Cut One
Most of what we know how to do, we know because we learned to cut things apart first. A physicist isolates a system from its surroundings to study it cleanly. A doctor treats an organ as if it could be reasoned about apart from the rest of the body, at least provisionally. The knife is not a metaphor for violence here so much as for method: separate the thing you want to understand from everything else, hold the rest still, and see what the piece does on its own. Most of the time, astonishingly, this works.
Cut Two
There is a class of experiments, refined and repeated over decades, in which two particles are prepared together and then sent apart, sometimes very far apart, before anyone measures either one. When the measurements happen, the outcomes turn out to be correlated in a way that no arrangement of hidden, independent properties carried along by each particle since their parting can fully explain. The particles behave, statistically, as though the measurement made on one is somehow tied to the measurement made on the other, even though nothing recognizable as a signal seems to have passed between them in the time available.
Cut Three
It would be easy, and wrong, to describe this as a message travelling faster than light. It is not. Neither observer can use their own result, alone, to learn anything about what is happening at the other location, and no arrangement of this correlation lets two people send usable information to each other faster than a light signal could carry it between them. The strangeness shows up only afterward, when the two separate lists of outcomes are brought together and compared, and the pattern between them turns out to be tighter than ordinary separateness would allow. The knife, in other words, didn't fail to cut. It cut, and something about the correlation refused to be fully explained away by the cut.
Cut Four
Long before any of this, a strand of Upanishadic thought was making its own case against absolute separateness, on entirely different grounds. Its claim was not about particles or measurement outcomes but about selfhood: that the boundary we draw around an individual self, so confidently, so usefully, is not the deepest fact about what that self is, and that beneath the apparent many there is a continuity the ordinary sense of separateness obscures rather than reveals. This is a metaphysical claim, arrived at through contemplation and argument, not through instruments, and it was never meant to be checked with a detector.
Cut Five
I don't think the resemblance between these two refusals of the knife earns the sentence people reach for, that entangled particles somehow prove the old teaching right, or that Brahman has finally been detected in a laboratory. The correlation between two photons is a narrow, mathematically specific fact about measurement statistics, confirmed under exacting conditions, silent on the question of selfhood entirely. The Upanishadic claim is a much larger wager about the nature of consciousness and the world, made without needing any experiment to back it. What they share is only this: both found, in their own domain, a place where an unqualified belief in separateness stopped giving the right answer, and both had the discipline to say so, on the terms their own domain could actually support.