The overall framework is sensible, but I have trouble applying it to the most vexing cases: where the respected elites mostly just giggle at a claim and seem to refuse to even think about reasons for or against it, but instead just confidently reject it. It might seem to me that their usual intellectual standards would require that they engage in such reasoning, but the fact that they do not in fact think that appropriate in this case is evidence of something. But what?

If the difference is between inference from surface features vs. internal structure, then yes of course in either case unless you have a very strong theory, you will probably do better to combine many weak theories. When looking at surface features, look at many different features, not just one.

I'm not sure the point of outlining a research program in an area where you are not an expert and there are now many experts. First you just want to find out what the current experts think they know. Then if you want to know more, I'd think you'd either want to ask those experts to outline a research program, or you'd want to become an expert yourself and then outline a program.

This post has not at all misunderstood my suggestion from long ago, though I don't think I thought about it very much at the time. I agree with the thrust of the post that a leverage factor seems to deal with the basic problem, though of course I'm also somewhat expecting more scenarios to be proposed to upset the apparent resolution soon.

The brain has redundancy at the level of neurons: it is quite resilient against diffuse neuron loss, and in case of localized damage, unless the affected area is large or includes key regions such as the brainstem, impairment is often limited to one or a few functions, and in some cases it even reorganizes to transfer the lost functions to other areas, partially recovering them.

However, there is no expectation that the brain has redundancy against the loss of an information storage medium that is used in all neurons.

If you destroy half of your collection of DVDs, the information in the other half is still intact. If you destroy every odd-numbered track on all of your DVDs, instead, most of the remaining data will be too fragmentary to be of any use, even if the number of bits you destroyed is the same in both cases.

Ok, now we are squeezing a comment way too far. Let me give you a fuller view: I am a neuroscientist, and I specialize in the biochemistry/biophysics of the synapse (and interactions with ER and mitochondria there). I also work on membranes and the effect on lipid composition in the opposing leaflets for all the organelles involved.

Looking at what happens during cryonics, I do not see any physically possible way this damage could ever be repaired. Reading the structure and "downloading it" is impossible, since many aspects of synaptic strength and connectivity are irretrievably lost as soon as the synaptic membrane gets distorted. You can't simply replace unfolded proteins, since their relative position and concentration (and modification, and current status in several different signalling pathways) determines what happens to the signals that go through that synapse; you would have to replace them manually, which is a) impossible to do without destroying surrounding membrane, and b) would take thousands of years at best, even if you assume maximally efficient robots doing it (during which period molecular drift would undo the previous work).

Etc, etc. I can't even begin to cover complications I see as soon as I look at what's happening here. I'm all for life extension, I just don't think cryonics is a viable way to accomplish it.

Instead of writing a series of posts in which I explain this in detail, I asked a quick side question, wondering whether there is some research into this I'm unaware of.

Does this clarify things a bit?

Don't confuse cryobiology with cryonics. Cryobiologists, the people who actually invent these tissue preservation techniques which are routinely used in hospitals and research labs all over the world, typically think that cryonics is a pseudoscience at best and a fraud at worst: http://en.wikipedia.org/wiki/Cryobiology#Scientific_societies

Reversible vitrification of individual cells or small samples of tissue is possible because they are small, thus they can be cooled quickly. Cryoprotectants are used to facilitate the process, but not in toxic concentrations.

Fast cooling of objects as large as a human body, or even a human head, is essentially impossible due to the square-cube law: the thermal capacity of an object is proportional to its mass, which, for a given density, is proportional to its volume, while its capacity to transfer heat is proportional to its surface area. As size increases, surface area grows quadratically while volume grows cubically, hence their ratio decreases.

If you attempt to cool a large object too fast, you will freeze or vitrify only a thin superficial layer, and probably even shatter it, since temperature gradients cause gradients of thermal contraction resulting in mechanical stress.

Cryonicists who attempt to preserve whole human cadavers or heads, perfuse them with large amounts of cryoprotectants in order to achieve vitrification. This has several problems:

• In contrast with mainstream tissue preservation techniques, cryonicists use cryoprotectants in toxic concentrations. At these concentrations, unreversible damage occurs: proteins become denaturated and cell membranes become distorted.
• Cryoprotectants are perfused post-mortem. It's unclear how deep they are actually able to diffuse. Any area where cryoprotectants don't reach the concentration required for vitrification will be destroyed by ice crystal formation. So far, no cryopreserved human brain has ever been examined to determine the extent of freezing damage.
• The cryoprotectant perfusion process and the subsequent cooling are very slow. Typically, at least two days pass between the someone's terminal cardiac arrest and the time they reach glass transition temperature, during much of this time their brain has no significant oxygen and glucose supply (ischemia). Human nervous tissue is typically unrecoverably damaged after about one hour of ischemia.
• For ease of storage, cryonicists cool cadavers past the glass transition temperature, down to liquid nitrogen temperature. Since different types of tissues in the human body thermally contract at different rates, mechanical stress causes multiple widespread macroscopic fractures in all organs including the brain. The extent of microscopic damage at the edges of these fractures is unknown.

