"Entities must not be replicated beyond necessity". Both interpretations violate this rule. The only question is which violates it more. And the answer to that seems to one purely of opinion.

So throwing out the extra stuff -- they're using exactly the same math.

Not all formalizations that give the same observed predictions have the same Kolmogorov complexity, and this is true even for much less rigorous notions of complexity.

Sure. But MWI and CI use the same formulae. They take the same inputs and produce the same outputs.

Everything else is just that -- interpretation.

One simple thing it could do is simply use trial division. But another could use some more complicated process, like say brute force searching for a generator of (Z/pZ)*.

And those would be different calculations.

In this case, the math being used is pretty similar,

No, it's the same math.

and dramatically simpler than the Copenhagen interpretation

No, it is exactly as complicated. As demonstrated by its utilization of exactly the same mathematics.

. It rules out a lot of the abnormal conclusions that people draw from Copenhagen, e.g. ascribing mystical powers to consciousness, senses, or instruments.

It is not without its own extra entities of equally enormously additive nature however; and even and those abnormal conclusions are as valid from the CI as is quantum immortality from MWI.

-- I speak as someone who rejects both.

There is nothing circular about the definition -- merely recursive. "GNU" stands for "GNU is Not UNIX".

As soon as you observe two things to directly interact with one another, you may safely asssert that both exist under my definition.

This is, frankly, not very complicated to figure out.

For example, would you say that software "exists"?

No. But it is real. Software is a pattern by which electrons, magnetic fields, or photochemically-active media are constrained. The software itself is never a thing you can touch, hold, see, or smell, or taste; it never at any point is ever capable of directly interacting with anything. Just like you and me; we are not our bodies; nor our brains; nor the electrons or chemicals that flow through the brains. We are patterns those things are constrained by. I am the unique pattern that, in times past, created the password to the LW account, Logos01; and you the pattern that (I presume) created Eugine_Nier. But neither of us, physically, exist. This is important to notions of substrate-independence; where goes your pattern, is you. (Remember your Ship of Theseus problem.)

Right now I am downloading onto a VM on my workstation the 12.04 release of Lubuntu. This software is being pulled over ethernet to be delivered to a virtual harddrive image where it will be configured and installed. If I say I have LibreOffice installed too, it is clear I am talking about a specific release/instance/copy. We talk about identity in terms of software "Have you tried the latest Halo? It's awesome! ^_^" -- and two people can apparently own exactly the same game. But of course these are multiple copies of the pattern. It's even possible to talk about backups and restores. This is because the only thing that matters about defining whether something is or is not the software is that pattern.

Nations?

Real but do not exist. If every last person of the US packed their bags and got onto a rocket and shot themselves to Mars, it'd still be the United States of America. Even if every last person died while on that rocket and their kids were the ones who took over for them. Substrate independence once again demonstrates this.

Boeing 747s?

Exist. It is possible to see/hear/touch/smell/taste a Boeing 747 (I hear they taste like burnt chocolate and chicken.) It is possible for two Boeing 747's to be run into one another; or for a comet to strike one. It is not possible for a factory to churn out political constructs or minds. (Though it is possible for them to assemble all the pieces that would, when activated, allow for the presence of a mind.)

While you CAN take all the individual components of a Boeing 747 apart and put them back together again to make the same object; or over time transfer pieces into / from it (Theseus's Grandfather's Axe) -- what you can't do is just "declare" a different physical object to BE that original Boeing 747. You can't have five of the same Boeing 747. That is because it is a thing which directly interacts with other things.

People?

See the above. If some temporal accident causes me to split into two, both of those people would still be ME. (Though their cohabitating the same space would cause divergence of identity over time.) Again, this is because what I physically am is irrelevant to determining my identity (and identity is the conformance to a specific pattern).

Force fields?

"In physics a force field is a vector field that describes a non-contact force acting on a particle at various positions in space." You see that word, "acting"? To "act upon" something is quite literally definitional to being said to "interact with" a thing. By the definition I have provided of 'exists', and the definition of 'force field' as found on Wikipedia, force fields definitionally exist.

Do pebbles actually exist? But they are composed from quarks,

I refer to this as the Reductionist Problem of Scale. "Psychology isn't real because it's all just biology. Biology isn't real because it's all just chemistry. Chemistry isn't real because it's all just Physics." I don't see this as so much of a 'minefield' as a need to recognize that "scale matters". In unaided-human-observable Newtonian space, there is no question that pebbles are "totally a thing" -- they are. You can hold one in your hand. You can touch one to another one.

Of course; if you look solely at the scale of subquarks, then this distinction becomes unintelligible.

On the other hand, when I play a computer game, do the various objects in the virtual world exist?

No. Interacting with the symbol of a thing is not interacting with the thing itself. They are, however, fully real -- just like you yourself are fully real, but do not exist (you are not your body; you are not your brain; you are not the electrons and chemicals that flow through it. You are the pattern that is so-comprised. But that pattern itself is entirely non-physical in nature; it is non-instantiable and does not itself interact with anything -- nor can it ever.)

What if I write a program to play for me and stop watching the monitor. Do they stop existing?

I... am not rightly sure how you could come to the conclusion that this is a relevant question to the definition I provided. I did not say "to exist, things must be observed" -- I said "to exist, things must interact with other things". Pebbles interacting with lakes are interacting. Regardless of whether someone watches them.

If a tree falls in a forest, the tree exists. Regardless of whether it makes a sound.

• Adding \s\s before your \n will let you do newlines in Markup syntax.

Thank you.

I would be interested in knowing what resources you used for this sequence.

As an autist there is a huge swath of innate skills 'normal' people possess I can only emulate. Social success for me is indistinguishable from Dark Art skill.

Yes, but I don't think this uses the word 'exist' in the same way.

I'd say not. I tend to use two independent terms when discussing the nature of a thing's existence; I will discuss first whether or not something is real; and then whether or not that real thing exists.

To be real; a thing must be an accurate description of some pattern of behavior that things which exist conform to. (I realize this is dense/inscrutable, more in a bit.) To exist; a thing must directly interact in some fashion with other things which exist; it must be 'instantiable'.

So numbers, mathematical constructs, words; these things are real but they do not exist. We can recognize them in how the things which do exist behave. The concepts are not themselves instantiated -- ever -- but we can handle them symbolically. If I hold three pebbles in my hand, that means there is a precise arrangement of pebbles; it has a precise relationship with two the arrangement we'd call "two pebbles" and the arrangement we'd call "four pebbles" and so on. But you'll never see/hear/touch/smell/taste the number 3. It's physically impossible for that to occur; because the number, 'three', does not exist. Pebbles on the other hand do exist; you can take a pebble and throw it into a lake.

I find that this differentiation between different meanings of the term "to be" makes the discussion vastly simpler. It eliminates whole swaths of silliness (like TAG for example); I am perfectly free to say "I can prove using the Laws of Logic that the Laws of Logic do not exist."

Then you do not mean that

pleasure is the "measure of utility". That is; utility is pleasure; pleasure is utility.

Eudaimonic pleasure -- happiness -- is of a nature that wireheading would not qualify as valid happiness/pleasure. It would be like 'empty calories'; tasty but unfulfilling.

So no, I do not not mean that 'pleasure is the "measure of utility"' is the mainstream consensus view on LessWrong. I do mean that, and I believe it to be so. "Hedons" and "utilons" are used interchangeably here.