Psionics

Psionics is similar to magic, in that it is the ability to do shit that the laws of physics say you shouldn't, but is considered more inherently "science fictiony" than magic, which is seen as the realm of fantasy. See, back when fantasy and science fiction were first getting divorced, serious people called "parapsychologists" thought psionics might be real science, and the CIA offered millions of bucks available for anyone who could give Team Yankee psychic spies they could sic on the Soviet. No, seriously; Cambridge University awarded Carl Lynwood Sargent a fucking doctorate in that. Those millions of bucks over fifty or so years came up with jack shit, but by then everyone from Jedi to dragon-riding girls had psychic powers and they're not gonna let real science stop 'em from being awesome.

The general definition of psionics is that it is a power that stems from the user's mind, and as such it tends to focus more on mental effects; telepathy, mind control, hallucinations/illusions and so forth. Thematically, psionics is magic stripped of the traditional religious/shamanistic flavor, which means that psychics don't use magic words, magic wands, spellbooks, don't summon demons, don't draw pentagrams on the floor, don't do human sacrifice, etc. They just put their fingers to their heads and maybe squint their eyes a little.

Dungeons & Dragons

Psionics has a long tradition in Dungeons & Dragons. Two of its most iconic aberrations, the Aboleth and the Illithid, are defined by their connection to it (or to magic, depending on edition). However, it's long been the black sheep, to the point that Gary Gygax himself thought that it was a bad idea to include it.

Seriously, long-running consensus on /tg/ is that Dungeons & Dragons' psionics is cursed - that these books are not RPG supplements, but grimoires of a sadistic cult, playing with your emotions, and to have any D&D psionics book present in the room will ensure you always roll poorly. Another common opinion is that psions in D&D are overpowered. This stems time and time again from game designers trying to make psychic powers something different than spellcasting, and fucking up the game design doing it. But despite all the bitching, Third Edition psionics is still ten times easier to understand than how wizards worked, and not as powerful as a cleric abusing the shit out of using turn/rebuke undead attempts as fuel.

Psionics were the focus of one of the most significant changes between 3E and 3.5 (with D20 Modern between the strange middle of the two). In contrast to the previous edition, 3.5e psionics are essentially just a casting system that uses Power Points instead of Vancian Casting, and have a side focus on a “psionic focus” resource that makes you pick between remaining focused to get passive bonuses and expending the focus to get temporary bigger bonuses and/or perform unique actions at the cost of losing the passive bonuses till you spend the actions to regain your focus. Unlike previous attempts, 3.5 Psionics are well received by people who actually read the rules, but are often wrongly accused of being overpowered by people who missed the (admittedly not very prominent) rule that you can't use more PP than your level on a power. If people say they like psionics, odds are they're refering to this version.

Ironically, 4th edition D&D actually had the easiest, simplest, most well-integrated psionics system seen in D&D to date. In 4e, psions are still mechanically different, but not to game-tangling extents: psionic classes don't get Encounter powers. Instead, they get a much larger array of at-will powers and a level-determined amount of "power points". Psionic at-wills feature a mechanic called "Augmentation", where a PC can spend some of its power points to buff up the effect. Psionic powers also place much heavier emphasis on the Psychic and Force damage types, making them much harder to resist for most critters.

Traditionally, D&D psionics was divided into six psionic schools, in a repeat of the magic system:

• Clairsentience covered psionic powers that related to expanded sensory perception. A Psion specializing in this discipline is known as a Seer.
• Psychokinesis covered psionic powers that physically affected the world. A Psion specializing in this discipline is known as a Kineticist.
• Psychometabolism covered psionic powers that modified and mutated the body in various ways. A Psion specializing in this discipline is known as a Egoist.
• Psychoportation covered psionic powers relating to manipulating space. A Psion specializing in this discipline is known as a Nomad.
• Telepathy covered psionic powers relating to direct mental communication. A Psion specializing in this discipline is known as a Telepath.
• Metapsionics covered... well, basically a grab-bag of various powers that didn't mesh into any of the others. Later versions changed this to Metacreativity, focused on making and changing stuff with ecotoplasm. A Psion specializing in this discipline is known as a Shaper.

