>>44917952Physical - Material aspects of energy
Special - Spiritual aspects of energy
Dark-type is entirely based on behavior, reflected in our human spirits. It is within our spirit to be evil. Dark-type Pokemon are associated with sin and immoral behavior. Game Freak designed a type based entirely on morality that was originally calculated off of the attacking category based on spiritual energy.
Types were originally classified according to their inherent classification.
Physical types used a Pokemon's physical energy. Special types used a Pokemon's spiritual energy.
You know like Naruto? How chakra is made up of physical energy and spiritual energy. That type of thing. Yin and Yang. In Naruto, Yin is spiritual energy, and Yang is physical energy. In Pokemon, the physical attacking dragon Zekrom is the Black Yin Pokemon from Pokemon White, while the special attacking dragon Reshiram is the White Yang Pokemon from Pokemon Black.
The physical/special split is much more accurate, as it judges a move on its inherent characteristic (whether it is a physical action or a spiritual one), not on the typing it came from.
Bite, Crunch, Beat Up, Feint Attack, Pursuit, and Thief are all physical actions. Biting. Beating someone up. Hitting someone physically through a sneak attack. Stealing from someone.
The Dark-type itself is in the special category, since behavior and morality are based on a human's spirit (mind), not their physical energy (body), but all of these moves were done out of physical action and energy.
And this is my opinion: Fairy would have most likely been in the special category. Not just for the type balance (having 9 physical types and 9 special types), as well as Eevee evolving into special types of Pokemon only so far. But also because Fairies are invisible or not known to us: they exist but we don't know they exist. Some of them are actual spirits, and others are so undetectable that we might as well confuse them for spirits.