- There are three possible and mutually exclusive explanations for the world and its contents: materialistic naturalism, theism, or teleological naturalism.
- The correct explanation of the world and its contents is not materialistic naturalism.
- The correct explanation of the world and its contents is not theism.
- Therefore, the correct explanation is teleological naturalism.
Now, already a possible terminological confusion looms: isn’t it the case that teleological arguments are inevitably arguments for theism? Well, no, as it turns out. It becomes apparent as the book progresses that what Nagel is arguing for is an Aristotelian type of natural teleology: an immanent, this-worldly type of tendency or bias on the part of nature to produce certain ends. Such teleology does not posit any transcendent Mind in which intentions or goals reside.
The argument seems valid, and perhaps the first premise is relatively inoffensive to naturalist and theist alike. Argument will thus center on premises 2 and 3.