## LESSWRONGLW

Your note about Gödel's theorem is confusing or doesn't make sense. There is no such thing as an inconsistent math structure, assuming that by "structure" you mean the things used in defining the semantics of first order logic (which is what Tegmark means when he says "structure", unless I'm mistaken).

The incompleteness theorems only give limitations on recursively enumerable sets of axioms.

Other than that, this looks like a great resource for people wanting to investigate the topic for themselves.

I would also add just to remember the idea, that logical paradoxes inside logical universe may look like logical black holes, and properties of these black holes may have surprising similarities with actual black holes.

Logical black holes may attract lines of reasonings, but nothing could come out of them, and in the middle they have something where main laws contradict each other the same way as physical laws are undefined in the gravitational singularity of astronomical black hole.

Epistemic status: crazy idea.

0turchin3yThanks, I am not very kin with Godel theorem, but some paradoxes in math exists, like the one about set of all sets - does it contains itself? If we claim that math is final reality, we must find the way to deal with them.

# 5

There is a question which is especially disturbing during sleepless August nights, and which could cut your train of thought with existential worry at any unpredictable moment.

The question is, “Why does anything exist at all?” It seems more logical that nothing will ever exist.

A more specific form of the question is “How has our universe appeared from nothing?” The last question has some hidden assumptions (about time, universe, nothing and causality), but it is also is more concrete.

Let’s try to put these thoughts into some form of “logical equation”:

1.”Nothingness + deterministic causality = non existence”

2. But “I = exist”.

So something is wrong in this set of conjectures. If the first conjecture is false, then either nothingness is able to create existence, or causality is able to create it, or existence is not existence.

There is also a chance that our binary logic is wrong.

Listing these possibilities we can create a map of solutions of the “nothingness problem”.

There are two (main) ways in which we could try to answer this question: we could go UP from a logical-philosophical level, or we could go DOWN using our best physical theories to the moment of the universe’s appearance and the nature of causality.

Our theories of general relativity, QM and inflation are good for describing the (almost) beginning of the universe. As Krauss showed, the only thing we need is a random generator of simple physical laws in the beginning. But the origin of this thing is still not clear.

There is a gap between these two levels of the explanation, and a really good theory should be able to fill it, that is to show the way between first existing thing and smallest working set of physical laws (and Woldram’s idea about cellular automata is one of such possible bridges).

But we don’t need the bridge yet. We need explanation how anything exists at all.

How we going to solve the problem? Where we can get information?

Possible sources of evidence:

1. Correlation between physical and philosophical theories. There is an interesting way to do so using the fact that the nature of nothingness, causality and existence are somehow presented within the character of physical laws. That is, we could use the type of physical laws we observe as evidence of the nature of causality.

While neither physical nor philosophical ways of studying the origin of the universe are sufficient, together they could provide enough information. This evidence comes from QM, where it supports the idea of fluctuations, which is basically ability of nature to create something out of nothing. GR theory also presents idea of cosmological singularity.

The evidence also comes from the mathematical simplicity of physical laws.

2. Building the bridge. If we show all steps from nothingness to the basic set of physical laws for at least one plausible way, it will be strong evidence of the correctness of our understanding.

3. Zero logical contradictions. The best answer is the one that is most logical.

4. Using the Copernican mediocrity principle, I am in a typical universe and situation. So what could I conclude about the distribution of various universes? And from this distribution what should I learn about the way it manifested? For example, a mathematical multiverse favors more complex universes; it contradicts the simplicity of observed physical laws and also of my experiences.

5. Introspection. Cogito ergo sum is the simplest introspection and act of self-awareness. But Husserlian phenomenology may also be used.

Most probable explanations

Most current scientists (who dare to think about it) belong to one of two schools of thoughts:

1. The universe appeared from nothingness, which is not emptiness, but somehow able to create. The main figure here is Krauss. The problem here is that nothingness is presented as some kind of magic substance.

