Specifically, he says that Buddhism teaches us that we ARE our neighbor,
I see the heavy hitters have come in to correct a few things - so i’ll just make a few footnotes to what Contarini and Rossum have stated.
GK Chesterton seems a bit muddled about his understanding of “same consciousness,” because while something akin to what is meant is upheld in 1 version of Buddhism and a few versions of Hinduism, it isn’t exactly like saying “Bob and Mike have the same thoughts.”
Let’s chop this up - first the Hindu perspective, than a contrasting Buddhist one.
1.) Jiva = “Life principle” with a dash of a “Personal self” ~ sometimes translated into English as “Soul.” The Jiva is an Immaterial, Immortal, Indestructible entity that is embodied and eventually dies only to find itself in another body again. It is highly fallible, prone to confusion, and most likely to act on a combination of one’s desires and fears resulting in the accumulation of negative Karma which results in “Re-death” (a better translation than saying “reincarnation” or “re-birth” because it emphasizes the fear felt by those who believe in such things about being caught forever in Cyclic Existence => Samsara).
The cause of all of these issues =
Ignorance. But of what?
2.) Atman = The Universal Soul. Often dubbed the “True Self,” it is often correlated to Brahma
n which is the underlying transcendental reality of all things. This One Soul/True Soul/whatever acts as the “Ground of All Being” for the multiple Jivas that exist so that Atman exists in All Things.
The whole goal of one rather strongly philosophical strand of Hinduism is to take your little Jiva and purify it enough to the point that it becomes identified with Atman.
So since Atman = Brahman, and if Purified Jiva = Atman, then your Jiva becomes one with Everything. This is the Non-Dualist position upheld in some forms of Hinduism which emphasizes the utter destruction of distinction between yourself, God, and the Universe…
…and then Buddhism comes in and takes a wrecking ball to the whole notion of Jivas and Atman. Early Buddhisms psychological system and cosmology seems to be geared toward undermining the concept of Jiva-Atman that was so prevelant in Indian society at the time.
But there was a specific philosophical school in later Mahayana Buddhism that does possess entities that look quite similar…if you believe the critics of the school that is.
In Yogachara Buddhism, there exists a thing called the
ālaya-vijñāna, the “storehouse consciousness” that retains the experiential impressions that you/me/everyone else/perhaps ever conscious thing that has/does/will exist. It is this consciousness that eventually induces “rebirth” in a person.
The Anti-Yogachara Philosophical schools tend to look at this
ālaya-vijñāna as nothing more than Atman snuck through the back door and the
Tathagatagarba, the potential for Buddha-Nature in all beings, to be Jiva or the Soul also snuck through the back door.
It all gets highly polemical, akin to watching Catholics and Orthodox scream about Thomas Aquinas vs. Gregory Palamas or watching Muslims debate whether the Qur’an is Uncreated and Existed with God/Allah before Time began or if it was created in a Moment of Time by God/Allah.
Suffice it to say though, the above the notions are as close as anyone can get to Chersterton’s assertion that people will have the “same consciousness”…