A pair of conjoined twins can read each other's thoughts and see through each other's eyes. Are they two people, or one?
http://www.dailymail.co.uk/news/article-1331769/Doctors-stun...
A person has left and right hemispheres in their brain. Under some circumstances, losing one of these hemispheres will result in an almost normal functional human being. Imagine, with advances in biology and medicine, one day we can separate one person's brain, and place one half in one body, and the other half in another (artificial body or one whose original owner became brain dead), and both functioning as people. Are they two people, or one?
I think it depends on the observer. Some people would choose to see (one or both cases) as two people, and some would choose to see them as one.
But let us go back into history. The universe started from the big bang, as a big expanding cloud of hot gases. It was one point, and then it became one cloud. Billions of years and lots of things happening later, bits of that cloud grew eyes, legs and started to think for themselves. Are those individual bits of the universe, many individuals, or one universe?
I think, both. It's like asking a network of neurons, are you one, or many?
The universe is a conscious system. It can see itself through many eyes. It sees different parts of itself. It is having many thoughts.
I, a shard of the universe, have replied to you, another shard of the universe, by typing this on yet another shard of the same universe, at the same time as my own neurons are communicating to each other.