Dungeons & Dragons initially introduced psionics as just "inherent powers", special abilities you could get if you had really, really lucky rolls. AD&D 2nd edition introduced the first ever psionic class, the Psionicist, which was all about growing in psionic powers. 3rd edition renamed the Psionicist to just the Psion and introduced further psionic classes, many of whom were just specific flavors of psionicist or "psychic versions" of existing classes, like the Soulknife, Erudite, Wilder and Psychic Warrior. 4th edition divided psionics up between three classes - the Psion, Ardent and Battlemind - although the Monk was also considered to use the "Psychic Power Source".

Where magic is affiliated with a great number of magical substances, psionics are affiliated with crystals. The origin for this is uncertain. It's either a holdover from Dark Sun where crystals associated with the psionic Thri-kreen are nearly as potent a material as iron, but far less scarce, and/or new age mysticism's use of crystals.

Third-Party Psi

People who preferred the old way of doing things even if they weren't as good generally didn't like the 3rd edition psionics and its bodybuilding telekinetics.

White Wolf, as you might expect, got their Sword & Sorcery Studios in on this fairly early. First Malhavoc Press had Bruce Cordell do If Thoughts Could Kill. Then the 'Wolf figured, hey, Scarred Lands has these mysterious Ancient Aliens in the Slarecians, so... Anyway, none of this saved the setting, nor the 'Wolf. Did we mention that RPG psi is cursed?

In 2004 Steve Kenson and Chris Pramas responded to this audience with the Green Ronin published Psychics Handbook, taking the general concept of 2nd edition psionics and updating it for 3rd edition D&D and its derivatives. it presents one class, 6 prestige classes, an advanced class for D20 Modern, about 45 skills and almost 50 feats.

Alternity

The psionics system in Alternity would form the basis of its later form in D20 Modern. In Alternity, psionic powers are divided into four broad skills: biokinesis, esp, telekinetics, and telepathy. A character that focuses on psionics is a mindwalker and may purchase skills from all four groups as normal. Psionic characters that are not mindwalkers are called talents, are limited to picking one broad skill, and can only spend points on two of its specialty skills (one to rank 6 and another to rank 3).

D20 Modern

D20 Modern includes Psionics in its core rulebook, albeit as a variant. This is expanded on in Urban Arcana. This is the first time Psionics appeared under Open Gaming License, which may be why the 3.5 incarnation was OGL, since it's clearly derived from this sytem. They're a cross between 3E and 3.5 psionics, using many of fixes of 3.5 psionics but still requiring various attributes for each discipline. Augmenting powers is completely absent from this incarnation and, like spells, powers scale naturally with manifester level.

• Telepath has a bunch of mental powers and gets extra PP from its Charisma. It is, oddly, the only one of the four to get bonus power points for high attribute score, which may be an oversight. Until the final D20 Modern book, Dark Matter, they had virtually no options for offensive powers, especially against mindless creatures like undead or robots, and even with it they're very dependent upon hitting a low will save to be useful in combat. Their sole offensive options beyond that are summoning a gun to shoot people with (this power is not on their table, but does say it's a telepath power in the text) and weak telekinesis. Their power list is the most focused attribute wise, as aside from five exceptions based on wisdom (one a cantrip, and one utter crap) all their powers with saving throws are based on Charisma and others are based on Dexterity or Constitution. They're also the only one with fifth level powers. Qualifying at the earliest possible opportunity requires at least one level in Charismatic Hero due to requiring three skills no other base class has and no occupation offers as bonus skills (let alone all three at once).
• Battlemind is a combination of Psychic Warrior and Soulknife. Since magic items are rare and not expected in D20 Modern, full BAB is rare, and hiding your weapons is more of a concern, mindblades are actually quite decent. Their power list most focuses on buffs, but is very scattered in attribute dependencies. Qualifying at the earliest possible opportunity requires three levels in Strong Hero, due to to a BAB +3 requirement and needing max ranks in Jump, which no other base class has for some inexplicable reason.
• Psionic Agent was introduced in Urban Arcana and focuses on movement powers. They otherwise depend on shooting stuff. Mostly dexterity based, but wants wisdom and intelligence as well for some important powers. Qualifying at the earliest possible opportunity is the most flexible, as it can be done with 1:Fast Hero 3, 2: levels in a combination of Fast Hero and Strong Hero, or 3: a non-charismatic hero, non-smart hero with a starting occupation of military, criminal, adventurer, scavenger, impoverished, on the run, or slave.
• Mesmerist was introduced in D20 Past. They only get a fraction of the normal psionics progression and no other class abilities. Supposedly for low psionics games, this class is Truenamer tier broken since it doesn't actually say what powers it can take as powers known (the example character pulls from the telepath list, but WotC example characters are wrong, often blatantly, more than they are right.). Due to identical skill requirements, it requires Charismatic Hero for earliest entry.

