Rick Stroud, Author, "The Book of the Moon" states "The reason the moon has phases is that the earth blocks the light of the sun as the moon moves around the earth, so it incrementally gets a little bit more of the suns rays". If this guy should know that the only time the earth blocks the light of the sun is during a lunar eclipse. The sun lights half of the moon all the time and the phases of the moon are the result of the shape of the illuminated portion of the moon as observed from earth.