On 26 Dec 2010, at 22:51, Brian Tenneson wrote:

"Limits To Science: God, Godel, Gravity" http://www.science20.com/hammock_physicist/limits_science_god_godel_gravity Here is my comment: An important question is whether or not a TOE will be finite in length.

`Of course, this is a matter of definition. In mathematical logic`

`theories can be infinite, and even formula can be infinite. But I`

`prefer to limit the use of the term "theories" to finite and even`

`effective (partially decidable) theories, for pedagogical reasons,`

`which are also conceptual reason in the mechanist framework where we`

`have clear finite theories of everything (indeed all first order`

`specification of any Turing complete (Sigma_1-complete) systems`

`(machine, relative numbers, ...) is a TOE, from which we can derive`

`the correct coherent consciousness/reality couplings.`

I am taking 'TOE' to be, as a working definition, a complete description of reality or a complete description of everything that exists.

`That does not exist. Arithmetical truth is already not recursively`

`enumerable.`

Reality is infinitely vast at least for the reason that it contains all the integers, not to mention the vastness of the physical multiverse. So a TOE can be an infinite document. But like the digits of pi, perhaps this infinitely long document can be computed to arbitrary precision in a finitely long program, set of instructions.

`Here "computed" is ambiguous. A priori the UD is such a program, but`

`it makes the physical reality a non computable border of a vastly`

`bigger and non computable reality. Even the comp God cannot not lost`

`itself in the yet intelligible part of it (comp makes the NOÛS (the`

`Intelligible) bigger than God!). The comp God is overwhelmed by his`

`creation!`

Then one *might* consider this program which generates a TOE to arbitrary precision to be "the" TOE, a compression of an infinitely long document into a finitely long document, thus showing that reality at its core does not possess the trait of Kolmogorov randomness. Being that reality contains the uncomputable, it *seems* unlikely that everything can be finitely describable.

`This is simply wrong. The universal dovetailer generate all programs'`

`executions, including their 2^aleph_0 non computable environments. I`

`refer you to a very old discussion, with Schmidhuber, on this list.`

`Although, by definition, incompressible sequences can not be generated`

`by an algorithm generating only that sequence, it is easy to write a`

`program generating them all.`

`This is a terribly common error. The same with the finite sequences.`

`Most need programs as lengthy as themselves to be generated, yet the`

`counting algorithm which just counts: 0, 1, 10, 11, 100, 101, ... will`

`generate all sequences. And the counting algorithm is much small than`

`almost all finite sequences (almost all = all with a finite number of`

`exceptions). Likewise the universal dovetailer generates all the real`

`numbers, and all activities of programs confronted with those sequences.`

However, I believe that there is a TOE (complete description of reality) whose *form* can be written down. This TOE has a "shape" to it, but without specifying any more details than that. It's an existence proof of a plausible form a TOE could be in. It is roughly based on Tegmark's article entitled the Mathematical Universe Hypothesis (available on arxiv.org) which can be broken down to rely on the axiom that reality is independent of humans which is possibly controversial.

Physical reality is dependent of Löbian machines.

`If we are such machine, then physical reality is derivable (yet non`

`algorithmically) from their theology, making it testable.`

The argument is made that a TOE can be in the form of a logical structure which is a tuple consisting of an underlying set, a set of distinguished constants (like zero), functions (like successor), and relations (like less than) on this underlying set. Making the additional assumption that if there is a structure such that *all* logical structures can be "embedded" within it, then this type of universality endows such a structure with the same structure as reality. Thus this sort of ultimate structure would be in an intuitive sense like ultimate reality. Thus a description of this ultimate structure would be a description of reality.

`You have to distinguish the outside and inside view of the ultimate`

`reality.`

`With DM there is more than this distinction, which leads to the`

`"real", the provable, the knowable, the observable, the "feelable",`

`and they all split in two (except the knowable, and arguably the`

`"real") due to the personal embedding in that structure (the G/G*`

`split). This explain the difference between qualia (non sharable) and`

`quanta (sharable, first person plural).`

To do this, I employ a different-than-usual set theory called NFU which stands for new foundations with urelements as explained by Randal Holmes' textbook on NFU. The NFU has been shown to be consistent which cannot be said of the more famous ZF or ZFC set theories. The NFU also has a universal set (a set containing all sets) and a "stratified comprehension theorem" which essentially states that any object of the form {x : F} where F is any "stratified" formula is a set in NFU. An example of a *non*-stratified formula F is the infamous formula used in Russell's paradox: x is not an element of x. Thus the object considered in Russell's argument isn't a set and from this argument, no Russell-type contradictions can be derived from the universal set axiom + stratified comprehension. Within NFU, it is possible to see that the object which contains *all* structures is a set. Then one can form the "reduced product" of all structures, using this set as the index set. One feature of a reduced product is that it is a logical structure and another feature is that every structure used to form the product (in this case, every structure) is embedded within the reduced product. The reduced product of all structures is the ultimate structure as described a few paragraphs above.

`Hmm... Well, thanks to the link. I might send some feedback there`

`perhaps.`

Happy christmas and happy new year 2011 people, Bruno

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