2. The mathematical universe hypothesis (MUH). The main author here is Tegmark. The theory seems logical and economical from the perspective of Occam’s razor, but is not supported by evidence and also implies the existence of some strange things. The main problem is that our universe seems to have developed from one simple point based on our best physical theories. But in the mathematical universe more complex things are equally as probable as simple things, so a typical observer could be extremely complex in an extremely complex world. There are also some problems with the Godel theorem. It also ignores observation and qualia.

So the most promising way to create a final theory is to get rid of all mystical answers and words, like “existence” and “nothingness”, and update MUH in such a way that it will naturally favor simple laws and simple observers (with subjective experiences based on qualia).

One such patch was suggested by Tegmark in respond to criticism of MUH, a computational universe (CUH), which restricts math objects to computable functions only. It is similar to S.Wolfram’s cellular automata theory.

Another approach is the “logical universe”, where logic works instead of causality. It is almost the same as mathematical universe, with one difference: In the math world everything exists simultaneously, like all possible numbers, but in the logical world each number N is a consequence of  N-1. As a result, a complex thing exists only if a (finite?) path to it exists through simpler things.

And this is exactly what we see in the observable universe. It also means that extremely complex AIs exist, but in the future (or in a multi-level simulation). It also solves the meritocracy problem – I am a typical observer from the class of observer who is still thinking about the origins of the universe. It also prevents mathematical Boltzmann brains, as any of them must have possible pre-history.

Logic still exists in nothingness (or elephants could appear from nothingness). So a logical universe also incorporates theories in which the universe appeared from nothing.

(We could also update the math world by adding qualia in it as axioms, which would be a “class of different but simple objects”. But I will not go deeper here, as the idea needs more thinking and many pages)

So a logical universe seems to me now a good candidate theory for further patching and integration.

Usefulness of the question

The answer will be useful, as it will help us to find the real nature of reality, including the role of consciousness in it and the fundamental theory of everything, helping us to survive the end of the universe, solve the identity problem, and solve “quantum immortality”.

It will help to prevent the halting of future AI if it has to answer the question of whether it really exists or not. Or we will create a philosophical landmine to stop it like the following one:

“If you really exist print 1, but if you are only possible AI, print 0”.

The structure of the map

The map has 10 main blocks which correspond to the main ways of reasoning about how the universe appeared. Each has several subtypes.

The map has three colors, which show the plausibility of each theory. Red stands for implausible or disproved theories, green is most consistent and promising explanations, and yellow is everything between. This classification is subjective and presents my current view.

I tried to disprove any suggested idea to add falsifiability in the third column of the map. I hope it result in truly Bayesian approach there we have field of evidence, field of all possible hypothesis and

This map is paired with “How to survive the end of the Universe” map.

Meta:

Time used: 27 years of background thinking, 15 days of reading, editing and drawing.

`Parfit – discuss different possibilities, no concrete answerhttp://www.lrb.co.uk/v20/n02/derek-parfit/why-anything-why-this`
`Good text from a famous bloggerhttp://waitbutwhy.com/table/why-is-there-something-instead-of-nothing`
`“Because "nothing" is inherently unstable”http://www.bbc.com/earth/story/20141106-why-does-anything-exist-at-all`
`Here are some interesting answers https://www.quora.com/Why-does-the-universe-exist-Why-is-there-something-rather-than-nothing`
`Krauss “A universe from nothing”https://www.amazon.com/Universe-Nothing-There-Something-Rather/dp/1451624468`
`Tegmark’s main article, 2007, all MUH and CUH ideas discussed, extensive literature, critics respondedhttp://arxiv.org/pdf/0704.0646.pdf`
`Juergen Schmidhuber. Algorithmic Theories of Everythingdiscusses the measure between various theories of everything; the article is complex, but interestinghttp://arxiv.org/abs/quant-ph/0011122`
`ToE must explain how the universe appeared`
`https://en.wikipedia.org/wiki/Theory_of_everything `
`A discussion about the logical contradictions of any final theoryhttps://en.wikipedia.org/wiki/Theory_of_everything_(philosophy“The Price of an Ultimate Theory” Nicholas Rescher Philosophia Naturalis 37 (1):1-20 (2000)`
`Explanation about the mass of the universe and negative gravitational energyhttps://en.wikipedia.org/wiki/Zero-energy_universe`