There is a thought experiment by the philosopher Max Black that calls into question one of the basic rules of logic: the principle of indiscernable identity. The full description of the experiment is at the link.
However, the short version is this: imagine you're told about an object x, and later about an object y. You can't see either one, perhaps because they are too small or too far; but over time your sources tell you about their various properties through experiments of one kind or another.
Over time you learn that every property that x has, y has also; and vice versa. What you would tend to conclude is that "they" are the same object: x and y simply have been given two different names. If you get to the point that you have established all of their properties, and you continued to find that they each had all and only the same properties, you could logically conclude that this was the case.
Max Black posited a universe in which there were only two objects. They each had all and only the same properties; but because they were the only two objects in the universe, there were no properties that x had that y didn't have also. (E.g., "X is five feet away from the other object in the universe." How far is y? Well, five feet.)
This would lead you to conclude logically that x and y were identical, but in fact they are not the same. You couldn't come up with any property except the name that would distinguish them, and the whole purpose of this rule is to eliminate duplicate names.
I mention all this because it occurred to me that our Buddhist had a plausible answer.
Quantum theory states that any physical system remains in a superposed state of all possibilities until it interacts with the mind of an observer. Both quantum theory and Buddhist teachings on sunyata suggest that as soon as an observer's mind makes contact with a superposed system, all the numerous possibilities collapse into one actuality. At some instant one of these possible alternative universes produced an observing lifeform - an animal with a nervous system which was sufficiently evolved to form a symbiotic association with a primordial mind. The first act of observation by this mind caused the entire superposed multiverse to collapse immediately into one of its numerous alternatives.As soon as you introduce an observer, so that the two objects are not "indiscernable," the whole thought experiment collapses. If you could introduce an artillery officer, for example, you could tell him, "Hit that one, not that other one."
If the universe can't have but the two objects, but one of them is sentient, he will observe the other object as separate from himself. If the universe can only have two objects and they must have the same properties -- i.e., they must both be sentient -- the observing object can still identify the separate object: "That one is not me." Finally, if both objects' property of consciousness is fully the same, so that they are sharing a single consciousness, they really are the same creature.
Thus, the basic rules of logic hold -- in a universe with an observer.
If both quantum theory and logic require an observer to make certain statements about reality, does that mean that the two things are both flawed models that are the products of the same kind of conscious mind? Or does the similarity imply that the universe really does, as the Buddhist suggests, need a conscious mind to achieve actual (rather than potential) realities?
I don't know, but I met a professor with degrees in both physics and metaphysics today who was scratching his head after I asked him.