Frightening Ideas

Discussing with my daughter the flap over Steve Landsburg's recent post, I commented that the people who were angry about it, mostly online, struck me as either stupid or evil. Either they were too stupid to see that he was actually raising an interesting puzzle or they saw that he was doing so but pretended not to, in order to have an excuse to attack someone they disliked or disagreed with.

Her response was that I was wrong, that my mistake was not realizing the degree to which many other people were different from me. To me, ideas are real, important, and sufficiently interesting that my reaction to an argument that appears to prove some frightening or ugly conclusion is to be neither frightened or angry but intrigued. Lots of people don't react that way—and if you see the conclusion of an argument as frightening or ugly, it isn't surprising if you skip over the fact that it raises an interesting puzzle or are too willing to assume that whoever offered the argument must agree with its conclusion.

I am not sure if she is correct or not, but it did start me thinking about other arguments which I find intriguing despite the fact that their implications are disturbing. None of them has the same emotional loading as an argument about rape, but all of them have implications that strike me as more serious, in various directions, than the implications of the argument Landsburg made. Here are three examples:

1. Moral nihilism: 

I have sketched elsewhere my view of the nature of moral philosophy, what Michael Huemer (and, I assume, other professional philosophers) refers to as intuitionism. I read Huemer's book on the subject in part in the hope that he could offer an adequate rebuttal to the best argument against that position that I knew of, since I didn't have one. I still don't, although he thinks he does.

The argument (which I believe was once offered by someone commenting here) is simple. I have moral intuitions—I perceive some acts or outcomes to be good or bad. My preferred explanation is that they really are perceptions of a (non-physical) truth. An alternative explanation is that they are beliefs that got hardwired into my brain by evolution because having those beliefs resulted in increased reproductive success in the environment in which my distant ancestors evolved. That explains the same data, my intuitions, without requiring any additional assumptions, since I already believe in evolution and recognize that some characteristics of how the brain processes information are best explained in that way.

If that argument is correct, not only is there nothing wrong with raping an unconscious victim, there is nothing wrong with doing anything to anyone—right and wrong are merely illusions. I find it impossible to believe that conclusion, but I have no adequate argument against it.

Unless you count this one.

2. We are all brains in vats:

Assume that the growth in wealth and technology that has occurred over the past century continues into the far future. In the world of a thousand years from now, an obvious form of entertainment, the equivalent of movies, books and video games, is simulation—Sim City on steroids—and in that world they will have the wealth and technology to simulate people, and worlds full of people, down to the neuron. A period of history of particular interest, and so particularly likely to be simulated, is the period when mankind made the great technological leaps that made possible the world of a thousand years hence. There will be thousands, millions, perhaps billions of simulations of that period, fully populated with simulated people who believe they are real.

What are the odds that you and I are in the one real version of the present instead of one of the millions of simulated ones?

3. There is no reason to expect the future to resemble the past. At all.

Consider the inductive hypothesis, the claim that the future resembles the past. It is essential to all of science, indeed to virtually all of our attempt to make sense of reality. Without that assumption, the fact that stones fell down when we dropped one yesterday gives us no reason to expect that, if we drop another stone today, it will fall down instead of up. 

Do we have any reason to believe the hypothesis? It is true that it has held, so far as we can tell, through the entire history of the universe. Unfortunately, that argument is circular. In the past, the future resembled the past—each day, stones fell in the same direction. But unless we already know that the future is going to resemble the past, the fact that the inductive hypothesis held in the past is no evidence that it will hold tomorrow.