= 27d567bc2d48d9f40e9ccc20ea370b15)
MixedNuts comments on Mixed Reference: The Great Reductionist Project - Less Wrong
You are viewing a comment permalink. View the original post to see all comments and the full post content.
= 783df68a0f980790206b9ea87794c5b6)
Loading…= b715d02e85f7b3b4ae65ca3d3e450868)
Subscribe to RSS Feed
Powered by Reddit
= f037147d6e6c911a85753b9abdedda8d)
You are viewing a comment permalink. View the original post to see all comments and the full post content.
Comments (353)
Agreed. The number two is ridiculous and can't exist. Once you allow stuff to have a physical kind and a logical kind, what's to stop you from adding other kinds like degree-of-realness and Buddha-nature?
OTOH, logical abstractions steadfastly refuse to be reduced to physics. There may be hope for the other way around, a solution to "Why does stuff exist?" that makes the universe somehow necessary. (Egan's "conscious minds find themselves" is cute but implies either chaotic observations or something to get the minds started.) But we can't be very optimistic.
That's Tegmark's Mathematical Universe Hypothesis, the best explanation I've seen of is Section 8.1 “Something for Nothing” in Good and Real by Gary Drescher.
For math as mere physics, see Egan's Luminous.
This problem is already solved, the answer is here: http://arxiv.org/abs/0704.0646
I don't get it. Okay, obviously our universe is a mathematical structure, that's why physics works. "All math is real" is seductive, but "All computable math is real, but there are no oracles" is just weird; why would you expect that without experimental evidence of Church-Turing?
The idea that since there are twice as many infinite strings containing "1010" than "10100", the former must exist twice as much as the latter nicely explains why our universe is so simple. But I'm not at all convinced that universes like ours with stable observers are simpler than pseudorandom generators that pop out Boltzmann brains.
That all math is "real" in some sense you observe directly any time you do any. The insight is not that math is MORE real than previously thought, but just that there isn't some additional find of realness. Sort of, this is an oversimplification.
Also check out: http://lesswrong.com/lw/1zt/the_mathematical_universe_the_map_that_is_the/
That post is a confused jumble of multiple misinterpretations of the word "exist".
If all levels of the Turing hierarchy are about as real, it's extremely unlikely our universe is at level zero. Yet Church-Turing looks pretty solid.
Combine this with the simulation hypothesis; a universe can only simulate less computationally expensive universes. (Of course this is handwavy and barely an argument, but it's possible something stronger could be constructed along these lines. I do think that much more work needs to be done here.)
I'm pretty sure Eliezer's approach is the opposite of Tegmark's. For Tegmark, the math is real and our physical world emerges from it, or is an image of part of it. For Eliezer, our world, in all its thick, visceral, spatiotemporal glory, is the Real, and logical, mathematical, counterfactual, moral, mentalizing, essentializing, and otherwise abstract reasoning is a human invention that happens to be useful because its rules are precisely and consistently defined. There's much less urgency to producing a reductive account of mathematical reasoning when you've never reified 'number' in the first place.
Of course, that's not to deny that something like Tegmark's view (perhaps a simpler version, Game-of-Life-style or restricted to a very small subset of possibility-space that happens to be causally structured) could be true. But if such a view ends up being true, it will provide a reduction of everything we know to something else; it won't be likely to help at all in reducing high-level human concepts like number or qualia or possibility directly to Something Else. For ordinary reductive purposes, it's physics or bust.