Humans can be recognized inductively: Pick a time such as the present when it is not common to manipulate genomes. Define a human to be everyone genetically human at that time, plus all descendants who resulted from the naturally occurring process, along with some constraints on the life from conception to the present to rule out various kinds of manipulation.

Or maybe just say that the humans are the genetic humans at the start time, and that's all. Caring for the initial set of humans should lead to caring for their descendants because humans care about their descendants, so if you're doing FAI you're done. If you want to recognize humans for some other purpose this may not be sufficient.

Predicting human behavior seems harder than recognizing humans, so it seems to me that you're presupposing the solution of a hard problem in order to solve an easy problem.

An entirely separate problem is that if you train to discover what humans would do in one situation and then stop training and then use the trained inference scheme in new situations, you're open to the objection that the new situations might be outside the domain covered by the original training.

Thank you. I mean the looted ones too, I don't think everybody knows about them.

For example, here is a technique I always thought it should exist and simply cannot find it, nowhere at all, maybe it doesn't or maybe I am just really missing something: I have always thought that with something like rapid breathing I should be able to stimulate my central nervous system the way say amphetamines do it, to temporarily be quicker thinking, physically faster, and ignore fatigue, it would be handy in many situations, really this is something that probably exists because if the CNS can be stimulated at all then probably not only through chems, and I am probably just overlooking something. Maybe there is a tribal people somewhere who do this jumping up and down and chanting, calling it a sacred rage induced by the war god or something.

Are there toy models of, say, a very simple universe and an AIXItl-type reasoner in it? How complex does the universe have to be to support AIXI? Game-of-life-complex? Chess-complex? D&D complex? How would one tell?

Is getting a job in programming really contingent on your getting the degree, or rather on you being capable of doing the job?

I have experienced consequences of donating blood too often.The blood donation places check your hemoglobin, but I have experienced iron deficiency symptoms when my hemoglobin was normal and my serum ferritin was low. The symptoms were twitchy legs when I was trying to sleep and insomnia, and iron deficiency was confirmed with a ferritin test. The iron deficiency symptoms went away and ferritin went back to normal when I took iron supplements and stopped donating blood, and I stopped the iron supplements after the normal ferritin test.

The blood donation places will encourage you to donate every 2 months, and according to a research paper I found when I was having this problem essentially everyone will have low serum ferritin if they do that for two years.

I have no reason to disagree with the OP's recommendation of donating blood every year or two.

The argument you made was that copy-and-destroy is not bad because a world where that is done is not worse than our own. In turn, your belief that it is not worse than our own is, as far as I can tell, based on the belief that you can compare that world to our own by comparing whether it is good for the people who remain alive, and ignoring whether it is good for the people who are killed. This implies that the fact that the person is killed doesn't count towards making the world worse because being dead, he can't know that he has been harmed, and because the other people don't feel the loss they would feel that goes with a normal death. This amounts to blissful ignorance (although I suppose the dead person can be more accurately described as having 'uncaring ignorance', since dead people aren't very blissful).

Check out Argumentum ad Populum. With all the references to "most people", you seem to be committing that fallacy so often that I am unable to identify anything else in what you say.

Pointing out that your definition of something, like harm, is shared by few people is not argumentum ad populum, it's pointing out that you are trying to sound like you're talking about something people care about but you're really not.

"Most of us think X is bad" is perhaps true for the person-copying scheme

I'm not saying that most people think this scheme is bad, I'm saying that most people don't have the definition of harm that you do. Your idea that all harm must be knowing is not one commonly shared.

And the example has nothing to do with paternity. Most people would think that a world where people are cheated on but it is not discovered is one where the other partner is being harmed, simply because cheating on someone harms them and harm does not have to be knowing in order to be harm. Or, as I summarized, most people don't think blissful ignorance is a good thing.

This reasoning can be used to justify almost any form of "what you don't know won't hurt you". For instance, a world where people cheated on their spouse but it was never discovered would function, from the point of view of everyone, as well as or better than the similar world where they remained faithful.

Most of us think the former world is bad and, if pressed, would explain it by saying that blissful ignorance is not a good thing. Even though "my spouse cheats on me but I don't know it" and "my spouse doesn't cheat on me" are indistinguishable, I have been harmed in the former situation.

Whether you call it life or death is a choice, just as any other decision to use one word or another to describe a situation is a choice.

OTOH, some such choices are worse than others.

Suppose we define a generalized version of Solomonoff Induction based on some second-order logic. The truth predicate for this logic can’t be defined within the logic and therefore a device that can decide the truth value of arbitrary statements in this logical has no finite description within this logic. If an alien claimed to have such a device, this generalized Solomonoff induction would assign the hypothesis that they're telling the truth zero probability, whereas we would assign it some small but positive probability.

I'm not sure I understand you correctly, but there are two immediate problems with this:

• If the goal is to figure out how useful Solomonoff induction is, then "a generalized version of Solomonoff Induction based on some second-order logic" is not relevant. We don't need random generalizations of Solomonoff induction to work in order to decide whether Solomonoff induction works. I think this is repairable, see below.
• Whether the alien has a device that does such-and-such is not a property of the world, so Solomonoff induction does not assign a probability to it. At any given time, all you have observed is the behavior of the device for some finite past, and perhaps what the inside of the device looks like, if you get to see. Any finite amount of past observations will be assigned positive probability by the universal prior so there is never a moment when you encounter a contradiction.

If I understand your issue right, you can explore the same issue using stock Solomonoff induction: What happens if an alien shows up with a device that produces some uncomputable result? The prior probability of the present situation will become progressively smaller as you make more observations and asymptotically approach zero. If we assume quantum mechanics really is nondeterministic, that will be the normal case anyway, so nothing special is happening here.