Reflections on anthropic principle
There are two axes along which the anthropic principle can be applied: time and universes.
The first one- time- is simple: let’s suppose, there is 3 epochs: before humanity, before the 22nd century and after the 22nd century. Before 22nd century, 10^11 humans had lived. After we will colonize universe so there will be 10^28 humans (according to my own rough estimate). So what’s the probability of being born in a particular epoch, assuming you are born as a human?
It’s clear out that you could not have been born before epoch of humanity, and the probability that you have been born before 22nd century is extremely low.
Nick Bostrom ends his reflexions here and say: “humanity will extinct in the 21st century, because, otherwise, probability that you and me will born after and the 22nd century ≈1 but we have not”.
But there’s an other axe: universes.
Imagine, that you are trying to determine whether you are in universe A or universe B. At the start, your probabilities are 1 to 1. Than you discover that there’s 100 times more humans in universe A than in B. After doing bayesian update, now your probabilities are 100 to 1.
Let’s suppose there are two possible universes: one in which humanity goes extinct in the 21st century, and one in which humanity colonizes the universe. Considering, that >99.99999% of all peoples life in the universe where humanity won and after 22nd century, the only conclusion can be made: humanity have won and now we are in the simulation of 21st century, because there is much more.
… but if this argument is truth, why not push it to its limits? What if there is a universe where there is no the law of conservation of energy and there is infinity space, so there is an infinite number of intelligent beings (and some of them enjoy simulations)?
Infinity is infinitively greater than 10^28, so the probability that our simulation was launched in the universe with infinite energy is 1-1/∞, so ≈1
At this point, you might think: but what if there is just no universe with infinite energy?
Do you remember example with universes A and B?
The fact that universe A might not exist change nothing- you exist, so, there’s 100 to 1 that universe A exist.
Cogito, ergo we are in a simulation launched in a universe with infinite energy and space- where there are so many intelligent beings that, if you tried to write down their number in decimal system of measurement, the stars would burn out before you finishes writing even 1⁄100 digits of this number.
...Or we could realize that we’ve been using an inappropriate mathematical model and then everything adds up back to normality.
I disagree with argument of your article in this context.
I didn’t wrote it explicitly, but if peoples of future spend 0.01% of their time in simulation of the Earth of 21st century, most of peoples, who think they are living in 21st century are wrong.
It’s like you have 2 bag of numbered pieces of paper, in the first one there are 1 million of them, and 1% of them have number 6. An other bag have 10 pieces of paper and they are numbered correctly. Each piece of paper have equal chance to be taken. You take one, and you see 6. From which bag did you take the paper?
Granted.
Therefore, if you were a randomly sampled person from all people who has ever thought or will be thinking that they live in 21st century you should think that there is only a small chance that you indeed live in 21st century.
But, as you are not, in fact, a randomly sampled person, this whole reasoning is unsound.
Likewise here without the “Each piece of paper have equal chance to be taken” condition your reasoning doesn’t work. It’s a crucial assumption, and you are not justified to make it in anthropic scenario.
Why I am not a randomly sampled person?
≈all peoples who believe they live in 21st century actually don’t. I believe that I live in 21nd century, so I don’t live in the 21st century. It sounds like perfect logic.
In be honest, I don’t understand your counterargument right now.
I have simply forgot to mention this condition, but I did mean it.
Okay, let’s start from the beginning. What does it mean to be randomly sampled? How do we know that some things are randomly sampled from some set of things and why this set of things in particular?
Suppose you have a bag of stones. When you blindly pick a stone from this bag why are we justified to assume that it’s a random sample from all the stones from this particular bag at this particular moment and not from some completely different bag? Or from this bag but from two months in the future when it may be filled with different stones instead? Or a random sample from all the stones that exists in the universe? Or even multiverse?
There is some kind of rational principle here, that allows to systematically make maps representing the territory, whether we are talking about stones or people.
Maybe you have to consider all the info you have, so you can’t use all the stones in the multiverse as a reference class if you already know what’s in the bag?
And the stones in this bag strongly influence the chance of picking one, unlike stones in a different bag.
Consider the information you have:
There are stones in this particular bag
There are stones in many other bags
There may be other stones in this bag in the future
There are stones in your neighbourhood within R meters
There are stones in your country
There are stones on your continen
There are stones on the planet Earth
…
There are stones all around the multiverse throughout time and space
And yet from all this information about stones—mind you, we haven’t even begun talking about all information you have—what is relevant to the problem of blindly picking a stone from a particular bag is specifically the information about composition of stones inside it at the moment of picking and not anywhere and anywhen else in space and time.
But how do we know what is relevant? What is the principle that determines it? And is this principle solely about your knowledge state—in the map - or does it have something to do with the territory that your map is trying to approximate?
Good, I think you are looking in the right direction. Now let’s taboo the words “influence” and “chance”. Try to formulate the same idea in terms of physical laws of the universe and processes that go accoding to these laws.
There is no such thing as The One Truly Perfect Class. All of these are rough estimations; some are better than others. It’s better to use “all stones in the multiverse” than to use nothing, but if you have a choice between all stones in the multiverse and all stones on Earth, use the latter as the reference class.
Probabilities are in the mind, and you use a reference class because you can’t calculate the trajectories of stones in the bag — and you have good reasons to believe there is an equal probability for each stone to be chosen (since they’re all in the bag).
It was a fun exercise, thanks.
(I’m repeating it just to make sure you’ve understood my argument. If you have, ignore the next paragraph.)
However, I still don’t understand how this proves that we are not in a simulation: all I know is that my memory claims I live in the 21st century, but I think most people who believe they live in the 21st century are wrong. I can’t see any priors that distinguish between the two universes, so I just use a priori probabilities.