How are you conceiving of this output stream of actions? If you think of it as just a set of experiences (e.g. the experience of throwing a rock), then I don't see how it's distinct from the input stream. If you think of it as actual actions, like actually throwing a rock, then it seems to me you've already committed yourself at this stage to an external reality -- how can you a throw a rock if there are no rocks or, for that matter, if you have no limbs? -- and "reality" isn't just an explanatory model linking your input and output streams.

You're using an AIXI-like notion of senses and actions related by a turing machine or other computation? Isn't such a model annoyingly incomplete in that it can by design provide no explanation for how the input and output streams themselves came about?

One of those models is "there is this thingy from which experiences come from, let's call it reality"

Or, to give it is full title, "there is this thingy from which experiences come from, let's call it reality, and it is in the territory and not part of the map"

it predicts our future sensory experiences so well. So much so, it is easy to forget that this is but a model.

Who's forgetting what? Our meta-model of model-making is that you can make as many models as you like of something, and the original doens't vanish. Making a model of the territory doens't turn it into a map.

If you forget it, then you start asking questions like "are all possible worlds real?" and other modal realism silliness. I

Well, you've thrown out the single world as well. All the babies went out with the bathwater.

This dissolves (for me)[..]other dangling notions like "objective truth".

I'll say. Once you have asumed that the territory is just another map, it becomes impossible to explain why anyone would care about getting into alignment with it.

t reality is a good model, it explains repeatable experiences

"I have a model which says my exeriences will repeat, therefore they will repeat". Hmmmm.

I'm having some trouble understanding you, because I'm not sure what you mean when you use the word 'model'. Could you explain that more directly? Assume my only grasp on the word has to do with small plastic airplanes.

Throwing the rock doesn't prove that the rock exists. By the time that you concretize to the point that you can talk about interacting with the world, you have already made some completely unjustifiable assumptions about how the world works. What premise allows you to make the jump from "I perceive that there is a rock there" to "There is a rock there"?

The hypothesis that reality is impermanent is nonfalsifiable; there is no way to show evidence for or against the theory that the universe came into existence already a consistent whole, including my memories of beginning to type this post. There is also no way to differentiate a universe which came into existence a moment ago and will pass out of existence in a moment from the persistent model that you use.