A rarity and its existence was once a myth, as was the existence of a Black Swan or a Black Tulip. Anyone interested may want to follow up on the story of the Black Swan (not the ballet film, the actual swan) and how its discovery posed a number of big philosophical questions which were initially addressed by the great Scottish Philosopher John Stuart Mill and much later via the work of Nassim Nicholas Taleb. Indeed, if you read Taleb, you may start to understand why your religious beliefs are as they are, or why you may feel one way or another about Anthropomorphic Global Warming. Fascinating.