software Developer of Tune Smithy, Bounce Metronome etc.Studied at Wolfson College, Oxford
Lives in Isle of Mull
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