'Come on - You mean Ahab thought Moby was the only great white whale?'
This is funny. The biggest reason is that deep in the back of your mind as you are reading this tale, what if Moby did not have that distinct coloring? I mean, if I have a pit bull take my hand off, I am not going to be able to distinguish one bloody pit bull from another.
However, I know there is supposed to be more in the symbolism of the whiteness. Below is an easy excerpt from the Sparknotes on the subject:
Whiteness, to Ishmael, is horrible because it represents the unnatural and threatening: albinos, creatures that live in extreme and inhospitable environments, waves breaking against rocks. These examples reverse the traditional association of whiteness with purity. Whiteness conveys both a lack of meaning and an unreadable excess of meaning that confounds individuals. Moby Dick is the pinnacle of whiteness, and Melville’s characters cannot objectively understand the White Whale. Ahab, for instance, believes that Moby Dick represents evil, while Ishmael fails in his attempts to determine scientifically the whale’s fundamental nature.
All the more reason to wonder what if there was more than one white whale. The symbolism of being white then begs the question--is that the only thing white in this world? Is that the only piece of evil? Of good?
This implies that the clash between good and evil will continue, at any rate. If you get one obsessed man chasing the object down, there may be another. And if the white whale is as symbolic as all the critics supposedly say, they will always be chasing him, like men chasing after gold.