If you’re interested in spirituality, you might well think so. For example, I’ve been debating an acquaintance who recognizes the major disharmonies between the doctrines of the major religions, but thinks that:
…on the experiential plane, the mystics in all these religions report an almost identical experiential awareness of God… If you remove the religion specific vocabulary or substitute those with a non-sectarian meaning the experiential records of the mystics are indistinguishable.
The obvious question that occurs to me at this point is…
Do the mystics’ own testimonies bear this out?
The only way to know whether a claim is true is to assess the evidence for it. If there is no evidence, we cannot tell if it is true. If there is good evidence, we can. Or if there is evidence pointing the other way, we can know it is false.
So if we suspect that Jesus, Buddha, Muhammad et al had basically the same mystical experiences, then we need to assess what Jesus, Buddha, Muhammad et al said about their own experiences. We need to compare them and see whether they are actually identical.
Are the experiential records of these people similar?
Simply, and very obviously, no. That’s the strikingly bizarre thing about this theory. The testimonies of the mystics themselves utterly undermine the notion that they all experienced the same thing.
For example, the claims of Jesus alone completely disprove the theory. He is unique in claiming to be God. According to those closest to him,* he believed himself to be the actual word of God (dabar Yahweh) who appeared repeatedly in the Old Testament (Gen 15:1; 1 Sam 3; 1 Sam 15:10 etc), and was God himself (Jer 1:4, 6-7 etc). He did not merely think he was in union with something like what we conceive of as God, nor that he was aware of some higher reality akin to a cosmic consciousness. The culture of the time certainly had the language for him to have expressed these ideas if he had intended to, but he specifically denied this kind of interpretation by claiming to be the incarnation of Yahweh.
By contrast, the Buddha claimed to be neither (a) god nor a man, and implicitly denied the existence of a personal god who could be named by claiming that the ultimate reality was a non-personal cosmic consciousness with which we must all become one. His experience was that the self is an illusion, extinguished in nirvana. Whatever that experience entailed, it cannot have been identical to what Jesus experienced, given that Jesus claimed to be “I AM”—that is, the self-existent person. Nirvana and I AM are diametrical opposites.
Muhammad, on the other hand, believed in a personal God, but denied that Jesus (or anyone) was that God. He expressly claimed to have been given revelation by the archangel Gabriel, in the form of specific words to write down, with specific meaning. Now, that experience in itself is very similar to the experience of Old Testament prophets. But the content of the revelation is part of the experience itself—and the content experienced by the prophets contradicts that experienced by Muhammad. They had different experiences again.
It is provably false that the major religious “mystics” shared identical experiences
Whatever you may think about the ultimate truths of existence, and about which religions are closer to those truths, you simply cannot claim that the founders of those religions were all pointing to the same thing. They manifestly, by their own testimony, had completely different, contradictory mystical experiences. That might be disappointing for your own theory about religious experience and divinity, but to suggest otherwise is simply dishonest.
* We have every reason to believe Jesus’ disciples reliably recorded his words. If you doubt this, then you must doubt far more that Buddha’s disciples reliably recorded his words, which were only committed to writing 400 years after his death—as opposed to the 30–40 years for Jesus.