The total number of stars in the Universe is larger than all the grains of sand on all the beaches of the planet Earth.
Carl SaganWhen permitted to listen to alternative opinions and engage in substantive debate, people have been known to change their minds. It can happen.
Carl SaganIn science it often happens that scientists say, 'You know that's a really good argument; my position is mistaken,' and then they would actually change their minds and you never hear that old view from them again. They really do it. It doesn't happen as often as it should, because scientists are human and change is sometimes painful. But it happens every day. I cannot recall the last time something like that happened in politics or religion.
Carl Sagan