Gandalf’s view is that of Tolkien’s own Christian moral perspective, following the teaching of St. Augustine, that evil has no substantial existence in itself (because God does not create evil things) but is merely the absence of the light of goodness. It is for this reason that Sauron is the Dark Lord and for this reason that the Dark Lord’s domain, Mordor, means “Black Land” or “Land of Shadow” in Elvish.
