Abstract

I argue that anything a baseball causes—if baseballs exist—is also caused by the baseball's atoms working in concert. Moreover, a baseball is ‘causally irrelevant’ to what its atoms cause. These two claims imply that baseballs, if they existed, would be at best mere overdeterminers of whatever they cause. From this we can draw two conclusions. First, our perceptual reasons for believing in baseballs are no good and whether baseballs exist, just like whether arbitrary sums exist, can be decided only by philosophical argument.Second, there aren’t any baseballs. For, we should resist causal overdetermination and assume, unless forced to do otherwise, that effects are not systematically causally overdetermined. Baseballs would systematically causally overdetermine the effects of their constituent atoms. And so, the bias against systematic causal overdetermination gives a positive reason—in addition to those of Ch. 2—to deny that baseballs exist.