Nisan comments on Fine-tuned for Interestingness vs. Ramsey's Theorem - Less Wrong

0 Post author: Alexandros 16 May 2011 05:07PM

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Comment author: Nisan 16 May 2011 06:57:20PM 3 points [-]

No, there are analogous theorems about structures other than graphs. But there are not analogous theorems about all structures.

In order to use Ramsey theory to dispute the physicists' claim that "most universes are lifeless" (which is backed up by a technical, though not indefeasible argument), one would have to make a technical argument that

  • identifies counterfactual universes with members of a class C of mathematical objects;
  • identifies life or interestingness with certain features of the members of C;
  • identifies a Ramsey-type theorem for C that has been proven.

I don't imagine this can be done in an interesting way.

Comment author: Alexandros 18 May 2011 01:29:54PM *  0 points [-]

On your second point - my definition of interestingness is any distinguishing feature. Anything at all that can be used to tell universes apart. If you think I am talking about life or something like it, you have not understood my argument. It claims that life is an arbitrary feature to focus on to begin with. I don't know which scientists have made the 'lifeless universes' argument and how, but my argument has nothing to do with that.

On your first point - If we accept Tegmark's identification of universes-in-general with mathematical objects, the question becomes whether Ramsey Theory applies or not.

On your third point - Given that theorems exist for coloured graphs, multidimensional grids, and coloured consecutive numbers, (hardly high-level structures), it's not exceedingly far fetched to imagine ramsey-type structure arising in a universe, or our universe being expressible as one of those structures.

Yes, this last bit is speculative, and this is why I asked for feedback.

Comment author: Nisan 18 May 2011 05:29:49PM 1 point [-]

my definition of interestingness is any distinguishing feature. Anything at all that can be used to tell universes apart.

Oh, your definition of interestingness is kinda sorta the opposite of what I thought it was. "Having a monochromatic complete subgraph of a certain size" is not a distinguishing feature of sufficiently large colored complete graphs, because all such graphs have that property.

Comment author: benelliott 18 May 2011 06:35:59PM 0 points [-]

It all depends on whether you find very small areas of uniform patterns interesting.