I see what you’re saying, but perspective is not equatable to a math equation. An optimist and a pessimist can both have a complete understanding of the facts, but one predicts that things will get better, and the other predicts that things will get worse, and eventually, given enough time, they’ll both be right.

There is no such thing as a realist. That’s just what someone calls themselves when they don’t realize that their perspective is flawed and unique to themselves.