You’re sitting at your couch watching Netflix, when suddenly, the doorbell rings. You open the door and find there’s nobody there; however, there is a mysterious box on your porch. You take it inside and open it. To your surprise, there’s a big red button inside with the label “Kill all psychopaths”. You take some time to contemplate whether to press the button. One the one hand, you believe the World would be a better place without psychopaths. On the other hand, you’re pretty sure only a psychopath would press the button, and you really don’t want to die – even if it means living in a World with psychopaths. What should you do?
Before we proceed, let’s assume the following: you believe the button does what it says, you believe killing all psychopaths is a generally a good thing, but you do prefer living in a World with psychopaths to being dead. Furthermore, you believe only a psychopath would press the button. Given all this, should you press the button?
It seems to me there are two ways to analyze this situation.
Pressing the button makes you a psychopath
One way to look at this problem is to say that it’s one’s actions that determine whether one is a psychopath in the first place. If you go around pressing buttons that kill huge amounts of people, you are a psychopath. If we follow this line of reasoning, it’s clear you shouldn’t press the button: pressing it makes you a psychopath, so the button kills you as well.
Whether you are a psychopath or not is already determined
We could also argue that whether you are a psychopath or not is simply a feature of your brain (present or absent from birth, perhaps), and your actions don’t have an effect on this. Things get a little more complicated now: unlike in the previous analysis, your action now doesn’t causally influence whether you are a psychopath, and by extension whether you will die. You either are a psychopath, or you aren’t. Let’s assume you don’t know whether you are a psychopath. Then if you are a psychopath, pressing the button is a bad idea, and if you aren’t, it’s a good idea. You may be tempted to do assign a probability to you being a psychopath, and then do an expected utility calculation. But here’s the kicker: there’s no way for you to even press the button if you aren’t a psychopath. That’s specified in the problem statement: only a psychopath would press the button. You can therefore be sure that if you’re able to press the button, you are already a psychopath and you will die as a result of pushing the button. So, again, it seems you shouldn’t press the button.
There’s something curious about this line of reasoning though: if you don’t press the button, you can’t be sure whether you are a psychopath or not. Let’s say you believe there’s a 70% chance you aren’t a psychopath. Then, in a way, there is a 70% chance you should have pushed the button – killing all psychopaths but not yourself – even though you couldn’t! In fact, you can be virtually certain you aren’t a psychopath, you still shouldn’t press the button, for if you do, then you were a psychopath all along. Even if you are completely sure you are not a psychopath, you still won’t press the button, for then, you can’t. The probability of being a psychopath is simply irrelevant!
