### Yverse: A New Model of the Universe

A new model of the universe?

Actually, yeah.

It starts out with the familiar concept of the "multiverse," which is mainly associated with the many-universes interpretation of quantum theory.

According to one verbalization of the multiversal interpretation of quantum theory, every time a quantum-random "choice" is made (say, an electron spins up instead of down), there is a "branching" into two possible universes: one where the electron spins up, another where it spins down.

Similarly, if a bus drives at you while you're walking across the street, there may be two possible universes ahead of you: one where you get flattened, and another where you don't. (Actually, there are a lot of other choices going on in your life too, so it's more accurate to say there is one set of universes where you get flattened and another where you don't).

The collection of all these possible universes is known as the "multiverse."

In fact the language of "choice" used in the above description of the multiverse is a bit suspect. It's more accurate to say that corresponding to each possible state of the electron (up/down) once it is coupled with the external environment (so that it decoheres), there is a set of branches of the multiverse, and leave the ambiguous and misleading language of "choice" out of it.

Anyway, the multiverse is fascinating enough, but it's just the beginning.

It's easy enough to think of multiple possible multiverses. After all, there could be a multiverse in which Ben Goertzel never existed at all, in any of its branches.

One way to think about backwards time travel, for instance, is as a mechanism for selecting between multiverses. If you go back in time and change something, then you're effectively departing your original multiverse and entering a new one.

So, we can think about a multi-multiverse, i.e. a collection of multiverses, with a certain probability distribution over them.

I don't posit this hypothesis all that seriously, but I'm going to throw it out there anyway: It seems possible to conceive of consciousness as a faculty that facilitates movement between multiverses!

Well, I guess you can see where all this is going.

If there's a multi-multiverse, there can also be a multi-multi-multiverse. And so on.

But that is not all -- oh no, that is not all ;-)

What about the multi-multi-...-multi-multiverse?

I.e. the entity Yverse so that

Yverse = multi-Yverse

??

Math wonks will have already inferred that I chose the name Yverse because of the Y-combinator in combinatory logic, which is defined via

Yf = f(Yf)

In other words

Yf = ...ffff...

(where the ... goes on infinitely many times)

So the Yverse is the (Y multi-) universe ...

In the Yverse, there are multiple branches, each one of which is itself a Yverse....

Two Yverses may have two kinds of relationship: sibling (two branches of the same parent Yverse) or parent-child.

Backwards time travel may jolt you from one Yverse to a parent Yverse. Ordinary quantum decoherence events merely correspond to differences between sibling Yverses.

If there is a probability distribution across a set of sibling Yverses, it may be conceived as an infinite-order probability distribution. (A first-order probability distribution is a distribution across some ordinary things like numbers or particles, or universes. A second-order probability distribution is a distribution across a set of first-order probability distributions. Well, you get the picture.... An infinite-order probability distribution is a probability distribution over a set of infinite-order probability distributions. I've worked out some of the math of this kind of probability distribution, and it seems to make sense.)

What use is the Yverse model? I'm not really sure.

It seems to be an interesting way to think about things, though.

If I had more time for pure intellectual entertainment, I'd put some effort into developing a variant of quantum theory based on Yverses and infinite-order probabilities. It seems a notion worth exploring, especially given work by Saul Youssef and others showing that the laws of quantum theory emerge fairly naturally from the laws of probability theory, with a few extra assumptions (for instance, in Youssef's work, the assumption that probabilities are complex rather than real numbers).

And reading Damien Broderick's excellent book on psi, "Outside the Gates of Science," got me thinking a bit about what kinds of models of the universe might be useful for explaining psi phenomena.

Yes, quantum theory is in principle generally compatible with psi, so one doesn't need wacky ideas like Yverses to cope with psi, but it's fun to speculate. It seems to me that for quantum theory to account for psi phenomena would require some really far-out long-range quantum-coherence to exist in the universe, which doesn't seem to be there. So in my view it's at least sensible to speculate about how post-quantum physics might account for psi more sensibly.

This babbling about psi leads back to my wacko speculation above that consciousness could be associated with action in the multi-multiverse. In the Yverse model, the idea becomes that consciousness could be associated with action in the parent Yverse.

Could the difference between physical action and mental action be that the former has to do with movement between sibling Yverses, whereas the latter has to do with movement between parent and child Yverses?

Well I'll leave you on that note --

I've gone pretty far "out there", I guess about as far as it's possible to go ;-> ....

(Unless I could work Elvis into the picture somehow. I thought about it, but didn't come up with anything....)

-- (semi-relevant, rambling) P.S. Those who are interested in my AI work may be interested to know that I don't consider any of these funky speculations contradictory to the idea of creating AI on digital computers. The whole connection between probability, complex probability, quantum theory, determinism and complexity fascinates me -- and I consider it extremely poorly understood. For example, I find the whole notion of "determinism" in very complex systems suspect ... in what sense is a digital computer program determinate relative to me, if I lack the computational capability to understand its state or predict what it will do? If I lack the computational capability to understand some thing X, then relative to my own world-view, should X be modeled according to complex rather than real probabilities, in the vein of Yousseffian quantum probability theory? I suspect so. But I won't pursue this any more here -- I'll leave it for a later blog post. Suffice to say, for now, that I have a feeling that our vocabulary for describing complex systems, with words like "determinate" and "random", is woefully inaccurate and doesn't express the really relevant distinctions.