With the news of the new Fairy type, there are questions about how it will be defined as Pokemon type. And there also seems to be some debate over how exactly you differentiate between Psychic, Ghost, and Dark type moves. So I thought I would write this thread here for my theories on how these three other types could be defined.
First Psychic types. Psychic types are Pokemon that use psychic powers to survive. And on that note, let's discuss what is meant by "psychic". The term psychic is actually very vague, and can be used to name a whole bunch of different and strange abilities. But there is a way to break it down. It comes from those people in that believe in the existence of psychic powers in real life. It doesn't matter if you do or not, this is how they define it.
The term psychic is merely the word that encompasses lots of different phenomenon. After that, psychic powers split into two broad categories, Extra Sensory Perception (ESP) and Psychokinesis (PK). ESP is about gaining information via methods other than the five senses. This includes things like precognition (seeing the future, employed by Alice Cullen of Twilight), and telepathy. Other abilities under ESP include clairvoyance. It's French for "clear seeing" and involves having visions of past or present events. But note that this information is ONLY interpreted through the sense of sight. There is no sound, no smell, no other sense. This is in contrast to clairaudience (French for "clear hearing") in which the same thing occurs, but only through sound.
PK involves moving things with your mind, like telekinesis. The metaphor used to explain the difference between ESP and PK is that they are different types of radio equipment. ESP is like a radio receiver, it picks up information from the world but does not put out. PK on the other hand is a radio transmitter, it puts signals out to shake up the world around it, but doesn't take in. A person can manifest forms of ESP, PK, or both. Psychic Pokemon are the same way. I think all Psychic types are proficient at some form of PK, considering they use those powers to defend and attack. For example, Golduck. It may not be the type, but it has the powers, and those manifest as telekinesis.
Other species are able to use both. For example, Sabrina's Kadabra was able to form a telepathic link with her. That qualifies as a form of ESP, being able to read the minds of others. At least I think. In any case, other Psychic species have developed forms of ESP, like Natu and Xatu, who see the future (precognition) or Solrock and Lunatone, who can read the minds of enemies.
These psychic abilities would mean that Psychic types would need different brain structures. In particular, the frontal lobe area of the brain would probably be much more developed. The frontal lobe is, as the name suggests, at the very front, and controls the most complex functions like judgement, personality, so on and so forth. This would probably mean that psychic types have a much higher average IQ than other types. Not that Pokemon are stupid, quite the opposite. It's just that Psychics would be even smarter on average. And because they develop their minds so much, their bodies are probably not all that strong. They don't necessarily resist Fighting type attacks so much as they can prevent those attacks from hitting, because they attack the mind, and stop fighters before they get close. Their weakness to Bug could be explained as Bug-type brains having a difference in structure, a difference that confuses Psychic types, as their usual techniques of mental manipulation don't work quite right. This leaves them open to Bug attacks.
Ghost types were names so because of their initial resemblance to ghosts. Pokemon scientists are probably not willing to admit they are real ghosts. Science and magic may exist side by side in the world, but I don’t think the researcher community will acknowledge it. So whether or not the species ARE ghosts doesn’t really matter to researchers.
The signature ability of most Ghost types is that while they have normally solid bodies, they can become intangible (pass through objects). My theory is that Ghost Pokemon perform their tricks by manipulating dark matter and dark energy. Most matter is bright matter. But dark matter does not reflect light, so it could fill in the gaps for Ghost types. Species like Dusclops are exempt from intangibility because it has a black hole inside of it, and that thing probably would become unstable in it tries to pass through something.
Dark types are interesting, and perhaps the hardest type to pin down. What do we know about Dark types? They tend to employ trickery and deceit to win. That’s what most Dark moves are like. On average, the only stat that’s impressive is attack.
The fact that they turn to tricks to primarily overcome enemies says something about them. I think it says that they aren’t all that durable, and deep down they know it, even if they won’t admit it. I am speaking of course of pure Dark types. Their bodies aren’t built for stamina, and can’t take hits very well, so they resort to tricks and deception to get an edge over enemies because they won’t try straight offense. With their attack being the only thing above average, that means they try to weaken opponents and hit hard and fast so they avoid long battles and direct damage. This explains their particular weakness to Fighting types. Fighting types have very well developed and strong muscles. They hit very hard. So if they get a direct hit to a Dark type, it is really, really going to hurt them.
Another feature which might define Dark types is that they are probably nocturnal, and perhaps a bit on the aggressive side, or maybe just aren’t given to pleasant temperaments. Their resistance to Psychic type could also be for the same reason that Bug types may work against Psychic types, brain structure differences that throw off Psychic types, which are used to assault brains with particular layouts.
Another explanation is that Dark types, like Psychics, are possessed of a greater average IQ than other types. This would certainly fall in line with their choice of deception. Their greater mental abilities allow them to fend off mental attacks. Or it could be both. Also, considering that some Dark type attacks involve a pulse of dark-looking energy, I want to say that perhaps Dark types have some capacity for manipulating dark matter and dark energy like Ghost types. Of course, their capacity for using it isn't as great as the Ghost types, which is one reason why Dark types are not gifted with intangibility.
What do you all think? Is it good?