Water ---> Fire: Water eliminates fires
Water ---> Ground: Water causes erosion of the soil forcibily moving it
Water ---> Rock: Similar to Ground, it breaks up rocks
Water -/-> Dragon: Dragons supposedly have thick hides, and using backwards logic their fire breath can protect themselves from water
Water -/-> Grass: Grass and Plants can absorb water
Water -/-> Water: Water can't destroy water. lol
Steel ---> Ice: A bizzare one, but steel isn't phased by ice and can destroy most forms of ice with little problem
Steel ---> Rock: Probably refers to how in earthquakes steel buidlings hold up better than buildings made of cement, rock, stone, etc.
Steel -/-> Electric: Steel conducts electricity, although it's beyond me why Steel wouldn't be totally immune to Electric rather than it being a neutral
Steel -/-> Fire: Hitting a fire with a steel weapon doesn't do much. lol
Steel -/-> Water: Water can flow around steel, but stainless steel doesn't rust so water isn't overly effective against it which is why it's neutral against steel.
Rock ---> Bug: *squishes bug with a rock* It's super effective! The bug did more than faint!
Rock ---> Fire: Rocks don't really burn unless in extreme conditions.
Rock ---> Flying: Most likely referring to "Kill two birds with one stone" or just to the general logic that most flying animals can get fatally injured relatively easy do to their dependence on their wings
Rock -/-> Fighting: I think the creators watched to many martial arts movies were people chopped rocks in half. lol
Rock -/-> Ground: Not much to say here that isn't a given, ground absorbs blows easily from falling rocks
Rock -/-> Steel: See about Steel, since Rock types logicaly should be neutral against Steel. imo
Psychic
Dark: The strongest mentally can become overcome by the forces of evil for their stubborness? lol either that or maybe a Star Wars reference on how Anakin couldn't master psychic powers until he became part of the dark side.
Psychic ---> Fighting: Fighters can become predictable and tend to use the same, strongest aproach, rather than being strategic as psychics do.
Psychic ---> Poison: Psychics apparently know about medication and can find an antivenin for each poison.
Psychic -/-> Psychic: Countering with similar logic to lessen damage
Psychic -/-> Steel: Psychics use the essence of nature and steel isn't natural.
Poison ---> Grass: Similar to animals and people, plants are susceptible to poison.
Poison -/-> Ground: You can't poison ground persay, but you can poison the microbes and organisms in the soil, which is probably why this isn't a full immunity,
Poison -/-> Ghost: How the heck would you poison a ghost anyway? Should be an immunity. imo
Poison -/-> Poison: Poison is ineffective on poison, common sense.
Poison
Steel: Try to poison an inanimate object, go ahead.
Normal -/-> Rock: It's hard for a person or animal to break rocks without tools unless they're a Blue Whale being thrown out of an aircraft.
Normal -/-> Steel: Steel is difficult to break, especially with bare claws.
Normal
Ghost: Ghosts aren't physical and thus can only be hit with elements.
Ice ---> Dragon: Dragons are cold-blooded and can not survive in the cold.
Ice ---> Flying: Migrations of birds away from the cold and the frost that can kill insects
Ice ---> Grass: Frost kills plants
Ice ---> Ground: Ice causes the ground to solidify and be less mobile, also causes stress to the particles. Glaciers can carve ground away also. IMO This should have been a Ice ---> Rock instead since rocks can be stressed into breaking by the cold and can be pounded by icce flows.
Ice -/-> Fire: Ice can kind of lower the power of fire, but it isn't very effective since most of the ice disappates.
Ice -/-> Ice: Ice can't do too much damage to itself.
Ice -/-> Steel: Steel doesn't get stressed easily by the cold.
Ground ---> Electric: Electricity can be dissipated into the ground very easily, and can force the loss of conductivity.
Ground ---> Fire: You can use sand/dirt/etc. to put out a fire.
Ground ---> Poison: Ground clay can be used to remove SOME poisons from the body, and soil can dampen the potency of poison.
Ground ---> Rock: Erosion again, landslides can take out rocks.
Ground ---> Steel: Steel usually depends on good ground to stand, landslides can take out steel structures.
Ground -/-> Bug: Bugs can burrow into the ground.
Ground
Flying: Apparently flying pokemon never land in battle, so they can't get hit by it.
Ground -/-> Grass: Plants use ground/soil as a foundation and trap it's ability to move.
Grass ---> Ground: Grass absorbs nutrients from the ground.
Grass ---> Rock: Rocks can be broken by tree roots.
Grass ---> Water: Plants absorbs water.
Grass -/-> Bug: Slapping insects with plants probably would make them more hungry than injured.
Grass -/-> Dragon: Oh look! Daises! Maybe I can kill the dragon with these! Oops, I was wrong.
Grass -/-> Fire: Fire absorbs organic material.
Grass -/-> Flying: Plants can't do much when a flying animal wants their leaves/fruits.
Grass -/-> Grass: Multiple plants can co-exist with each other without harm in most, but not all, cases.
Grass -/-> Poison: Grass can be poisoned, but poison can not really be destroyed by plants.
Grass -/-> Steel: Metal is hard to break down by organic material.
Ghost ---> Steel: Steel is too sturdy to effectively be possesed.
