Feynman assumes that particles at microscopic scale travel from A to B by taking every possible path - simultaneously. This accounts for the inference patterns observed in the double slit experiment.
The laws of nature seem mysteriously crafted to allow for complex life. Scientific explanations involve the existence of multiple universes with different sets of laws. Thus, a universe with our set of laws is no more special than the unique configuration of our solar system or the very planet we live on.