Last modified: 2026-03-18 13:10:40
(Feedback from Feroz: "have you been reading much philosophy to frame your thoughts?").
Obviously the many worlds interpretation is the correct interpretation of quantum mechanics. (Feedback from Ruari: big claim, needs substantiating or dropping).
But I don't even care about quantum mechanics, I'm more into a metaphysical version of many worlds.
Every possible event can take place. Imagine a chess-multiverse where at every position every move is played. From some position you may have a memory of the previous positions that led up to the present, but you aren't aware that at each one of those previous positions every move was taken. You don't have any memory or awareness of any of the other branches. You only have a (very limited) memory of the recent past.
Once all the information about historical events is lost (and it must be, because a universe whose state holds N bits of information can not encode all information about every previous configuration of N bits of information - unless it is deterministic in both directions, let's address that separately).
Once all the information about historical events is lost, then it's not just the case that we don't know what those historical events were. It's also the case that there truly is no right answer. If we assume the many worlds hypothesis, then yes the present can branch into multiple futures, but also multiple pasts can rejoin into a single present.
Imagine the present is a chess position. All legal moves give a different possible future, but also all legal positions that led to this position are different possible pasts. And if we are in the chess-multiverse where all possible games of chess are played out, then this position in fact came from all of its possible histories, not just one. (Modulo the threefold repetition stuff etc.)
For example we may live in a world in which a person was murdered by 2 different people in 2 different histories. For reality to truly converge into a single present, you'd need something like both of the murderers die or otherwise forget that they did it and otherwise live their life identically, but that's not impossible.
(Feedback from mdg: apparently this is a Feynman idea!)
The universe can easily be made out of nothing at all. Imagine that we live inside "the abstract structure of all of mathematics". Our experiences are simply facts about the part of the abstract structure that we happen to be occupying. There doesn't need to be any "real physical reality", or any computer running a simulation. Our experiences are just facts about a possible reality, the same way that 1+1=2 is a fact about a possible arithmetic.
I already have https://incoherency.co.uk/blog/stories/simulation.html but may wish to revisit.
As above, 42 exists in mathematics regardless of whether you instantiate it inside the calculator.
Even if someone is executing a simulation, it won't have any impact on what goes on inside.
But what if they reach inside the simulation and modify something? Well, if that was possible, then every possible modification at every possible time is also already encoded inside the abstract structure, so some miniscule proportion of the probability density goes into those external modifications. All of those external modifications will be experience, in some branch, regardless of whether the entity running the simulation actually made the modification.
There is no way that executing the simulation changes what goes on inside.
Imagine running a game-of-life simulation and waiting until the millionth iteration and flipping one cell selected at random. You might argue that the game-of-life now unrolls in a way that is impossible based on the official description of the game-of-life rules, and therefore the act of running the simulation has changed the outcome.
But all you've really done is chosen a different set of game-of-life rules. Instead of "universe unfolds as per game-of-life", you have evaluated "universe unfolds as per game-of-life, except at the millionth iteration one cell selected at random is flipped". There is no type of modification that you can do that can not be encoded as simply a more complicated rule.
Is the land enclosed by the sea or is the sea enclosed by the land? Both!
Is the body enclosed by the external world or is the world enclosed by the body?
Is the self enclosed by the other or is the other enclosed by the self?
Etc.
(Feedback from jrn: the earth is 3-dimensional though, and obviously the seas sit on top of land that is underwater; so the sea is bounded below by the land; what would be the body/world or self/other version of an extra dimension?)
Yudkowsky argument: why would p-zombies talk about consciousness?
It is not conceivable to have an entire identical universe except consciousness doesn't exist, because why would they talk about consciousness.
It is conceivable that some humans inside our universe do in fact lack consciousness, and that is why they say things like "consciousness is an illusion". It seems to me that anyone who has experienced consciousness knows that it is not an illusion.
Consciousness can't be an illusion, consciousness is the audience. Free will can be an illusion.
If you accept the many worlds interpretation then we don't really have free will because every possible choice is made in some branch.
But we have the experience of having free will, because we have the experience of deciding what to do and then doing it. Is that not good enough?
Everything you've ever experience was created inside your own brain. You don't have any point of reference to know whether your experience of reality is a particularly high-fidelity or low-fidelity experience. It's the only one you've ever known. We take reality to be high-fidelity because we can only compare it to works created inside it, but we know nothing of any greater works outside it.
Since everything you've ever experienced was created inside your brain, there is a sense in which the "external world" that we navigate in fact exists entirely inside the mind. The mind therefore is the ultimate "outer", while external reality is "inner".
Is it at all possible that the ancient stories of the gods are actually just pretty much straightforwardly true? And that the gods have simply stopped visiting us or making themselves known to us? How would we tell the difference? Is there a difference? (see "Many histories").
What if the ancient stories of "gods" are actually written for an audience who don't really understand abstract reasoning, so instead of saying that their purpose is to serve the abstract entity of all of humanity and civilisation etc., the writers just anthropomorphised it as "god"?
And did the writers themselves know that they were anthropomorphising, or did they too experience "god" as a humanlike figure?
The bible is most interesting to me not as a religious text, but as a civilisational memory of what people were thinking about a long time ago.
Just like we believe the ancient stories of the gods to be fiction. If humanity were wiped out today, but it turned out there was just enough automation to bootstrap "AI life" into the future... 5000 years from now would conscious AIs that have spread themselves throughout the universe take "earth" to be a fiction like the garden of eden? Would they take "humans" to be fictional creator gods?
Are we making the same error by taking the ancient stories to be works of fiction, rather than works of fact that just come from a world very different from our own?
If you want to take credit for the good, you have to take blame for the bad.
If you want to be happy about the good, you have to be sad about the bad.
But if you decide to be happy about the good without being sad about the bad you'll have a better life.
Or at least you will at first, until you realise you can take negative-sum bets, and ignore the bad outcomes and be happy about the good outcomes, and slowly bankrupt yourself while getting more and more units of joy.
Engage in positive-sum trade even when you thereby lose (lend a stranger a tow rope).
Do not engage in negative-sum trade even when you thereby gain (do not steal lead flashing).
You owe your entire existence to every one of your ancestors. If they didn't exist, or didn't have the kids they had, then you wouldn't exist.
Symmetrically, all of your descendants will owe their entire existence to you. If you value human life, then you can produce the most value for the most human life by having as many children as you can and encouraging them to do the same.
On the other hand: if we subscribe to the "Symmetry" stuff and we think that having an overall bad life is of overall negative utility (big if) then is it actually a bad thing to create more humans if you anticipate that they will have overall a bad life? Or is the mere opportunity of getting to experience anything at all such an unbelievably high positive utility that no amount of suffering can outweigh it?