Ghost ---> Ghost: Supernatural beings are on the same playing field and thus can affect other spirits?
Ghost ---> Psychic: Ghosts aren't natural and are uncomprehensible to a psychic.
Ghost
Normal: Either ghosts can't directly affect the lives of mortals or the programmers wanted to screw with players to force a stalemate since Normal can't affect Ghost either.
Ghost -/-> Dark: Dark characters are evil, and thus if ghosts are considered evil (as most of the "scary" ghost pokemon imply) then evil has a harder time being affected by evil than good (other stuff).
Flying ---> Bug: Most likey relates to the beta "Bird-type", since birds eat bugs.
Flying ---> Fighting: Animals that fly have an advantage in evasiness when compared to land-dwellers since their playing field is essentially in three-dimensions.
Flying ---> Grass: Bird nests, tree branches being perches, plants being habitats etc.
Flying ---> Steel: Cars beat birds and bugs
Flying -/-> Electric: Physical attacks aren't effectice against electricity, especially if the animal can have paralysis from a shock and drop to the ground from the air.
Fire ---> Bug: Bugs don't last long when burnt.
Fire ---> Grass: Fire burns plants.
Fire ---> Ice: Heat melts ice.
Fire ---> Steel: Fire can warp steel and can remove some of its strength
Fire -/-> Dragon: Dragons are supposed to breathe fire, so fire doesn't harm them badly.
Fire -/-> Fire: Fire can't harm fire.
Fire -/-> Rock: Rocks aren't overly affected by fire.
Fire -/-> Water: Technically you can burn water to make steam, but it's not very effective in an open enviornment (unless it's at a island volcano or something)
Fighting ---> Dark: Bad guys usually get punched by
Captain Falcon the heroes in stories.
Fighting ---> Ice: Ice can be crushed with solid punches, but it's kind of pointless in real life.
Fighting ---> Normal: Normal people easy to beat up by strong idiot. *grunts*
Fighting ---> Rock: Fighters can crush rocks, IN FILMS
Fighting ---> Steel: Fighters can bend metal,
in their dreams IN FILMS
Fighting -/-> Bug: Fighters usually aim at large targets and have difficulty hitting a specific, small area.
Fighting -/-> Flying: Fighters are usually in close-range combat, and flying animals easily can get out of range by moving vertically.
Fighting -/-> Poison: Fighters usually are pumped and hyper, allowing poison to course through more rapidly and poison isn't really that easy to punch to oblivion if you ask scientists.
Fighting -/-> Psychic: The fighters see how smart the psychics are and get weakened by depression, recolleting how they never could ace that math test and become a vetrinarian for their life long dream to save poor little puppies lives.
ok, the psychics predict what the fighter will do and chose a method to not be as injured.
Fighting
Ghost: Mortals can not harm immortals with petty things such as mere strength fool, mwah hah hah hah.
Electric ---> Flying: Paralysis from shock can result in a bird plummeting towards its
death faint.
Electric ---> Water: Electricity can move faster and course through water quicker than air.
Electric -/-> Dragon: Thick hides and large size dampen the effects of lightning.
Electric -/-> Electric: Electricity can not be electricuted. lol
Electric -/-> Grass: Well, trees do survive lightning strikes. Although maybe it should occasionally result in a burn status in the next generation.
Electric
Ground: The ground can absorb electricity.
Dragon ---> Dragon: Their high defense is only rivaled by their attack power, which can break another dragon's hide.
Dragon -/-> Steel: Swords and tales of medieval times. Don't know why Steel isn't super-effective by that logic though.
Dark ---> Ghost: Dark minds can do more damage than evil spirits? Should be reversed honestly. Since ghosts "live" in the darkness.
Dark ---> Psychic: Obviously to give Psychic a weakness of some sort, but I see it as the unearthly power that pure psychic souls can not master.
Dark -/-> Dark: Darkness can not be made more dark than no light, and thus can only be "spoiled" by more darkness if there is light. IMO this should actually be an immunity matchup like Normal vs Ghost.
Dark -/-> Fighting: Evil masterminds aren't very strong
once you defeat their henchmen.
Dark -/-> Steel: Metal can not be evil.
Bug ---> Dark: Roaches and what not live in the dark and thus know all of it's secrets and places to take advantage of.
Bug ---> Grass: Aphids, weevils, and other insects prey on plant parts.
Bug ---> Psychic: Bugs can be distracting and can take away from a being's train of thought.
Bug -/-> Fighting: Sure the bug can dodge the blows of a fighter, but it takes time for the bug to attack since it can only stay in one spot for so long when vulnerable.
Bug -/-> Fire: A bug isn't going to do much with a fire besides commit suicide.
Bug -/-> Flying: Again referring to the beta "Bird-type". attacking your predator is not a bright idea.
Bug -/-> Ghost: Bugs are close to "being normal" and thus since they seem somewhat unearthly [but not really] they have some affect on ghosts.
Bug -/-> Poison: Insect spray, 'nuff said.
Bug -/-> Steel: Bugs can not burrow or damage steel, plus cars turn them into nice juicy, oozing pancakes.
All I can say is Dark type is a mess, and I have to lol since I was ninja'd by 11 posts.