I used to trivialise the simulation hypothesis but since I came across Boltzmann Brain everything is starting to click piece by piece

Maybe the universe is just one colossal quantum computer

Ok move to science section

Explain in depth

The "Boltzmann brain" isn't really anything. It's a thought experiment in thermodynamics created to explore an interesting and complex question.

Thermodynamics is basically the study of heat and the flow of heat. Heat is a property of matter — it's got to do with energy on very small scales — but it behaves like it's a kind of fluid, moving from place to place across gradients the way water flows downhill. Since literally all work in the universe is a function of the flow of heat, a lot of work's been done on the subject of thermodynamics to better understand just how heat behaves.

One of the fundamental principles of thermodynamics is the idea of equilibrium. This is the notion that differences in heat will, over time, tend to "even out." When you drop an ice cube into a glass of water, you create a thermodynamic system with a significant heat gradient in it. Heat will flow out of the water and into the ice cube, melting it, and eventually the entire glass will reach a uniform temperature.

One of the interesting conclusions of the idea of thermodynamic equilibrium is that while it's possible for a system in equilibrium to move into a non-equilibrium state, it's so vastly improbable that you can safely assume it'll never happen. There's no physical law that says one spot in your glass of water can't spontaneously get cold and freeze into an ice cube. But it's so incredibly unlikely that you could watch a glass of water for infinite time and never see an ice cube form.

And yet … we exist. We, hugely complicated and structured collections of matter, exist in nature. We're here, when the laws of thermodynamics seem to imply that we shouldn't be here. Our emergence would seem, at first glance, to be even more improbable than an ice cube spontaneously forming in a glass of tap water.

Ludwig Boltzmann was one of the great thermodynamicists. But even he was perplexed by the existence of seemingly thermodynamically impossible things like human beings. He proposed an idea to get around the apparent impossibility of our existence: Maybe we are just ice cubes that formed spontaneously. After all, as we said before, there's no physical law that says ice cubes can't form in glasses of water. It's just really improbable that they should. But in an infinite universe, isn't it possible for the vastly improbable to happen? Since there's nothing preventing it, then it in fact can occur, and the fact that it did isn't itself a violation of the laws of thermodynamics. We're only surprised to find that we exist because, well, we're the ones who are noticing we exist. If "we" were somehow disembodied minds observing the cosmos at a larger scale, the fact that there's a tiny, completely insignificant thermal fluctuation in this one invisibly small spot doesn't seem all that surprising, or even particularly interesting.

There's a problem with that idea, though. If it's possible for us to have emerged in the universe in the way that we did — as complex biological organisms that evolved greater complexity in a steady process taking place over millions of years — then it's also possible for a conscious, thinking being to just emerge spontaneously out of, for instance, a glass of water. Boltzmann advanced the idea that, thermodynamically speaking, in fact it's vastly more probable that a thinking being should emerge spontaneously out of thermodynamic equilibrium than what happened with us. So if we exist, then the universe should, mathematically speaking, be packed wall to wall with these spontaneously emerging "brains."

From Reddit

Very interesting, so how does that tie in to the universe being a colossal quantum computer. There not being other complex creatures like us is proof of that? I’m genuinely curious in this topic

For this to be real (bear in mind it’s still a thought experiment like Shrodinger’s cat) then we are far too ahead in time. It could be that one universe, with infinite computing power, simulated so many and that we are merely saptial-temporal projections.

What i find interesting about the Boltzmann brain is that, statistically and thermodynamically speaking, it must have existed before us as complex organism if we accept that the universe will always move into equilibrium

I’m finna go read some more about this tbh

This video bridges the simulation hypothesis and Boltzmann brains, could be a good start

So just for some clarity. When she says we're all boltzmann brains is that to say we are each individually our own brain, or we are all stemming, living, feeling etc off of one general boltzmann brain?

Me computer... beep boop... boop beep

lol its not the impressive idea you think it is

It really is. It has deep philosophical implications and it kicked off the anthropic principles

Individual Boltzmann brains, which may not look like our brains but some form of matter with consciousness or delusions

if it is the case that our memories and experiences are the fleeting result of some thermodynamic fluctuation, there is no reason to believe they are valid- all of the evidence that underlies science is a fabrication. but if that is the case, then the thermal physics that forms the basis for the boltzmann brain isnt correct either, making the entire notion self-defeating.

if it is instead the case that our memories, which are incredibly uniform and consistent (not in the sense of having a great memory, but in the sense that the universe unfolds according to predictable physical laws), are guaranteed that consistency for some external reason ... then obviously we aren't the result of some purely random thermodynamic process.

and the anthropic principle isnt dependent on the idea of a boltzmann brain, not sure where you got that from.

You miss the point of what I’m trying to say here. It was never about whether such a thought experiment has a truth value. Boltzmann himself says that its conclusion is unreasonable, given that:

p1, p2 are all probabilities of random events x1, x2, such that p1 > p2. That does not mean that x1 (here, Boltzmann brain) will necessarily occur over x2 (the emergence of complex beings (human beings as we know them).

But my point is that Boltzmann showed that there are other possibilities worth investigating. That maybe we are not the apt observers of the physical universe that we think we are. That the universe is not held together by our deterministic understanding of mathematics, but rather through probability and pure chance.

And this is why the anthropic principle is important here. the probability that we exit in a fine-tuned universe which is inhabitable for us is dismally low. It’s like walking into a room full of dice, except that all of them show six. An explanation for this is string theory and the multiverse hypothesis, but it’s precisely this rift between the probabilistic and determinist facets of the universe that seems to render other very improbable anthropic events in the universe possible

you've got it entirely backwards. the repeated failure of theories that try to explain away sentience as a product of random chance suggests that such "other possibilities" are probably wrong.

actually, im hesitant to make a strong claim like that. what I will say is that (and we seem to agree here) the notion of the Boltzmann brain is complete nonsense, and therefore doesn't help either side's case. end of story.

I'm really not a fan of this way of thinking. It reminds me of the "fall through a wall idea". There is something called quantum tunneling where particles have appeared to have moved through walls they should not be able to spontaneously. People have used this to say that an entire person should statistically be able to fall through a wall or floor randomly, if all of the atoms making them up did so. This, in my opinion, is definitely not possible, we just dont yet know enough about quantum mechanics to explain what has happened. Matter behaves differently at different scales, I'm pretty sure that applies to thermodynamics as well. Like they say in that video, the way heat works in a closed system like a room is much different to how heat works throughout the entire universe.

I'm not 100% sure of any of this but I think ideas like this are only entertained by researchers so that they can prove them wrong. They are viewing things like macro scale quantum tunneling and all of our past memories spontaneously appearing in our minds as holes in current theories of reality, as things they need to disprove and find a real solution to.

Yes, it's possible that now is the first moment you've ever perceived but what do you gain from thinking like that, what does that tell you?