We discuss two supertasks invented recently by Laraudogoitia [1996, 1997]. Both involve an infinite number of particle collisions within a finite amount of time and both compromise determinism. We point out that the sources of the indeterminism are rather different in the two cases—one involves unbounded particle velocities, the other involves particles with no lower bound to their sizes—and consequently that the implications for determinism are rather different—one form of indeterminism affects Newtonian but not relativistic physics, while the other form is insensitive to the classical vs...

We discuss two supertasks invented recently by Laraudogoitia [1996, 1997]. Both involve an infinite number of particle collisions within a finite amount of time and both compromise determinism. We point out that the sources of the indeterminism are rather different in the two cases—one involves unbounded particle velocities, the other involves particles with no lower bound to their sizes—and consequently that the implications for determinism are rather different—one form of indeterminism affects Newtonian but not relativistic physics, while the other form is insensitive to the classical vs relativistic distinction. We also note some interesting linkages among supertasks, indeterminism and foundations problems in the general theory of relativity.