I do not find the article on 3D space terribly convincing either—and I am the author of it—so I would have to be understanding if you don’t. It is generally my policy, though, that my articles reflect how I think of things at the time I wrote them and I don’t remove them if my views change—though I might occasionally add notes after. I do think that an anthropic explanation still works for this: I just don’t think mine was a particularly good one.
It’s a difficult topic. Life (e.g. self-replicating CA) exist fine in 2, 3 and 4 dimensions, though there is still the issue of evolving intelligence. Some say that three dimensions is the only number that permits you to tie knots, though the significance of knots is unclear. I am not convinced that 3 is terribly special—and I’m not sure we know enough about physics and biology to coherently address the issue yet.
With physical laws of character similar to ours (not a CA), though, there are further reasons to think life requires 3 space dimensions (and 1 of time).
I don’t really see how you can build an anthropic argument out of that, though. The idea that if you make a radical mutation in one aspect of a life-supporting universe, then it no longer supports life is probably not particularly unusual. For example, if you make the game of life 3D using the same totalistic rule then it no longer supports life either. That is just a consequence of dead universes being more common than living ones, and doesn’t have anything to do with there being something special about the dimensionality of our space-time.
And cellular automata don’t select for intelligence, so it is at least reasonable to conjecture that most observers evolve under physical laws of character similar to ours (and therefore, by the orbit stability argument, in three dimensions of space).
That is a topic I am more interested in. The discussion has some mertis, though it seems rather long and repetitive. At least he understands that there is an issue here. He seems to think it proved that a LLL is the best thing for Occam’s razor. I am less sure about that.
I looked at that one and had to skip to the end. What he’s getting at
doesn’t match what I, or most programmers I know, mean by “low level.”
Low level just means it’s far from how humans think. It’s low because
we like to put things on top of it that are easier for us to deal with.
The idea that it’s “close to the machine” just comes from the fact that
that’s the most popular reason to deliberately make something low level.
(Making it easy to analyze is probably the second most popular.)
But I wasn’t trying to argue that “low level” does mean “close to the machine”. That, however is a way it is often expressed. I merely listed that as one idea of “low level”. If I had not mentioned that in the article someone would have simply said “A low level language is close to the machine” and thought that dealt with it, so I had to deal with it out of completeness. I was not saying that “low level” as “close to the machine” was a formal, official idea—and I actually argued that it isn’t. I was after a language which is, as far as possible, free from prejudice towards particular applications and I was arguing that it can be non-trivial to get one. You might dispute my use of the word “low level” for this, but I would say that this is largely a semantic issue and that there is still a need for knowing that we can get a language with these properties. What I was proposing was a way of taking two languages, and testing them against each other without any reference to any third language, any hardware or any physics to determine which of them is most free of any prejudice towards particular uses—in a way, which of them is as close as possible to being free of any information content.
But I wasn’t trying to argue that “low level” does mean “close to the
machine”.
I didn’t think, and didn’t mean to imply that I thought, you were. I
mentioned it for the same reason you did: to help describe my meaning of
“low level” by its connection to something related.
I was after a language which is, as far as possible, free from
prejudice towards particular applications and I was arguing that it can
be non-trivial to get one. You might dispute my use of the word “low
level” for this, but I would say that this is largely a semantic issue
and that there is still a need for knowing that we can get a language
with these properties.
I don’t think that’s what you’re really after. When you describe what
you want, it sounds like a language that is prejudiced against
describing things that are complicated in reality, so the complexity of
the description matches the complexity of the reality.
It’s not just a semantic problem that you’re calling it “low level.”
“Low level” means it’s far from how humans think, which tends to remove
human prejudice. You call it “low level” because you think you can find
it by removing prejudice. You actually need to switch from one
prejudice to another to get what you want.
(Also, thanks for the reply. Sorry I didn’t read the whole thing, but I
got to the list of methods you had rejected, and it was just too much.
