Most athletic achievements speak for themselves. Their names are self-evident—no one has to question the foundation of a “no-hitter” or “quadruple double” or “500-yard passing game.” There’s no space left for subjectivity.
And then there’s “perfect game.”
This breaks out from the aforementioned structures. (Just try figuring it out in the context of the other terms: "What does it mean to be perfect?” demands far more than “What does it mean to allow no hits?”) “Perfect” is heavy. Its standards can be technical, aesthetic, moral, philosophical, all of the above. It can be physically impossible. A perfect game does not sound like a statistical standard as much as it sounds like an ideal.