Re: choice and the quantum
Lennart Nilsson wrote: What on earth does the following footnote mean? Are we back to consciousness where the quantumbuck stops? /LN Understanding Deutsch's Probability in a Deterministic Multiverse by Hilary Greaves Footnote 16 The following objection is sometimes raised against the decision-theoretic approach: in an Everettian context, all outcomes of a decision are realized, and therefore it simply does not make sense to make choices, or to reason about how one should act. If that is correct, then while we may agree that probability can in principle be derived from rationality, this is of no use to the Everettian, since (it is claimed) the Everettian cannot make sense of rationality itself. If this was correct, it would be a pressing 'incoherence problem' for the decision-theoretic approach. The objection, however, is simply mistaken. The mistake arises from an assumption that decisions must be modelled as Everettian branching, with each possible outcome of the decision realized on some branch. This is not true, and it is not at all what is going on in the decision scenarios Deutsch and Wallace consider. Rather, the agent is making a genuine choice between quantum games, only one of which will be realized (namely, the chosen game). To be sure, each game consists of an array of branches, all of which will, if that game is chosen, be realized. But this does not mean that all games will be realized. It is no less coherent for an Everettian to have a preference ordering over quantum games than it is for an agent in a state of classical uncertainty to have a preference ordering over classical lotteries. To me this looks like an attempt to hold onto rationality and meaning, which requires genuine choice. Modern man has been stripped of his/her rationality as a result of trying to hold onto rationalism in a closed system. But like I've said on my soapbox before, the multiverse doesn't solve this problem, it just makes it worse if anything. Actually, if we truly accept the conclusions of rationalism in a closed system, the multiverse doesn't make it worse; but it also doesn't help one iota, contrary to the hopes of its proponents. Tom Caylor
Rép : Paper+Exercises+Naming Issue
Thanks Hal. I add that your link provide a way to recover my old conversation with Joel Dobrzelewski on the list (28 June 2001), which presents the simplest version of the Universal Dovetelair Argument (UDA), i.e. the argument showing that the computationalist hypothesis (in the bio/psycho/theo/-logical sciences) entails that physics is ultimately a branch of machine bio/psycho/theo/-logy. In particular it shows that physics can be presented as a probability or credibility measure on the relative computational histories (which are computation as seen from some first person perspective). The argument is presented in a step by step way, and begins here: http://www.mail-archive.com/everything-list@eskimo.com/msg01274.html You can then follow the step by clicking on the right arrow next date, and skipping the many threads we were discussing simultaneously at that time. People interested can ask questions. Note that the lobian interview does not necessitate the understanding of the UDA, but this one provides the basic motivation for some of the Theaetetical variants of the modal logic G and G*. Bruno PS I must still verify, with G*, some assertions made by Plotinus, and reciprocally I need to verify assertions made by G* with Plotinus. To be sure I have found a discrepancy between the loebian entity and Plotinus. It seems to be a point where the neoplatonist diverge the most from Aristotle, and then apparently the loebian diverges still more. To conclude I need better translations and unabridged version of Plotinus. I need a bit more time. Le 21-janv.-06, à 00:52, Hal Finney a écrit : Here is a link to an article I wrote in 2001 explaining what the Universal Dovetailer is: http://www.mail-archive.com/everything-list@eskimo.com/msg01526.html Hal Finney http://iridia.ulb.ac.be/~marchal/
UDA and unknowability of CLOS
Bruno wrote: Thanks Hal. I add that your link provide a way to recover my old conversation with Joel Dobrzelewski on the list (28 June 2001), which presents the simplest version of the Universal Dovetelair Argument (UDA), i.e. the argument showing that the computationalist hypothesis (in the bio/psycho/theo/-logical sciences) entails that physics is ultimately a branch of machine bio/psycho/theo/-logy. In particular it shows that physics can be presented as a probability or credibility measure on the relative computational histories (which are computation as seen from some first person perspective). The argument is presented in a step by step way, and begins here: http://www.mail-archive.com/everything-list@eskimo.com/msg01274.html You can then follow the step by clicking on the right arrow next date, and skipping the many threads we were discussing simultaneously at that time. People interested can ask questions. Note that the lobian interview does not necessitate the understanding of the UDA, but this one provides the basic motivation for some of the Theaetetical variants of the modal logic G and G*. Bruno I've had this question brewing for some time while I've been pondering the UDA. So now I've gone through the above thread and I still didn't find the answer to it. In the UDA it is said that the Correct Level Of Substitution (I'll call is CLOS for short) is unknowable. I agree: Just intuitively, in a closed system, how could we know if something wasn't exactly right? It would result in the future being different than it would have been, but we wouldn't be aware of the difference. We would just accept that as reality. Since the CLOS is unknowable, then we should be able to talk about an unknowable, yet true, probability P(CLOS) that each substitution is done at the CLOS. By the way, we know at least P(CLOS) 1 because the doctor is guessing, and P(CLOS) = 1 would implies that the doctor knows and can actually implement it. But in fact I'd say that we really don't have any lower bound for P(CLOS), but that fact is beside the point I want to make. OK, so now for my question. So when we talk about finding a probability measure on the 1-determinancy (I don't know if that's the exact right words), don't we have to multiply this probability measure by the unknown P(CLOS) to get the actual probability measure? But this would imply that the probability measure is impossible to find out to any degree that would be called scientific, since it is a function of P(CLOS), i.e. the step of faith in saying Yes to the doctor who doesn't know anything. In fact, if each moment is equivalent to a substitution (not necessarily at the CLOS!), as comp says, then there would be an exponential decay of our identity, as sort of identity entropy. Tom Caylor
