Yeah, it’s important what we do… but let’s not misname it:
See more of Thad’s work here.
Hi, I’m new here, but I feel that you’ve made this blog just for me.
Great! It is just for you. (Just don’t tell the other readers I said that. It’s just for them too, you see.)
Sit down and stay awhile and look around, and do come back and chat with us…
determinism is always a point that bothers people because they think it interferes with the notion of ‘free will’. the question here is if determinism is how the world works, then does it make a difference whether or not we know it? I.e. I could tell you now that it is already clear what your answer to this comment will be. In fact, it was already determined what you would answer the day you were born. does that knowledge change the answer, or your perception of having a ‘free will’? and does it make a difference for me, since I don’t know your answer – determined or not?
The benefit/downside of believing in complete determinism is that on the upside you don’t have to feel guilty anymore. On the downside you are not responsible.
But… Since I “perceive” that I have free will, I am not off the hook.
Apricot upside-down cake?
Sorry, Bee. Predictably, I tried to go for the unexpected answer.
Hi Clifford: predictably, I was looking forward to the unpredictable – it doesn’t matter whether our universe is ‘in principle’ deterministic if we can not predict it anyhow. that is to say, should someone prove tomorrow the collapse of the wave-functions is deterministic, it wouldn’t change anything about how nature has worked all the time.
Hi Elliot: that issue is actually more serious than you make it sound. you find exactly this tendency in justice today. see, that guy who raped dozens of small girls, he is a victim of his childhood and toxic tap water, right? I believe we are responsible for everything we do – one can discuss though what the appropriate means are to deal with those who make decisions that are in conflict with our societies values (i.e. whether you put them in a hospital or in jail).
Hi Bee. I predicted that you’d predict that I’d try to give an unpredictable answer.
On a more serious, but no less playful note, I’ve always thought that it would be interesting to have a universe where the laws of physics could be changed by our perceptions or awareness of them. Or better put, some of the aspects of physical law require -or are dependent- upon our perceptions and understanding of them. I’m not talking about the old measurement problem issue – discussed to death – but something (admittedly akin) that runs a lot more deeply, or at least has more (arguably) dramatic consequences. Handled the right way, that could be really interesting to think about -and would make a basis for wonderful fiction plots too. For years, I’ve been thinking that I really must get around to writing some of that. Sigh.
Interesting you chose that example of the justice system. How about the fact that a black male in America is much more likely to go to prison than his white counterpart for the same crime. Is his sentence “determined” at birth by the color of his skin?
Hi Elliot: You are talking about the ‘likeliness’ about which one can make statements whether or not the ‘fundamental’ theory is deterministic or not. According to the present status of our theoretical understanding the ‘fundamental’ theory of nature is not deterministic and the answer to your question is no, it is not determined. If you happen not to believe in quantum mechanics, and are convinced everything is deterministic, well, then it is “determined”. The actual problem however is why the probability distribution is how it is.
Hi Clifford: You mean, like the Matrix…?
No… not like the Matrix.
I am a layman but here is what I think:
A fundamental theory could predict absolutely everything about the universe in principle, but it would take nearly infinite computational power(which humans will never achieve).
If you believe that the fundamental theory is quantum, exactly this can not be the case, because it’s not deterministic. So you’re with Laplace:
“We may regard the present state of the universe as the effect of its past and the cause of its future. An intellect which at a certain moment would know all forces that set nature in motion, and all positions of all items of which nature is composed, if this intellect were also vast enough to submit these data to analysis, it would embrace in a single formula the movements of the greatest bodies of the universe and those of the tiniest atom; for such an intellect nothing would be uncertain and the future just like the past would be present before its eyes.” ~ Laplace
From what I read about quantum theory, particles in a quantum system don’t even have a definite position. From that, I’m guessing that calculating the exact position of a particle would be calculating more than everything, not exactly everything.
yes, the point is that quantum mechanics tells you there are observables that have no distinct value prior to measurement and the outcome of a measurement can not be computed, even if you’d have all possible data about everything else. You write A fundamental theory could predict absolutely everything about the universe in principle, but it would take nearly infinite computational power. This is exactly what is not possible any more. Within quantum mechanics, you can not predict absolutely everything (like e.g. exactly when does the atom decay?) even with infinite computational power. The only thing you get are probabilities. Best,
Isn’t your idea similar to Wheeler’s ‘participatory’ universe.
