
In science it often happens that scientists say, 'You know that's a really
good argument; my position is mistaken,' and then they 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, 1987 CSICOP keynote address
