Alien attack, nuclear war.

Rarely does philosophy produce empirical predictions. The Doomsday argument is an important exception. From seemingly trivial premises it seeks to show that the risk that humankind will go extinct soon has been systematically underestimated. Nearly everybody's first reaction is that there must be something wrong with such an argument. Yet despite being subjected to intense scrutiny by a growing number of philosophers, no simple flaw in the argument has been identified. It started some fifteen years ago when astrophysicist Brandon Carter discovered a previously unnoticed consequence of a version of the weak anthropic principle. Carter didn't publish his finding, but the idea was taken up by philosopher John Leslie who has been a prolific author on the subject, culminating in his monograph The End of the World (Routledge, 1996). Versions of the Doomsday argument have also been independently discovered by other authors. In recent years, there have been numerous papers trying to refute the argument, and an approximately equal number of papers refuting these refutations. Imagine a universe that consists of one hundred cubicles. In each cubicle, there is one person. Ninety of the cubicles are painted blue on the outside and the other ten are painted red. Each person is asked to guess whether she is in a blue or a red cubicle. (And everybody knows all this.) Now, suppose you find yourself in one of these cubicles. What color should you think it has? Since 90% of all people are in blue cubicles, and since you don’t have any other relevant information, it seems you should think that with 90% probability you are in a blue cubicle. Let’s call this idea, that you should reason as if you were a random sample from the set of all observers, the self-sampling assumption. Suppose everyone accepts the self-sampling assumption and everyone has to bet on whether they are in a blue or red cubicle. Then 90% of all persons will win their bets and 10% will lose. Suppose, on the other hand, that the self-sampling assumption is rejected and people think that one is no more likely to be in a blue cubicle; so they bet by flipping a coin. Then, on average, 50% of the people will win and 50% will lose. – The rational thing to do seems to be to accept the self-sampling assumption, at least in this case. Now we modify the thought experiment a bit. We still have the hundred cubicles but this time they are not painted blue or red. Instead they are numbered from 1 to 100. The numbers are painted on the outside. Then a fair coin is tossed (by God perhaps). If the coin falls heads, one person is created in each cubicle. If the coin falls tails, then persons are only created in cubicles 1 through 10. You find yourself in one of the cubicles and are asked to guess whether there are ten or one hundred people? Since the number was determined by the flip of a fair coin, and since you haven’t seen how the coin fell and you don’t have any other relevant information, it seems you should believe with 50% probability that it fell heads (and thus that there are a hundred people). Moreover, you can use the self-sampling assumption to assess the conditional probability of a number between 1 and 10 being painted on your cubicle given how the coin fell. For example, conditional on heads, the probability that the number on your cubicle is between 1 and 10 is 1/10, since one out of ten people will then find themselves there. Conditional on tails, the probability that you are in number 1 through 10 is one; for you then know that everybody is in one of those cubicles. Suppose that you open the door and discover that you are in cubicle number 7. Again you are asked, how did the coin fall? But now the probability is greater than 50% that it fell tails. For what you are observing is given a higher probability on that hypothesis than on the hypothesis that it fell heads. The precise new probability of tails can be calculated using Bayes’ theorem. It is approximately 91%. So after finding that you are in cubicle number 7, you should think that with 91% probability there are only ten people. That is the Doomsday argument in a nutshell. After hearing about it, many people think they know what is wrong with it. But these objections tend to be mutually incompatible, and often they hinge on some simple misunderstanding. Be sure to read the literature before feeling too confident that you have a refutation. If the Doomsday argument is correct, what precisely does it show? It doesn’t show that there is no point trying to reduce threats to human survival "because we’re doomed anyway". On the contrary, the Doomsday argument could make such efforts seem even more urgent. Working to reduce the risk that nanotechnology will be abused to destroy intelligent life, for example, would decrease the prior probability of Doom Soon, and this would reduce its posterior probability after taking the Doomsday argument into account; humankind’s life expectancy would go up.

No telling when, but in geological time it is bound to happen. It will happen faster if we don't eliminate nuclear weapons. It would probably help if there were no religions too.

If it take the Biblical approach...who knows according to the Bible we won't know when Jesus comes back. If you go with the next doomsday theory it will be 12/21/12 because the Mayan calendar ends then and apparently it has predicted other major events. The LHC which as you can tell by my name is scary, could possibly destroy us in a number of ways ranging from black holes growing beyond microscopic proportions and sucking in the earth, to the LHC producing a phenomonom known as strange matter which when it comes in contact with other things turns that stuff into strange matter and everything just goes to shit, or it may rip open the fabric of space and time and do what ever the hell that will do. On the other hand it may just explain a bunch of stuff that we didn't know before. Robots could become aware and kill us, specifically nanobots which are programmed to self replicate(eventually, they can however keep their host moving after it has died. They found that out when a virus that had the first nanobot attached continued to move after the virus died). There are various Genetic experiments going on right now for god knows what reasons, I believe germans have successfully mixed certain human genes with a breed of cows, some other people combined spider genes with a breed of goats and hope to breed the goats so as to harvest a usable form of spider silk. There are many types of biological weapons under production, the ever present threat of how much we are fucking up our planet and yet we don't seem to care, so we may suffer the next Ice Age as explained in Day After Tomorrow if that movie had any scientific backing, hell if I know. The one thing I am sure of is the world is a scary ass place and almost every one of those may involve zombies. The bible metions the dead rising from their grave, the biological and genetic experiments and the LHC can possibly bring forth the crowds crying for brains. The global thing maybe not unless the planet gets so pissed that it says fuck it and unleashes zombies by infecting people with some airborne virus just so it can wipe the scourge that is humanity off its face so it can live happily. Oh and I almost forgot the fact we may just blow the shit out of ourselves with the damned nuclear arms that almost every country, less Japan because they have seen the bad side of giant bombs that can level entire cities with no fucking aiming needed, when we all get pissed and set them off we can enjoy our wasteland and that's when earth will unleash it's Geo-Zombies...WE ARE SCREWED!!!!! Have a nice day. :)

Whenever those liberals in favor of population control get in to congress and whitehouse.