After omnizoid asked whether people want to debate him on Functional Decision Theory (FDT), he and I chatted briefly and agreed to have a (short) debate. We agreed the first post should be by me: a reaction to omnizoid's original post, where he explains why he believes FDT is "crazy". In this post, I'll assume the reader has a basic understanding of FDT. If not, I suggest reading the paper. Let's just dive right in the arguments omnizoid makes against FDT. Here's the first one: > One example is a blackmail case. Suppose that a blackmailer will, every year, blackmail one person. There’s a 1 in a googol chance that he’ll blackmail someone who wouldn’t give in to the blackmail and a googol-1/googol chance that he’ll blackmail someone who would give in to the blackmail. He has blackmailed you. He threatens that if you don’t give him a dollar, he will share all of your most embarrassing secrets to everyone in the world. Should you give in? > > FDT would say no. After all, agents who won’t give in are almost guaranteed to never be blackmailed. But this is totally crazy. You should give up one dollar to prevent all of your worst secrets from being spread to the world. So if I understand this correctly, this problem works as follows: 1. The blackmailer predicts - with accuracy googol-1/googol - whether you will pay $1 if blackmailed. He does so by running your decision procedure and observe what it outputs. 1. If yes, he blackmails you. If you don't pay $1, your worst secrets are spread. This would cost you the equivalent of, say, $1,000,000. 2. If no, he doesn't blackmail you. 2. The blackmailer blackmails you. (To be clear, this is my interpretation of the problem. omnizoid just says there's a 1/googol chance the blackmailer blackmails someone who wouldn't give in to the problem, and doesn't specify that in that case, the blackmailer was wrong in his prediction that the victim would pay. Maybe the blackmailer just blackmails everyone, and 1 in a googol peo