How Determinists Cross the Street

It’s pretty much inevitable that you will walk across a street at some point. How you cross it is determined by a number of factors, including your desire to cross it safely. Although it’s not inevitable that you will cross the street with your eyes open, it’s a good bet, given your desire not to be injured or killed.

What if you come to believe that all your behavior is fully determined: that in any given situation you couldn’t have done other than what you did, given all the factors operating? How might this change, if at all, your approach to crossing the street?

If determinism is true, then the way I cross the street next time is fully a function of various factors coming to bear at that time. If I cross the street with my eyes open, that’s determined; if I cross it with eyes closed, that’s determined too. But might the belief that behavior is determined play a role in determining how one crosses the street?

As a consequence of their belief in determinism, some misguided fatalists might say "The future is fixed: I’m either fated to get across the street safely or not. If I am fated to be hit by a car, then it doesn’t matter what precautions I take. Since the future is fixed, it doesn’t matter what I do." The last statement is pretty obviously a false non-sequitur, but let’s see precisely why.

It is true that whether one gets across the street safely or struck by a car is determined or "fated," as the fatalist says, but of course neither he nor anyone else knows which way it will turn out. It is also true that the way one crosses the street, eyes open or eyes closed, is determined. If one desires to cross safely, then this desire helps determine that one will cross eyes open, not closed. And clearly, the way in which one crosses the street influences the chances of getting across safely. (I omit here any discussion of the role of random influences, since these are by definition uncontrollable and presumably have an equal chance of working for or against one’s safety.)

The upshot is that although whether one gets across the street safely or not is indeed determined, the choice to walk across eyes open, motivated by the desire to get across safely, plays a pivotal role in determining the outcome. The ordinary, widespread desire to live matters greatly in how people cross the street – it figures as one of the primary proximate causes of safe street crossing behavior. This desire combines with the knowledge that cars sometimes intersect with careless pedestrians (with deadly consequences) to generate the eyes-open approach to street crossing. If living another day matters to you, then keeping your eyes open matters too.

This shows that what the fatalist does (keeping his eyes open or shut) indeed matters, even though his street crossing behavior is determined. So he is quite wrong to say "Since the future is fixed, it doesn’t matter what I do." The deterministic unfolding of his behavior is a function of beliefs and desires, and unless his fatalism undercuts the basic desire to live, then his knowledge that his behavior is determined won’t change his policy of crossing with eyes open.

Still, given the small chance that believing in fatalism might undercut the desire to live, it would be best to avoid such a belief. Unlike a belief in determinism, fatalism might in extreme cases be fatal. The best defense against this fate is to think through the problem. As we’ve seen, fatalism (and some less virulent forms of being despondent about determinism) – is determined by the reaching the false conclusion that it doesn’t matter what one does, that one’s fate is determined to be a particular outcome whatever one does. The truth is, however, that one’s fate as a particular outcome is often determined by what one does, even though actions, along with one’s desires and beliefs, are themselves determined. The fact that they are determined doesn’t lessen their essential role in determining one’s fate. The best way to avoid being fatalistic or despondent about determinism is to understand clearly that our actions do matter in bringing about the outcomes we want, even though we don’t "ultimately" choose these actions, or the desires that motivate them, from some uncaused vantage point. (And besides, being uncaused choosers doesn’t help matters, see "The Flaw in Fatalism").

Having read this description of how determinists cross the street, and having been inoculated against any inclination toward fatalism, you are probably asking "But why do determinists cross the street?" On this question, I have no clue…

TWC - 6/01