Necessary Thing

[robvalue]

You're still talking about observable reality, there. It may not be directly observable, such as things that were in the past or whatever, but it's things that could have been observed. You're talking about inductive reasoning regarding elements of a space/time reality we generally understand.

I'm talking about speculating further than that.

For example, say there an infinite number of other, self contained, realities. We are inside just one, and we can never get out of it. Neither can anything in any of the others.

We can't simply apply our rules of how the contents of our reality works to any other realities, nor can we apply them to how the realities themselves behave. We could assume that they do apply for the sake of speculation, but we can't possibly know if we are right or not.

Also, there may be more going on in our reality than we can ever observe. "Behind the scenes" processes or entities, behaving in bizarre ways. We can't just say there isn't, or that they must follow the rules of the things we can observe.

If you're going to exclude all these other unfalsifiable propositions, then you're reduced to scientific modelling only, and your claims will only be true within observable reality.