 How does Kant demonstrate this? Both the thesis and antithesis arguments are apagogic, i.e., that they constitute indirect proofs. An indirect proof establishes its conclusion by showing the impossibility of its opposite. Thus, for example, we may want to know, as in the first antinomy, whether the world is finite or infinite. We can seek to show that it is finite by demonstrating the impossibility of its infinitude. Alternatively, we may demonstrate the infinitude of the world by showing that it is impossible that it is finite. This is exactly what the thesis and antithesis arguments purport to do, respectively. The same strategy is deployed in the second antinomy, where the proponent of the thesis position argues for the necessity of some ultimately simple substance by showing the impossibility of infinite divisibility of substance, etc.