Thankfully, you have already got your answer from the GQ thread you started:
And that is, of course, exactly what I said in this thread.*
Moreover, and very important:
You should not be so terribly eager to assume that the physicists who said they favored the MWI, and also said that randomness was irreducible, do not believe that the MWI is deterministic exactly as defined. Determinism is a very easily defined word, but the same ease applies neither to “random” nor “irreducible”. I’m not exactly sure what they mean when they talk about irreducible randomness, and in my opinion, you should not be so (seemingly?) sure of what they mean either. Depending on their definitions, they could very easily acknowledge causal determinism while also approaching randomness in personal, idiosyncratic ways.
*(I want to commend you, by the way, for opening that thread. I’ve had conversations in the past which simplified to a basic GQ style of question, and the other poster, rather than taking the effort to actually gain more information about the simple matter of fact they were literally just making assertions about, instead said something along the lines of “Well, I’m not going trust on economist on that, derpy derpy derp.” Curiosity is an important trait, and it’s always admirable to make oneself more knowledgeable about a topic rather than summarily dismissing something because it comes from a strange source. I admire that.)
I’ll return to defining “decision” either tomorrow or the day after.
I didn’t say it was being the entity.
I said it was being the entity’s mind.
Even in parens, that is not a word to be ignored.
Unfortunately, for now I’m going to have to leave this particular topic of conversation where it lies.
I actually haven’t been trying to convince anyone that it is.
Rather, I have been trying to explain how a causally deterministic universe is potentially consistent with what we perceive. Not that determinism must be the case, but that it legitimately could be the case. Many of these threads – maybe most, and maybe even all of these threads – get caught on the notion in some people’s heads that “determinism” (however strangely they define that word) cannot possibly explain events as we see them unfold in front of us.
I didn’t enter this thread to argue for a deterministic worldview. I entered this thread to define determinism in a way that might be actually clear for people, so the worst of the objections to the idea could finally be dismissed.
And I see right now that my major mistake in this thread was trying to answer your questions about whether I believed this universe was actually deterministic. I mentioned time and again that I wasn’t certain of anything, but after that, I gave my own opinion and said sure, I think it is. I pointed out it would take a much longer post to make even a bad argument in favor of that.
I have not even once been trying to make this much longer argument. I’ve just been trying to answer honestly whatever questions about determinism you offered up. And now you write here you think the universe is probably not deterministic.
I think we all knew that already.
If I actually wanted to argue in favor of determinism, each of my posts would be about ten times longer than it currently is. That might sound like a joke, but it isn’t. It might actually be an underestimate. I was trying to spare the people here the tedium of experiencing that, by giving them the lesser tedium of answering your questions honestly in a (for me) brief space. But even that seems to have been too tedious for this particular context.
I’m not going to do that anymore here. I’m not going to answer questions about qualia, or simulating a mind vs being a mind, or anything along those lines. They’re a digression that seem to be taken for an argument.
From here on, I will answer questions about the definition and implications of causal determinism only. Most importantly for this thread, this includes the definition of “decision” within a deterministic system. But most of the other stuff that is bothering people, I’m going to stop with right now. So, in an attempt to return to defining determinism and exploring its implications…
I want to be very clear here.
The MWI does potentially make “predictions” that differ from the other interpretations… from the perspective of a very small subset of individuals. What it does not offer is predictions that can be printed up in a scientific journal. One such prediction can be seen in the idea of quantum immortality.
This idea is very frightening to some people, so anyone who is a bit squeamish might want to stop reading now.
If you wanted a very, very, very small subset of your selves in various worlds to know for pretty much certain whether they lived in an MWI universe (conditional on the very important possibility that they actually did live in such a universe), you could set up a gun pointed at your head, hooked up to a quantum event. Before you tested on yourself, you would want to make sure the equipment worked. Have the mechanism hooked up so that quantum event 1 fired the gun, and quantum event 0 did not fire the gun, and then run the event 1000 times, so that on average the gun fires 500 times (or whatever) over the course of the 1000 trials.
You could then aim the gun at your head and run it (potentially) 1000 more times.
If the first trial aimed not at your head looks something like 0111010010111010010, with the gun often firing, and…
if the second trial looks something like 0000000000000000000, so that you never seem to get shot in the head…
then that can inform the one survivor of the experience of the underlying reality. At the expense of countless other murders. This is obviously a highly unethical experiment. No one else in the scientific community could repeat the experiment in a way that you were likely to verify. But it does make an unambiguous prediction that can potentially be confirmed for a small subset of people. (It does not make a prediction that can be rejected for even a small subset of people, since things turn out very badly for every version of you, instead of merely 99.999% of the copies of you, if the idea is wrong.)
And what is even more disturbing for some people is (again, not for the squeamish) our very lives are very similar to this experiment. We walk around every day, and it’s quite possible that the gun sees a 1 for certain versions of ourselves. Every day. But that also means the gun sees a 0 for others, and that might continue for the survivors. Forever.
Now, physicists don’t tend to call things like that a “prediction” because they can’t publish a paper on it.
But there is nevertheless the distinct possibility that this is relevant to your future life experiences (for a very, very, very small subset of “you”). If you’ve ever 250 years old and thinking back on this conversation, I would strongly suggest that you change your mind on the deterministic nature of the universe.
And that brings me to “shut up and calculate”.
I do not believe that every single person who has ever spoken that phrase is narrow-minded. Absolutely not. (I have already tried to clarify this, yet you still decided to ask that sort of the IMHO question at the end of your GQ thread, so it seems prudent to clarify. Again.) But here is the point.
The world is what it is.
If it’s deterministic, then it is not remotely interested in your relative disbelief about that. The world is what it is. It follows whatever rules it follows. (Or maybe in your view, it follows whatever non-rules it follows.) However it works, I believe that intellectually curious people should have some interest in the question. We are, after all, talking about one of the fundamental questions of reality. How does this world actually work at a core level? Can we figure that out? And if we can, what answer should we accept?
There are some physicists that say “show up and calculate”. And if you ask (some of them, not all of them) why they do that, they say, “Well, I’m trying to do physics. Worrying about which interpretation is correct is philosophy, not physics.” And okay, I can roll with that. I don’t quite define those two words in that way, but okay. But then, more than once, the next sentence out of their mouths has been something like, “And I don’t care about philosophy.” And notice right there that they’re saying that the question of how the physics of our world actually works is a question that not only does not belong to science (!) but also a question that doesn’t even interest them (!!!).
To this day, that is one of the most intellectually chickenshit positions I have ever come across in my life.
I don’t listen to this sort of conversation often, which means I haven’t heard this sort of thing often. And (of course!) it’s not from literally everyone who says they like to “shut up and calculate”. But the two are definitely correlated strong enough that even that phrase – which is potentially innocuous on its own – still sets my teeth on edge.
It makes perfect sense for scientists to focus on the kinds of questions that they can share with the rest of the scientific community. In that case, something like which interpretation is true is not “scientific” precisely because the result of an unethical experiment could not be repeated by others across the world to confirm it. That’s a perfectly acceptable definition of science. (Not mine, but fine.) It’s not that these people aren’t interested in the question, or that they don’t think it’s important. Not at all. It’s that they think the question lies outside their profession as they practice it. “Shut up and calculate” makes a certain sense in that context.
But to add on top of that that they don’t even care about the question, well, there is a huge difference there.
I would hope that all of my points relating to the bare definition of determinism is clear.
I definitely made a big mistake leaving that topic and trying to discuss whether this particular world is deterministic.
For the record, I think yours are consistently the best posts in these sorts of threads.