"Pokémon type weaknesses explained."

So I have been hearing around the internet that some type weakness/strengths are simply inexplicable, so I will be attempting to explain themPsychic<<Dark: The famously weird one. Well, to me Dark types represent a corruption or confusion of the mind. Meanwhile, psychic moves are carried out through mental power and concentration, and if you can't concentrate or think, good luck carrying out a psychic move.Ghost and Normal can't affect each other: In my mind, normal types are the pokemon which most closely resemble humans, which can't interact with ghosts. Therefore, Normal types too, cannot interact with ghosts.Dragon<<Fairy: Usually dragons are engaged in combat (think knights), and they have no way to fight against fairies which use magic.Can anyone explain to me why dark types are weak to fairy types. I have two expiations -- either fairy types double as "light" or fairy types are "pure" and dark types are "corrupted." However the first explanation would make fairy types immune to dark types and the second would make fairy weak to dark.Also how come fairy does 1/2 damage to fire? That is the most random thing I have ever seen in Pokémon (and I seen a lot of weird things).In response to replies: If physic is weak to dark because of fear of the dark, why does it get special immunity? It is less rational than bugs but more so than ghosts. Why aren't ghost or bug types also immune to physicFor the fairy>dark good vs evil theory, doesn't that apply to fighting type? or are both fairies and fighting types "good"As for the psychic>poising, psychic takes 1/2 damage because a physic true essence doesn't lie in the body, it lies in the mind. As long as the body is still alive, the mind can proceed at full power (This also explains the phobias theory because they rely on intimidation more than physical damage)Poison (and fighting) take 2x damage from psychic because these two types rely on brute force and as a result are rather dull, and easily tricked by physic types. Meanwhile psychics take 1/2 damage from each other because they are more cunning and less easily deceived.Let me know what you think via /r/pokemon http://ift.tt/2pK5Jzc