Trolleys and chaos

Suppose that determinism is true and Alice is about to roll a twenty-sided die to determine which of twenty innocent prisoners to murder. There is nothing you can do to stop her. You are in Alice’s field of view. Now, a die roll, even if deterministic, is very sensitive to the initial conditions. A small change in Alice’s throw is apt to affect the outcome. And any behavior of yours is apt to affect Alice’s throw. You frown, and Alice becomes slightly tenser when she throws. You smile, and Alice pauses a little wondering what you’re smiling about, and then she throws differently. You turn around not to watch, and Alice grows annoyed or pleased, and her throw is affected.

So it’s quite reasonable to think that whatever you do has a pretty good chance, indeed close to a 95% chance, of changing which of the prisoners will die. In other words, with about 95% probability, each of your actions is akin to redirecting a trolley heading down a track with one person onto a different track with a different person.

Some people—a minority—think that it is wrong to redirect a trolley heading for five people to a track with only one person. I wonder what they could say should be done in the Alice case. If it’s wrong to redirect a trolley from five people to one person, it seems even more wrong to redirect a trolley from one person to another person. So since any discernible action is likely to effectively be a trolley redirection in the Alice case, it seems you should do nothing. But what does “do nothing” mean? Does it mean: stop all external bodily motion? But stopping all external bodily motion is itself an effortful action (as anybody who played Lotus Focus on the Wii knows). Or does it mean: do what comes naturally? But if one were in the situation described, one would likely become self-conscious and unable to do anything “naturally”.

The Alice case is highly contrived. But if determinism is true, then it is very likely that many ordinary actions affect who lives and who dies. You talk for a little longer to a colleague, and they start to drive home a little later, which has a domino effect on the timing of people’s behaviors in traffic today, which then slightly affects when people go to sleep, how they feel when they wake up, and eventually likely affects who dies and who does not die in a car accident. Furthermore, minor differences in timing affect the timing of human reproducive activity, which is likely to affect which sperm reaches the ovum, which then affects the personalities of people in the next generation, and eventually affects who lives and who dies. Thus, if we live in a deterministic world, we are constantly “randomly” (as far as we are concerned, since we don’t know the effects) redirectly trolleys between paths with unknown numbers of people.

Hence, if we live in a deterministic world, then we are all the time in trolley situations. If we think that trolley redirection is morally wrong, then we will be morally paralyzed all the time. So, in a deterministic world, we better think that it’s OK to redirect trolleys.

Of course, science (as well as the correct theology and philosophy) gives us good reason to think we live in an indeterministic world. But here is an intuition: when we deal with the external world, it shouldn’t make a difference whether we have real randomness or the quasi-randomness that determinism allows. It really shouldn’t matter whether Alice is flipping an indeterministic die or a deterministic but unpredictable one. So our conclusions should apply to our indeterministic world as well.