>> “One of the underlying premises of the game,” he said, “is that there’s supposed to be a very simple set of rules and all the cards are exceptions. Every card allows you to break the rules at some point. That’s how I think of it.”
That's Garfield of course and it's his game, but I think it's more accurate to describe the game as an abstract machine and the text on the cards (the "ability text") as its inputs that change the machine's state. Seen another way, the ability text language is the scripting language of the game's rules engine.
The language itself is fascinating. Formally, it's a Controlled Natural Language, but I doubt there is any other CNL that has been in constant use by so many people, while undergoing so many changes to its syntax and vocabulary.
Consider for instance the ability text of the card, Stasis, discussed in the article:
Players do not get an untap step.
Pay {U} during upkeep or Stasis
is destroyed.
That was what was printed on the card in its original, Limited Edition Alpha printing. The same text is now listed as follows on The Gatherer, Wizards' of the Coast M:tG online card database:
Players skip their untap steps.
At the beginning of your upkeep
sacrifice Stasis unless you pay
{U}.
Note how the original card uses "destroyed" while the new text uses "sacrificed" to describe what happens if "you" (the player "controling" Stasis) does not pay {U} (one blue mana) during your upkeep step. In short, "destroy" and "sacrifice" now have different meanings. In particular, while both abilities ultimately move a permanent from its controller's Battlefield to its owner's Graveyard zone, "sacrificing" a permanent doesn't "destroy" it, so effects that replace destruction (like regeneration) cannot prevent a permanent from being moved to its owner's graveyard. Neither can "Indestructible", an ability that precludes destruction, prevent sacrifice.
So the ability text language started very loose and informal, a language aimed to help players understand how a card is meant to be played, but over time it has morphed into something else entirely, a precise formal language that leaves no room for ambiguity, given of course a good knowledge of the rules.