345 | Adam Elga on Being Rational in a Very Large Universe

Behaving rationally involves facing up to conditions of uncertainty; we never navigate the world with perfect confidence. Sometimes we are uncertain about the way the world is, but we can also be uncertain about our place within the world. This kind of situation arises in cosmology (where the relevant world can extend very far in space or time), and also in quantum mechanics (where new worlds might be created at any measurement), but also when we are simply unsure about the future history of...