Radford Neal
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Radford Neal has not written any posts yet.
Radford Neal has not written any posts yet.
Regarding cloning, we have very good reason to think that good-enough memory erasure is possible, because this sort of thing happens in reality - we do forget things, and we forget all events after some traumas. Moreover, there are plausible paths to creating a suitable drug. For example, it could be that newly-created memories in the hippocampus are stored in molecular structures that do not have various side-chains that accumulate with time, so a drug that just destroyed the molecules without these side-chains would erase recent memories, but not older ones. Such a drug could very well exist even if consciousness has a quantum aspect to it that would... (read more)
I don't think the issue of whether "cloning" is possible is actually crucial for this discussion, but since this relates to a common lesswrong sort of assumption, I'll elaborate on it. I do think that making a sufficiently accurate copy is probably possible in principle (but obviously not now, and perhaps never, in practice). However, I don't think this has been established. It seems conceivable that quantum effects are crucial to consciousness - certainly physics gives us no fundamental reason to rule this out. If this is true, then "cloning" (not the usual use of the word) by measuring the state of someone's body and then constructing... (read 525 more words →)
"The probability of me being a man" in the anthropic sense means the probability of me being born into this world as a human male. Or it can been seen as the probability of my soul getting embodied as a human male. ... even though "I'm a man" is a valid statement "the probability of me being a man" does not exist
Here, you have imported some highly questionable ideas, which would seem to be not at all necessary for analysing the Sleeping Beauty problem. This is my core objection to how Sleeping Beauty is used - it's an almost-non-fantastical problem that people take to have implications for these sorts of anthropic... (read 726 more words →)
I'm afraid this makes no sense to me. I think this comes from my not understanding how the concept of a "reference class" can possible work. So I have no idea what it could mean to "observe the world from the perspective of any human that is male", if observing from that "perspective" is supposed to change the probability (or render the probability meaningless) of some statement that I would take to be about the actual, real, world.
As I've pointed out before, the Sleeping Beauty problem is only barely a thought experiment - with a slight improvement over current memory-affecting drugs, it would be possible to actually run the experiment.... (read 534 more words →)
This is because in the context of sleeping beauty problem the probabilities of “today being Monday/Tuesday” do not exist. In another word “what’s the probability of today being Monday/Tuesday” are invalid questions.
I think here you depart from common-sense realism, in favour of what I am not sure.
From a common-sense standpoint, it is meaningful for Beauty to consider the probability of it being Monday because she can decide to batter down the door to her room, go outside, and ask someone she encounters what day of the week it is. That she actually has no desire to do this does not render the question meaningless.
What I mean by "someone with those memories exists" is just that there exists a being who has those memories, not that I in particular have those memories. That's the "non-indexical" part of FNC. Of course, in ordinary life, as ordinarily thought of, there's no real difference, since no one but me has those memories.
I agree that one could imagine conditioning on the additional piece of "information" that it's me that has those memories, if one can actually make sense of what that means. But one of the points of my FNC paper is that this additional step is not necessary for any ordinary reasoning task, so to say it's necessary for something like evaluating cosmological theories is rather speculative. (In contrast, some people seem to think that SSA is just a simple extension of the need to account for sampling bias when reasoning about ordinary situations, which I think is not correct.)
I can sort of see what you're getting at here, but to me needing to ask "what question was being asked?" in order to do a correct analysis is really a special case of the need to condition on all information. When we know "the older child in that family is a boy", we shouldn't condition on just that fact when we actually know more, such as "I asked a neighbour whether the older child is a boy or girl, and they said 'a boy'", or "I encountered a boy in the family and asked if they were the older one, and they said 'yes'". Both these more detailed descriptions... (read more)
I'm not sure what you're saying in this reply. I read your original post as using the island problem to try to demonstrate that there are situations in which using probabilities conditional on all the available information gives the wrong answer - that to get the right answer, you must instead ignore "ad hoc" information (though how you think you can tell which information is "ad hoc" isn't clear to me). My reply was pointing out that this example is not correct - that if you do the analysis correctly, you do get the right answer when you use all the information. Hence your island problem does not provide... (read more)
As you may know, my Full Nonindexical Conditioning (FNC) approach (see http://www.cs.utoronto.ca/~radford/anth.abstract.html) uses the third-person perspective for all inference, while emphasizing the principle that all available information should be used when doing inference. In everyday problems, a third-person approach is not distinguishable from a first-person approach, since we all have an enormous amount of perceptions, both internal and external, that are with very, very high probability not the same as those of any other person. This approach leads one to dismiss the Doomsday Argument as invalid, and to adopt the Thirder position for Sleeping Beauty.
You argue against approaches like FNC by denying that one should always condition on all available information. You... (read 638 more words →)
Sleeping Beauty with cookies is an almost-realistic situation. I could easily create an analogous situation that is fully realistic (e.g., by modifying my Sailor's Child problem). Beauty will decide somehow whether or not to eat a cookie. If Beauty has no rational basis for making her decision, then I think she has no rational basis for making any decision. Denial of the existence of rationality is of course a possible position to take, but it's a position that by its nature is one that it is not profitable to try to discuss rationally.