It feels a lot longer to someone who thinks the basic idea behind all
the methods is off base.)
I read the anthropic explanation why space is 3D—one of the more-promising-sounding titles. I did not find it terribly convincing.
I do not find the article on 3D space terribly convincing either—and I am the author of it—so I would have to be understanding if you don’t. It is generally my policy, though, that my articles reflect how I think of things at the time I wrote them and I don’t remove them if my views change—though I might occasionally add notes after. I do think that an anthropic explanation still works for this: I just don’t think mine was a particularly good one.
It’s a difficult topic. Life (e.g. self-replicating CA) exist fine in 2, 3 and 4 dimensions, though there is still the issue of evolving intelligence. Some say that three dimensions is the only number that permits you to tie knots, though the significance of knots is unclear. I am not convinced that 3 is terribly special—and I’m not sure we know enough about physics and biology to coherently address the issue yet.
With physical laws of character similar to ours (not a CA), though, there are further reasons to think life requires 3 space dimensions (and 1 of time).
Max Tegmark: On the dimensionality of spacetime [PDF]
I don’t really see how you can build an anthropic argument out of that, though. The idea that if you make a radical mutation in one aspect of a life-supporting universe, then it no longer supports life is probably not particularly unusual. For example, if you make the game of life 3D using the same totalistic rule then it no longer supports life either. That is just a consequence of dead universes being more common than living ones, and doesn’t have anything to do with there being something special about the dimensionality of our space-time.
And cellular automata don’t select for intelligence, so it is at least reasonable to conjecture that most observers evolve under physical laws of character similar to ours (and therefore, by the orbit stability argument, in three dimensions of space).
I think Max Tegmark made an argument for that—and I find it more convincing.
I looked at “What is a Low Level Language” too.
That is a topic I am more interested in. The discussion has some mertis, though it seems rather long and repetitive. At least he understands that there is an issue here. He seems to think it proved that a LLL is the best thing for Occam’s razor. I am less sure about that.
I looked at that one and had to skip to the end. What he’s getting at doesn’t match what I, or most programmers I know, mean by “low level.”
Low level just means it’s far from how humans think. It’s low because we like to put things on top of it that are easier for us to deal with. The idea that it’s “close to the machine” just comes from the fact that that’s the most popular reason to deliberately make something low level. (Making it easy to analyze is probably the second most popular.)
But I wasn’t trying to argue that “low level” does mean “close to the machine”. That, however is a way it is often expressed. I merely listed that as one idea of “low level”. If I had not mentioned that in the article someone would have simply said “A low level language is close to the machine” and thought that dealt with it, so I had to deal with it out of completeness. I was not saying that “low level” as “close to the machine” was a formal, official idea—and I actually argued that it isn’t. I was after a language which is, as far as possible, free from prejudice towards particular applications and I was arguing that it can be non-trivial to get one. You might dispute my use of the word “low level” for this, but I would say that this is largely a semantic issue and that there is still a need for knowing that we can get a language with these properties. What I was proposing was a way of taking two languages, and testing them against each other without any reference to any third language, any hardware or any physics to determine which of them is most free of any prejudice towards particular uses—in a way, which of them is as close as possible to being free of any information content.
I didn’t think, and didn’t mean to imply that I thought, you were. I mentioned it for the same reason you did: to help describe my meaning of “low level” by its connection to something related.
I don’t think that’s what you’re really after. When you describe what you want, it sounds like a language that is prejudiced against describing things that are complicated in reality, so the complexity of the description matches the complexity of the reality.
It’s not just a semantic problem that you’re calling it “low level.” “Low level” means it’s far from how humans think, which tends to remove human prejudice. You call it “low level” because you think you can find it by removing prejudice. You actually need to switch from one prejudice to another to get what you want.
(Also, thanks for the reply. Sorry I didn’t read the whole thing, but I got to the list of methods you had rejected, and it was just too much. It feels a lot longer to someone who thinks the basic idea behind all the methods is off base.)