Since a bunch of people are going ape shit (committing a common statistical fallacy) over Paul Krugman saying that there is a 50% chance of going into a global recession, I figured I would clear it up. The fallacy is as follows: There are two options, either we do go into a recession or, we do not go into a recession. Ok, now without knowing any details at all you could bet 50/50. But, this is not the case. We do know details, and many of them.
The 50% chance comment by Krugman was not a blind shot, he has evaluated the evidence for it and thus, made a calculated prediction. In order to better explain this, I will give the following example: lets say we are predicting the chance that an organism exists, say, a 16ft tall ant that is invisible and can withstand fire for up to 30 hours. Now, if you commit the fallacy I talk about above, you would say there is a 50/50 chance of this organism existing. But, obviously, there is not a 50/50 chance. The chance would be somewhere on the lines of 0.00000000001/99.99999999 (I know, the chance is less than this but you get the idea.) This is also important for people who claim that there is a 50/50 chance of God existing. This is again not the case and the chance is more on the lines of the giant ant I described above as we have no evidence for the existence of a God and a great amount of evidence against.