:D
But more seriously, why should my reasoning, my set theory/classical probability idea, be required for a nothing reality? It's just a tool I'm using here on hacker news to make a line of reasoning, to communicate about the possibility this sort of nothingness. I have the luxury of such a tool apparently existing, here in this universe of somethingness. But why should that have any bearing on a possible nothing universe?
I know I am being nitpicky, but despite the fact that yes, it's common to assume equal priors, this often has no basis---especially in regards to this question. With only one observation we know virtually nothing about the distribution of possible observations other than that the state that we observed is in a region with nonzero probability. We can't conclude anything else with any certainty at all.
I was happy to see that in the article the author discusses this point in particular.
That said, I definitely can relate to the gravity of existential yearnings.
An uninformed prior doesn't really make sense in this case. You have observed somethingness at least once but have never observed nothingness--only conjectured its existence. If 1) your observations are correct and 2) somethingness is mutually exclusive with nothingness then your prior distribution should approach [1, 0], not [0.5, 0.5].
Let's assume that at least "one" existence of "something" is possible, and that it corresponds with the one that you, the reader, are assuming to be experiencing right now. Somethingness.
Okay, then let's make the leap and say it's possible that nothing could be.
At this point, the odds of nothing existing are 1/2, because the set of possible universes is [nothing, something]. And if we go by the assumptions that every possible state in this set of possible states is equally likely (a common assumption in classical probability theory), but that only one state can be actualized, then this is leaving us with 1/2.
But then think about all the possible "existences" that could exist as different combinations of the substance around you. The state space is huge. Nothingness forms a vanishingly small part of that set of possible existences. The thing is that one form of "nothingness" is indistinguishable from another form of "nothingness". By extensionality, the set of possible existences only contains "nothingness" one time.
This is a naive set theory/classical probability theory approach to the question.
Of course, in a multiverse idea of reality, we don't necessarily have to pick one of the possible existences. They can be in some kind of larger superposition, even if they are somehow cut off from one another. Maybe nothingness is compatible with somethingness. We existers just don't happen to experience it. And how could we? What is there to experience and who is there to experience it?
Wow. Enough is enough! I feel like a wide-eyed college freshmen again!
Bye :)
P.S. It occurred to me that there might be distinguishable variations on non-existence. For example, what if the set of possible realities is: ["Nil", "nada", "null", "nothingness", "pitch black silence", "non-sense", "eternal vacuum", "something"]. Well then in this case, we are sure lucky to be here! There was a 7/8 chance that some form of nothing would be the ultimate reality!