Its an interesting idea, but from the posts above it seems the main argument against it is that we are not sampled at random from all humans that ever have or ever will exist, but from the ones that are alive now.
Then how about the related hypothesis that says that most intelligent beings in the universe are confined to their home planets, and do not acheive significant space travel? Any species that do acheive significant space travel would be likely to colonise other planets, and thus have a much greater population than our own. If such species were common at this time, we would expect to be born into one of them. The fact that we am not, makes it likely that such civilisations are rare. This doesn’t say anything about the future, but merely what is likely at present. What are the arguments against this?
It so happens that I’m reading that book now for the second time. “Time”
Ok, to any of you.
I have a box with wooden balls in it. There are either 10 balls in it or 1000, there is no way to know. Your name is on one of the balls. You pull a lever and a ball comes into a slot. You pull the lever until “your Ball” rolls in. It is the third one you pull. Now I ask you, “How many balls are in that box?”
Ten, you answer. why? Because there is a vastly greater likelyhood of pulling 3rd out of ten than out of 1000.
First we have to accept that humanity can not live forever. There is a fixed number of humans who will exist.
Ok, there are 3 futures for humanity.
We continue to multiply, enentually moving out of the solar system to colonize the galaxy. In this case we must be among the very first humans to ever exist.
We don’t leave the planet, but manage to reach the maximum population limit, a kind of equilibrium for 2 billion years, or until the Sun runs out of fuel and swallows us. In this case there is a vast number of humans still to be born and we are still among the first.
Extinction in the near future ( 100 - 2000 years )
We ask ourselves, when am I in time? If a vast number of humans are yet to be born it is most likely that we would be having this debate across planets of a vast interstellar empire.
Given that today 10% of all humans who have ever lived are alive,
which future one is most likely?
Actually, I would answer “It depends. Were the two choices (10 balls or 1000 balls) equally likely to begin with?”
The problem as stated doesn’t provide enough information to allow a statistical answer. Specifically, the problem doesn’t state the probabilities of the two cases before the start of the experiment. If the two cases are equally likely then yes, the probability that the box contains 10 balls given that the third ball has my name on it is higher than the corresponding probability for 1000 balls. But on the other hand, what if the box only contains 10 balls once out of every 10000 runs of the experiment? Then the conditional probability that the box contains 10 balls given that the third ball is the named ball is
You can’t conclude that the box is more likely to contain 10 balls without assuming something about the relative likelihood of the two cases beforehand. Assuming that the two cases are equally likely before the start of the experiment is reasonable for a box full of balls, but when talking about the course of human civilization it’s an unwarranted assumption.
You seem to be ignoring the arguments I’ve already made against exactly this argument, not to mention every other argument against Carter’s hypothesis already made in this thread.
The book is ‘Manifold: Time’ by Stephen Baxter (2000).
The hypothesis seems to imply that the best fit statistically predicts an end to history in two hundred years time;
If this were true;, we would be in a privileged position-
we are at a period in history when statistics are understood well enough to invent things like the Carter Hypothesis,
but not far enough onwards in history to have proved Carter wrong by living through this imaginary terminal point.
Therefore we are in a privileged position in history - and that other famous postulate- Copernican Mediocrity - cannot apply.
Agree. I would add another criticism to the box and balls hypothetical:
Let’s suppose that an experimenter releases three balls from the box and the third ball says “John Smith” on it. The experimenter then brings in John Smith and explains to him the situation – that the box has either 1000 or 10 balls and that John Smith’s was the third name to come out. Smith might very well conclude that it’s more likely that the box has 10 balls.
However, Smith’s conclusion is suspect. Even if the box has 1000 balls, somebody’s name is bound to come out third and that person will get the impression that the box must not have very many balls in it.
Technically, every point in history is privliged. What are the chances that we’d be alive at just the right time so that the world is at this precise state?
Some time ago I read “The End of the World, The Science and Ethics of Human Extinction” (now how’s that for a title!) wherein John Leslie goes into quite some detail about Carters Doomsday-Soon-Theory. Besides the doomsday theory the book also contained this small apparent paradox (The Shooting Room):
One day you find yourself in a room wherein a devil is engaged in a dastardly experiment. On a big sign in the room is this message: “90% of all humans that enter this room will be shot!” Which should be enough to make any man a tad nervous, but a bit later you learn you’ll only get shot if the devil throws two sixes with a pair of dies, and those odds some a whole lot better. But how can the 90% and the 1/36 be reconciled? If people are led into the room in batches, each batch 10 times as big as the previous. If the devil throw two sixes everybody in this batch is shot and the experiment terminated, if not the people from the batch set free and another one ten times the numbers brought in. This way when whenever the devil throw two sixes at least 90% of all people entering the room will have been shot, however any one person still has only 1/36 chance of being shot. Of course the gedanken-experiment suffer from needing a potential infinite number of people – still strange shit if you ask me.