Person X stands in front of a sophisticated computer playing the decision game Y which allows for the following options: either press the button "sim" or "not sim". If she presses "sim", the computer will simulate X*_1, X*_2, ..., X*_1000 which are a thousand identical copies of X. All of...
I have collected some thoughts on decision theory and am wondering whether they are any good, or whether I’m just thinking non-sense. I would really appreciate some critical feedback. Please be charitable in terms of language and writing style, as I am not a native English speaker and as this...
Thanks for mentioning this. I know this wasn't put very nicely.
Imagine you were a very selfish person X only caring about yourself. If I make a really good copy of X which is then placed 100 meters next to X, then this copy X only cares about the spatiotemporal dots of what we define X. Both agents, X and X, are identical if we formalize their algorithms incorporating indexical information. If we don't do that then a disparity remains, namely that X is different to X in that, intrinsically, X only cares about the set of spatiotemporal dots constituting X. The same goes for X accordingly. But this semantical issue doesn't seem... (read more)
Person X stands in front of a sophisticated computer playing the decision game Y which allows for the following options: either press the button "sim" or "not sim". If she presses "sim", the computer will simulate X*_1, X*_2, ..., X*_1000 which are a thousand identical copies of X. All of them will face the game Y* which - from the standpoint of each X* - is indistinguishable from Y. But the simulated computers in the games Y* don't run simulations. Additionally, we know that if X presses "sim" she receives a utility of 1, but "not sim" would only lead to 0.9. If X*_i (for i=1,2,3..1000) presses "sim" she receives 0.2, with... (read 185 more words →)
It goes the other way round. An excerpt of my post (section Newcomb's Problem's problem of free will):
Perceiving time without an inherent “arrow” is not new to science and philosophy, but still, readers of this post will probably need a compelling reason why this view would be more goal-tracking. Considering the Newcomb’s Problem a reason can be given: Intuitively, the past seems much more “settled” to us than the future. But it seems to me that this notion is confounded as we often know more about the past than we know about the future. This could tempt us to project this disbalance of knowledge onto the universe such that we perceive the past as settled and unswayable in contrast to a shapeable future. However, such a conventional set of intuitions conflicts strongly with us picking only one box. These intuitions would tell us that we cannot affect the content of the box; it is already filled or empty since it has been prepared in the now inaccessible past.
Look, HIV patients who get HAART die more often (because people who get HAART are already very sick). We don't get to see the health status confounder because we don't get to observe everything we want. Given this, is HAART in fact killing people, or not?
It is not that clear to me what we know about HAART in this game. For instance, in case we know nothing about it and we only observe logical equivalences (in fact rather probabilistic tendencies) in the form "HAART" <--> "Patient dies (within a specified time interval)" and "no HAART" <--> "Patient survives" it wouldn't be irrational to reject the treatment.
Once we know more about HAART, for... (read more)
I agree that it is challenging to assign forecasting power to a study, as we're uncertain about lots of background conditions. There is forecasting power to the degree that the set A of all variables involved with previous subjects allow for predictions about the set A' of variables involved in our case. Though when we deal with Omega who is defined to make true predictions, then we need to take this forecasting power into account, no matter what the underlying mechanism is. I mean, what if Omega in Newcomb's Problem was defined to make true predictions and you don't know anything about the underlying mechanism? Wouldn't you one-box after all? Let's call... (read more)
If lots of subjects were using CDT or EDT, they would all be choosing ice cream independently of their soda, and we wouldn't see that correlation (except maybe by coincidence). So it doesn't have to be stated in the problem that other subjects aren't using evidential reasoning--it can be seen plainly from the axioms! To assume that they are reasoning as you are is to assume a contradiction.
If lots of subjects were using CDT or EDT, they would be choosing ice cream independently of their soda iff the soda has no influence on whether they argue according to CDT or EDT. It is no logical contradiction to say that the sodas might... (read 354 more words →)
Presumably, if you use E to decide in Newcomb's soda, the decisions of agents not using E are screened off, so you should only calculate the relevant probabilities using data from agents using E.
Can you show where the screening off would apply (like A screens off B from C)?
I claim EDT is irrepairably broken on far less exotic problems than Parfit's hitchhiker. Problems like "should I give drugs to patients based on the results of this observational study?"
This seems to be a matter of screening off. Once we don't prescribe drugs because of evidential reasoning we don't learn anything new about the health of the patient. I would only not prescripe the drug if a credible instance with forecasting power (for instance Omega) shows to me that generally healthy patients (who show suspicious symptoms) go to doctors who endorse evidential reasoning and unhealthy patients go to conventional causal doctors. This sounds counterintuitive, but structurally it is equal to Newcomb's Problem:... (read more)
My comment above strongly called into question whether CDT gives the right answers. Therefore I wouldn't try to reinvent CDT with a different language. For instance, in the post I suggest that we should care about "all" the outcomes, not only the one happening in the future. I've first read about this idea in Paul Almond's paper on decision theory. An excerpt that might be of interest:
... (read 705 more words →)Suppose the universe is deterministic, so that the state of the universe at any time completely determines its state at some later time. Suppose at the present time, just before time t_now, you have a choice to make. There is a cup of coffee on a table
In the post you can read that I am not endorsing plain EDT, as it seems to lose in problems like parfit's hitchhiker or counterfactual mugging. But in other games, for instance in Newcomblike problems, the fundamental trait of evidential reasoning seems to give the right answers (as long as one knows how to apply conditional independencies!). It sounds to me like a straw man that EDT should give foolish answers (pass on crucial issues like screening off so that for instance we should waste money to make it more likely that we are rich if we don't know our bank balance) or otherwise be isomorphic with CDT. I think that a... (read more)
I have collected some thoughts on decision theory and am wondering whether they are any good, or whether I’m just thinking non-sense. I would really appreciate some critical feedback. Please be charitable in terms of language and writing style, as I am not a native English speaker and as this is the first time I am writing such an essay.
I agree. It seems to me that the speciality of the Necomb Problem is that actions "influence" states and that this is the reason why the dominance principle alone isn't giving the right answer. The same applies to this game. Your action (sim or not sim) determines the probability of which agent you have been all along and therefore "influences" the states of the game, whether you are X or X*. Many people dislike this use of the word "influence" but I think there are some good reasons in favour of a broader use of it (eg. quantum entanglement).