I’m currently reading the book Mainfold: Time by Stephen Baxter. Early in the book there’s the discussion of the Carter Catastrophe. What this is, bascially, is a statistical argument that the end of the world (or at least the human portion of it) is coming.
Basically, it argues that there are three possible paths for human population to take - continued exponential expansion, equilibrium reached at a certain population that continues indefinitely, or exponential expansion in the short term followed by a crash to zero in the near future (ie, the catastrophe). The only one in which we have a reasonable probability of showing up in the timeline where we are is the catastrophe option.
By way of example given in the book, suppose you have a box that holds either 10 marbles or 1000 marbles, all of which are black save a single red one. Without knowing how many marbles are in the box, you remove them one at a time. Now, on the third pick, you get the red one. Obviously, you’re much more likely to get the single red one that early if there are only a few marbles to begin with.
Now, there are a bunch of problems with this argument that I can see, not the least of which is that the population of humanity isn’t constrained beforehand like the number of marbles are.
So, I’m leaning towards the “I feel fine” side of the argument. It’s kind of hard not to be drawn in by the “It’s the end of the world” side, though.
I posted a review of this on rec.arts.sf.written about a year ago (I hated the book) and some of the statisticians tore the “Carter Catstrophe” argument to shreds.
It’s just silly on the face of it.
It argues backwards from a conclusion. If you have 52 different cards in a deck, and you pull the Ace of Spades, it’s no big deal…unless you predict that you’re going to pull the Ace of Spades before drawing a card. You have a 100% chance of pulling some card. Your parents (barring miscarriges, etc) had a (for the sake of argument) 100% chance of having some kid. Baxter’s theory that because that kid happened to be you in particular, the world is about to end is frankly reminiscent of the stupid “Intelligent Design” argument that says “Well, we couldn’t have evolved in a universe with different rules so obviously someone built this universe with us in mind, or we wouldn’t be here” :rolleyes:
A synopsis of Baxter’s argument: (pp 46-7 of the British hardcover version):
Cornelius says that human population can grow exponentially, stablilze or crash. “In the first two cases, the vast majority of humans are yet to be born” (italics, his)
Later, Malenfant continues the argument with “Remember [Cornelius’s] game with the balls and the box. Why are we here now? If we were really going to the stars, you would have to believe that you were born in the first one-billionth part of the total human population.”
The thesis concludes with "If there is a near future extinction, it is overwhelmingly likely that we find ourselves alive within a few centuries of the present
day. Simply because that is the period when most humans who ever lived, or ever will live, will have been alive
Baxter is an OK writer (other than his psychotic hatred of NASA and his non-existant grasp of U.S. Politics), but normally his science is pretty on-track. This time, he blew it big. IMHO.
Fenris (who hated the book. Especially the
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Dyno…stop reading here. Seriously!
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blatent swipes from 2001: A Space Odessey and the “Hey, genocide on a scale that would’ve made Hitler blush is jes’ fine!” thing.
Another warning for the weak at heart to avert their eyes (especially if you cannot stomach much of the departed John John’s rhetoric), but there is already a fair amount on information that Baxter’s expansion ideas are not based in reality. As pointed out beginning around pages 3 and 4 of the 6 billion? thread, the U.N. has, currently, three possible population estimates. None of them show exponential growth. In addition, the U.N. continues to have to revise its estimates downward as population rates fall throughout the world.
Continued exponential expansion is false from the get-go since we are not in an exponential expansion mode at this time.
Also you should remember that whole evolution thing. The point of it existing is to make us survive better. Therefore as we go along we have a less chance of being obliterated.
Well, there’s that, but that doesn’t really address the kind of thing it’d take out to wipe out the entire human species, anyway. Evolution can’t fight supernova radiation.
Anyway, like I said, I don’t particularly believe that the world is coming up anytime soon. Apparently, most of the rest of us don’t, either
Well, assuming enough radiation to kill us of as we are now…we’d all be dead before we had a chance to evolve to the point where we could survive it, no?
Supernova radiation would kill fast. Evolution works slowly.
What Baxter calls the “Carter catastrophe” is normally known as the “Doomsday argument” in philosophical circles. Though there are points in the argument that may intuitively appear weak, it appears to be logically sound, and there is no generally accepted refutation of it.
By “logically sound,” I mean that the conclusions of the argument do appear to follow logically from its premises (one can still find reasons to object to the premises).
Here’s the way that I refute the OP. Suppose the humanity becomes extinct tomorrow. That means we are alive at the end of the world. But with our species ending at any particular point, the probability that we would be alive at that point is quite low. Now suppose, for the sake of argument, and that modern humanity has existed for 100,000 years and will continue to exist for 100,000 years. Than we are currently alive at exactly the halfway point, which is also highly improbable. Similar arguments can be made for any specific numeric point. So if humanity does, in fact, become extinct, our particular selves have to be living in a time period that is highly improbable.
I think this argument is logically invalid. EVERY card I draw is statistically unlikely. Any one five card hand is very unlikely. Yet every time you deal the cards, everyone gets a hand.
Or look at it another way. Suppose I’m picking numbers for a lottery. Statistically, it is very unlikely that the winning numbers will be highly ordered…say 01, 02, 03, 04, and 05. But that combination of numbers is exactly as likely as any other combination of numbers, and you are just as likely to win guessing that as you would 33, 27, 86, 10, and 42. Sure, it SEEMS like the second guess is more likely to win, because in our experience highly ordered results are unlikely. But of course, EVERY sequences is exactly as unlikely.
So, you can’t say that since it would be unlikely for us to be at the dawn of the human species, we must be near the end or at the middle. ANY point on the continuum is exactly as unlikely as any other. It would be unlikely for us to be exactly 44.567473% of the way through humanity’s span. But at some point, either in the past or the future, we were/will be. What are the odds that we are exactly at that point now? Very low. Just as low as the odds that we are at 00.00000001%, or 99.9999999%. You can’t extract information from this.
I don’t think the argument is based upon the time period we exist in…it’s based upon the fact that the greatest percentage of the population exists now.
In other words, it’s not that we’re alive in year x out of y that’s important to the argument, it’s the fact that it’s highly unlikely that we’d be around at this point in time if this weren’t the point in time where most humans are going to be around.
Like I said before…I don’t really believe it, but there’s something oddly compelling about it.
