### Quantum entanglement between two distant particles I think Bell's inequality and its experimental confirmation is probably the most profound hint we've gotten so far about reality. In it, a pair of particles with some entangled property can be located at the two ends of the universe and _still_ be correlated. Of course, as we saw in [[Demystifying quantum theory]], this correlation wouldn't be surprising if it was simply epistemic. That is, correlation among distant particles would not be surprising if we were missing some knowledge of a "hidden" variable that determined how the properties of two particles is correlated. To see this, simply imagine that there is a pair of socks and one sock is put into one box and another sock in a different box. Now, no matter how far you take away the boxes, the results of what you see when you open your box will also be correlated with the result in the second box. If you get the right leg sock, your friend at the other side of the universe gets the left leg sock. So far, nothing surprising here. But Bell's inequality suggests that the quantum correlation is not epistemic. It's not that we _don't know_ what is determining the outcomes, rather the correlation is ontological. The outcomes for a measurement of a particle among the pair do not exist until we measure them. And yet somehow the properties of particles that are entangled are connected to each other _across space_. **It's as if the particles are connected via a channel that allows for instantaneous communication across space.** But, of course, we know nothing can go faster than the speed of light _in_ space. So, how to explain the quantum correlations that don't seem to care about the amount of space between the entangled properties? #### Perhaps space is just one among the many relationships different things can have in our universe This perspective was reinforced by [the interview where Lee Smolin](https://www.quantamagazine.org/were-stuck-inside-the-universe-lee-smolin-has-an-idea-for-how-to-study-it-anyway-20190627/) talks about he reformulated physics in terms of similarity relation between events. Two events can have similarity in space (in which case they appear close to us) but they can have similarity in other physical properties (such as spin, charge, etc.) which means **two spatially distant things can be closer to each other in some other respect.** Intuitively, I like the idea that space and time might be certain "views" of relations between some entities. Both these entities and relations between them may have some properties. This immediately reminds me of the [Wolfram Physics](https://writings.stephenwolfram.com/2020/04/finally-we-may-have-a-path-to-the-fundamental-theory-of-physics-and-its-beautiful/) project where he and his group are trying to model reality via what they call as hypergraphs.