The roundtable was at SC'08, a while after speeds had stabilized, and since it is a supercomputing conference, the focus was on massively parallel systems. It was part of this.
While the leakage issue is important and I want to read a little more about this reference, I don't think that any single such current technical issue is nearly sufficient to change the general analysis. There have always been major issues on the horizon, the question is more of the increase in engineering difficulty as we progress vs the increase in our effective intelligence and simulation capacity.
In the specific case of leakage, even if it is a problem that persists far into the future, it just slightly lowers the growth exponent as we just somewhat lower the clock speeds. And even if leakage can never be fully prevented, eventually it itself can probably be exploited for computation.
I really doubt that current-human-fun-maximization is an evolutionary stable goal system. I imagine that future posthuman morality and goals will evolve into something quite different.
Without needing to dispute this, I can remain exceptionally upset that whatever their future morality is, it is blind to suffering and willing to create innumerable beings that will suffer in order to gain historical knowledge.
As I child I liked Mcdonalds, bread, plain pizza and nothing more - all other foods were poisonous. I was convinced that my parent's denial of my right to eat these wonderful foods and condemn me to terrible suffering as a result was a sure sign of their utter lack of goodness.
Imagine if I could go back and fulfill that child's wish to reduce it's suffering. It would never then evolve into anything like my current self, and in fact may evolve into something that would suffer more or at the very least wish that it could be me.
Imagine if we could go back in time and alter our primate ancestors to reduce their suffering. The vast majority of such naive interventions would cripple their fitness and wipe out the lineage. There is probably a tiny set of sophisticated interventions that could simultaneously eliminate suffering and improve fitness, but these altered creatures would not develop into humans.
Our current existence is completely contingent on a great evolutionary epic of suffering on an astronomical scale. But suffering itself is just one little component of that vast mechanism, and forms no basis from which to judge the totality.
You made the general point earlier, which I very much agree with, about opportunity cost. Simulating humanity's current time-line has an opportunity cost in the form of some paradise that could exist in it's place. You seem to think that the paradise is clearly better, and I agree: from our current moral perspective.
In the end of the day morality is governed by evolution. There is an entire landscape of paradises that could exist, the question is what fitness advantage do they provide their creator? The more they diverge from reality, the less utility they have in advancing knowledge of reality towards closure.
It looks like earth will evolve into a vast planetary hierarchical superintelligence, but ultimately it will probably be just one of many, and still subject to evolutionary pressure.
You made the general point earlier, which I very much agree with, about opportunity cost. Simulating humanity's current time-line has an opportunity cost in the form of some paradise that could exist in it's place. You seem to think that the paradise is clearly better, and I agree: from our current moral perspective.
It seems you're arguing that our successors will develop a preference for simulating universes like ours over paradises. If that's what you're arguing, then what reason do we have to believe that this is probable?
If their preferences do not ...
Many folk here on LW take the simulation argument (in its more general forms) seriously. Many others take Singularitarianism1 seriously. Still others take Tegmark cosmology (and related big universe hypotheses) seriously. But then I see them proceed to self-describe as atheist (instead of omnitheist, theist, deist, having a predictive distribution over states of religious belief, et cetera), and many tend to be overtly dismissive of theism. Is this signalling cultural affiliation, an attempt to communicate a point estimate, or what?
I am especially confused that the theism/atheism debate is considered a closed question on Less Wrong. Eliezer's reformulations of the Problem of Evil in terms of Fun Theory provided a fresh look at theodicy, but I do not find those arguments conclusive. A look at Luke Muehlhauser's blog surprised me; the arguments against theism are just not nearly as convincing as I'd been brought up to believe2, nor nearly convincing enough to cause what I saw as massive overconfidence on the part of most atheists, aspiring rationalists or no.
It may be that theism is in the class of hypotheses that we have yet to develop a strong enough practice of rationality to handle, even if the hypothesis has non-negligible probability given our best understanding of the evidence. We are becoming adept at wielding Occam's razor, but it may be that we are still too foolhardy to wield Solomonoff's lightsaber Tegmark's Black Blade of Disaster without chopping off our own arm. The literature on cognitive biases gives us every reason to believe we are poorly equipped to reason about infinite cosmology, decision theory, the motives of superintelligences, or our place in the universe.
Due to these considerations, it is unclear if we should go ahead doing the equivalent of philosoraptorizing amidst these poorly asked questions so far outside the realm of science. This is not the sort of domain where one should tread if one is feeling insecure in one's sanity, and it is possible that no one should tread here. Human philosophers are probably not as good at philosophy as hypothetical Friendly AI philosophers (though we've seen in the cases of decision theory and utility functions that not everything can be left for the AI to solve). I don't want to stress your epistemology too much, since it's not like your immortal soul3 matters very much. Does it?
Added: By theism I do not mean the hypothesis that Jehovah created the universe. (Well, mostly.) I am talking about the possibility of agenty processes in general creating this universe, as opposed to impersonal math-like processes like cosmological natural selection.
Added: The answer to the question raised by the post is "Yes, theism is wrong, and we don't have good words for the thing that looks a lot like theism but has less unfortunate connotations, but we do know that calling it theism would be stupid." As to whether this universe gets most of its reality fluid from agenty creators... perhaps we will come back to that argument on a day with less distracting terminology on the table.
1 Of either the 'AI-go-FOOM' or 'someday we'll be able to do lots of brain emulations' variety.
2 I was never a theist, and only recently began to question some old assumptions about the likelihood of various Creators. This perhaps either lends credibility to my interest, or lends credibility to the idea that I'm insane.
3 Or the set of things that would have been translated to Archimedes by the Chronophone as the equivalent of an immortal soul (id est, whatever concept ends up being actually significant).