Also discussions about determinsim/indeterminsim implicitly assume causality and time being one dimensional without the option of time reversal. Now I strongly believe that time is one way and that causality holds but the discussion what the ‘fundamental’ theory ought to consider at least the possibliity of causal loops.
pineapple right-side up cake???
last sentence poorly worded correction:
…a discussion of what ‘the fundamental theory’ might be should at least consider the possibility of causal loops.
I can’t make sense out of what you write. For a deterministic theory, it doesn’t matter whether you can go in loops, no matter if time or spacelike. if you come back to the same point, it’s the same point, same initial conditions, or it isn’t, then it isn’t. It’s the concept of causality that goes bye-bye in this case, not determinism.
I’m sorry if I am not clear. However if you sacrifice causality, I believe you are going to have a hard time doing any science at all.
Yes, indeed, I fully agree. In this regard, you might find the paper I mentioned here interesting. To clarify what I meant: you wrote discussions about determinsim/indeterminsim implicitly assume causality and [...] ought to consider at least the possibliity of causal loops. What I tried to say is that determinism without causality doesn’t make sense. If a theory is deterministic, there is no ‘branching’ into different histories or something. You start with an initial condition, the evolution is known. If you go back to this point (if you could), the initial condition is the same, and the evolution remains the same. Now if you think about that from a microscopic point of view you can ask what is the actual meaning of causality beyond determinism, because you could as easily take an initial condition and ‘determine’ backwards. It’s here where the whole discussion about the arrow of time enters, but that’s a different story.
The bottomline is, unlike what you wrote above (without the option of time reversal) a deterministic theory has of course the option of time reversal.
Have you ever considered spacetimes with CTCs (Closed Timelike Curves) in the presence of quantum field theory? Such spacetimes (or at least a large class of them) seem to be unstable, and presumably doomed.
Thank you for the clarification.
For the record I do not believe in either time reversal or determinsim. (but what I believe and how the world works may be two different things )
Always glad to be of help. I happen to believe in determinism but am having a hard time doing so.
I haven’t really considered it, but I tend to believe it. It seems to me one would run into a problem with defining a sensible vacuum? Either way, I found the notion of causality is in many cases discussed in a rather confused way, but I certainly see no reason to give it up.
You obviously believe in determinism because you don’t have the choice to believe otherwise.
Closed Timelike Curves potentially provide a radical alternative the the “anthropic multiverse landscape” scenario (if I may call it that) In the case of CTC the current universe is bio-friendly because we’ve had a gazillion “do-overs” to get it right. Instead of many universes, one universe many times.
I agree with Bee that determinism does not matter in practice. And if a multiverse exists then you can have a deteministic world which is nevertheless non-deterministic from the point of view of observers. E.g. quantum mechanics without wavefunction collapse is deterministic…
Suppose that Bee is thinking about responding to a posting here or not to do that. Now Bee has an infinite number of copies in the multiverse. She cannot locate herself precisely in the Multiverse, because all the information stored in her brain does not single out one particular copy of her.
The amount of information needed to specify the precise way all your neurons are connected to each other is far more than the amount of information you can be consciously aware of. Therefore Bee’s own consciousness may be compatible with copies of her that will respond to a post and to copies that won’t.
These copies generate the same consciousness until the moment they decide whether or not to post here. The Bees that decide not to post have the feeling that they chose not to post and that they could have made a different choice. That is then a correct statement, because she evolved from a copy that from her point of view was exactly identical to copies who would post here (actually they will post on copies of Asymptotia on copies of Earth).
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