The Earth does not block the light to or from the Moon. If it did it would be an eclipse, there are as many degrees of eclipse as there are phases to the Moon. Now back to astronomy 101, The Moon orbits the Earth. That means it goes around the Earth. As the Moon is orbiting the Earth the Earth is orbiting the Sun. Different perspectives of the Moon from an Earth based viewer are possible. The Moon while part of it is always full from the Sun side only shows phases with respect to Earth. A person may see only a phase of the Moon (i.e. half) that does not mean the Earth is shadowing the other half. It does mean that from a vantage point on Earth we only see half of the Moon lit. From a vantage point outside of the Earth it is still a full Moon. The dark half that you see as an observer is from the shadow of the Moons own making..