The point: Not that a vast mansion will be too difficult to simulate relative to a smelly hut, but that anything simulated in sufficient detail will become luxury, while non-wealthy ems live in the relative squalor of palatial mansions that just don't look/feel/sound/smell quite right, in an unpleasant way.

That doesn't make intuitive sense to me. Surely even fast ems living in cheap real estate will still have plenty (millions? billions?) of people to talk to in real time, even if they have fewer people to talk to compared to those living in prime real estate? Given that running slower has significant costs (you have to pay the same storage costs as faster ems but can do less work, not being able to accumulate experience/knowledge as fast as others and losing competitive edge as a result) I don't see how it's worth those costs just to have more potential people to talk to.

Also, if you're assuming that it's fairly cheap to speed up and slow down emulations, which you apparently are, why don't they run at a fast speed normally and only slow down when they need to talk to distant others with low subjective latency, which may be pretty rare?

Just a rough dirty outline since I'm headed out of town for two days. I may make a discussion post about some of the points later.

• The natural human method of property division is killing people and taking their stuff. Capitalism is a blip on the radar.

• Ems will be entering an entirely different context than 20th century humans. We'll be lucky if capitalism translates to the digital world at all.

• Ems vs human will be a natural division point. Every human (if lucky) becomes a retiree at some point, no Ems become human. Humans do not have a good track record of respecting the property rights of those different to them.

• Humans literally cannot object to Ems doing this. We literally cannot think fast enough to stop it from happening and it only needs happen once in 5000 years each year for us.

• 5000 years? That's older than the entire concept of capital. Unless capitalism is the one true economic system for all eternity, you'll be out of luck. Historically, the vast majority of economic systems wouldn't honor your holding onto that property without a means to personally enforce it.

• 5000x wasn't the cap. Hanson made a comment about potential 1,000,000x speeds. One year goes longer back than our ancestors could even say the word 'capitalism'. I say ancestors because homo sapiens weren't around back then. I'm imagining making a capital investment to Krogg, and trying to get that repaid today.

• This ignores the possibility of Em-space becoming a free for all of replicators trying to ascend into Godhood. I consider it the most likely possibility (but that's the subject of another thread). But even if that doesn't happen and they keep capitalism, and Ems have no government shakeups, and they bother keeping track of debts to humans, you won't be able to withdraw because...

• Sheer magnitude of value. A human working earning, lets say $20,000 in one year pre-uploading, is worth one man-year of work. A human investing that money and earning a year's interest during the 1-month doubling time frame suddenly has $81,000,000. People would happily steal from retirees if that much money was changing hands.

• Meanwhile the average wage has dropped to $4 a year. There is no moral system I can imagine that figures it's okay for one person's year of work to be worth someone else's 20-million years of work just because they got lucky when they made it.

• Scratch that. I know that there's a similar-ish disparity between a CEO and a bottom quintile Nigerian. Lucky for the CEO, current Nigerians don't run at 5000x speed because they would happily take his money away and be morally okay with that. Lets say some Ems are on the side of giving humans back their money. You're going to have literally a thousand times the current population of the earth as poor Nigerians who will be set for a literal million years if they can get just a fraction of the money away from the old human dinosaurs who literally cannot object to them. That's a lot of literals.

• Similarly, the opportunity cost of 'pay off that human' vs 'give 10,000,000 ems a better standard of living' is an easy choice. Who could morally side with the human? Well, maybe a human but they won't be making that decision.

• All the goods are digital. You can't eat zeros and ones. Your money will increase by 4,000x+ a year, but the number of apples won't increase by 4,000x+ a year, so the gains will just be inflated away for physical goods.

• Actually, the economy will probably become mostly decoupled between digital and physical goods. Ems may increase thinking capacity a trillion fold, but it's not they'll will significantly increase the number of apples we grow.

• Scratch that. Having Ems will increase apples, because all the computer programmers, and bureaucrats, and entertainers, and etc, etc, etc, will now be out of jobs except for growing apples and delivering microchips to the Em towers. So, I guess that's nice?

My original post was expressing derision at the idea that you could live off the interest from Ems. I understand that it's not a popular message to say, "Ems are gonna hard takeoff, and leave us in the dust, but we won't necessarily go extinct (unless we do)." However, it's a lot more honest than promising fantastic wealth just for surviving until uploading even if you yourself don't upload. As I mentioned above these are rough objections, but I may make a post.