If computation doesn't exist because it's "a linguistic abstraction of things that exist within physics", then CPUs, apples, oranges, qualia, "physical media" and people don't exist; all of those things are also linguistic abstractions of things that exist within physics. Physics is made of things like quarks and leptons, not apples and qualia. I don't think this definition of existence is particularly useful in context.

Not quite reductionist enough, actually: physics is made of the relationship rules between configurations of spacetime which exist independently of any formal model of them that give us concepts like "quark" and "lepton". But digging deeper into this linguistic rathole won't clarify my point any further, so I'll drop this line of argument.

As to your fruit analogy: two apples do in fact produce the same qualia as two oranges, with respect to number! Obviously color, smell, etc. are different, but in both cases I have the experience of seeing two objects. And if I'm trying to do sums by putting apples or oranges together, substituting one for the other will give the same result. In comparing my brain to a hypothetical simulation of my brain running on a microchip, I would claim a number of differences (weight, moisture content, smell...), but I hold that what makes me me would be present in either one.

If you started perceiving two apples identically to the way you perceive two oranges, without noticing their difference in weight, smell, etc., then you or at least others around you would conclude that you were quite ill. What is your justification for believing that being unable to distinguish between things that are "computationally identical" would leave you any healthier?

A sufficiently advanced simulation on any substrate would have this property - the simulated qualia would feed back on the simulated world.

Correct, but both still are just simulated. The qualia that are actually occurring are those associated with the simulator substrate, not those associated with the simulated world, and in the context of the simulated world, they would not make sense.

"Qualia are not pure "outputs": they feed back on the rest of the world."

A sufficiently advanced simulation on any substrate would have this property - the simulated qualia would feed back on the simulated world.

Maybe the qualia of people who ACTUALLY have bodies are completely different from yours, a person who has no body.

I deleted this post. I will write another post later about why I deleted it.

if you're going to share incredibly personal details about "a friend"... we need to know if this information has been posted with her consent.

I think (or, anyway, hope) what you meant to write was "you need her consent before posting", rather than "we need to know whether you obtained her consent [so that we can socially penalize you if it turns out you didn't]."

I am alarmed and dismayed that no-one has raised the issue of privacy in this thread. Swimmer963, just from glancing through your comments, you're [rot13'd description of Swimmer963 deleted].

I didn't whizz through those to be creepy (actually I was impressed at how you seem to be consistently sensible), but if you're going to share incredibly personal details about "a friend" who was raped, we need to know if this information has been posted with her consent. The above is very easily enough to personally identify you.

On whether or not this will be important or not: [blanked].

EDIT: Deleted precis of Swimmer963's situation; it had served its purpose. EDIT: Deleted some personal information.

DV. I've pretty much lost patience with posts that attribute male gender to idealised agents. Destroyed my interest in rest of post.

No, then too.

For me to argue further would be to argue the meaning of "failure" in this context, when I'm pretty sure I actually agree with you on all of the substance of our posts.

I really do not want to argue about semantics either, but our agreed interpretation makes Niel's statement equivalent to "our visual system is not optimal for non-ancestral environments", which is highly uninteresting. I think the Dawkin's larengyal nerve example is much more interesting in this sense, since it points out body designs do not come from a sane Creator, at least in some instances (which is enough for his point).

If everyone was to take Landsburg's argument seriously, which would imply that all humans were rational, then everyone would solely donate to the SIAI. If everyone only donated to the SIAI, would something like Wikipedia even exist? I suppose the SIAI would have created Wikipedia if it was necessary. I'm just wondering how much important stuff out there was spawned by irrational contributions and how the world would look like if such contributions would have never been made. I'm also not sure how venture capitalist growth funding differs from the idea to diversify one's contributions to charity.

Note that I do not doubt the correctness of Landsburg's math. I'm just not sure if it would have worked out given human shortcomings (even if everyone was maximally rational). If nobody was to diversify, contributing to what seems to be the most rational option given the current data, then being wrong would be a catastrophe. Even maximally rational humans can fail after all. This wouldn't likely be a problem if everyone contributed to a goal that could be verified rather quickly, but something like the SIAI could eat up the resources of the planet and still turn out to be not even wrong in the end. Since everyone would have concentrated on that one goal (no doubt being the most rational choice at the moment), might such a counterfactual world have been better off diversifying its contributions or would the SIAI have turned into some kind of financial management allocating those contributions and subsequently become itself a venture capitalist?