Psionics are also referenced in D20 Future and D20 Apocalypse, but only as special abilities of aliens and mutants. There's a handful of new powers and feat support in d20 Dark Matter, but no new classes. Unlike casters, there is no Psionic Prestige Class to continue advancing after hitting level 10. This role is instead filled by the ability to multiclass and stack power point progression, but it's not as nice a deal since you don't get as many extra castings (four levels of Archmage doubles your casting slots. Four levels of an extra psionic class doesn't even give you an extra casting of a 5th level power.) and don't increase your caster level. Despite this problem and the all attributes thing they're still casters in a system where, despite the many nerfs they got, casters are still king.

Pathfinder

Pathfinder, of course, has its own "psionic system", which it tries to differentiate by using real-world beliefs in psychics and occultism. The end result for all of them but Kineticist was just another set of Vancian magic spells with some components swapped around and using under-supported, proprietary spell lists. One major weakness of the system is that all of these classes (except Kineticist because that doesn't actually cast and maybe Mesmerist because it can remove conditions, fear included, from itself as a swift action and has plenty of non-casting options) can be shut down by giving them a non-harmless emotion effect, allowing even the most basic fear effect to shut them down. It was introduced to the world in the Occult Adventures sourcebook, which was followed by the far-shorter Occult Bestiary, for more psionic-focused enemies, Occult Origins, for how to work psionic stuff into Golarion, and Occult Realms, which does largely the same.

• The Kineticist draws upon an innate ability to manipulate one or more elemental forces and energies through the power of their will.
• The Medium communicates with the spirits of the dead and allows them to possess their body in order to gain temporary powers drawn from the spirit.
• The Mesmerist is a specialist psychic who focuses on mind-controlling powers powers exclusively, essentially a psionics-fueled enchanter & illusionist.
• The Occultist seeks out relics imbued with strong psionic resonance and uses these as a medium to draw upon and channel psionic energy; without these totem-implements, they're all but powerless.
• The Psychic is essentially the Pathfinder version of the Psion: a master of various psychic powers that derives their strength from a fundamental discipline, functioning somewhere between a psionic sorcerer and a specialist wizard.
• The Spiritualist is similar to the Medium, in that its powers stem from a psychic connection to the dead. However, the Spiritualist has a singular bonded spirit, a Phantom, and this entity can carry out most of the fighting for them, using the Spiritualist as a battery to enhance its abilities.

The Classes of Pathfinder 1st Edition
Core Classes:	Barbarian - Bard - Cleric - Druid - Fighter - Monk Paladin - Ranger - Rogue - Sorcerer - Wizard
Advanced Player's Guide:	Alchemist - Antipaladin - Cavalier Inquisitor - Oracle - Summoner - Witch
Advanced Class Guide:	Arcanist - Bloodrager - Brawler - Hunter - Investigator Shaman - Skald - Slayer - Swashbuckler - Warpriest
Occult Adventures:	Kineticist - Medium - Mesmerist Occultist - Psychic - Spiritualist
Ultimate X:	Gunslinger - Magus - Ninja - Samurai - Shifter - Vigilante

This section is based on Third Party and/or Fan Content/Homebrew. Canonfuckers Beware.

However, for those who want the more classic 3.X Experience, 3pp producer Dreamscarred Press also ported forward the Psionics system, with a few new bits. The biggest changes here are the total destruction any remnants of non-transparency between psionics and normal magic beyond their separate knowledge skills and counterspelling nobody uses anyways, replacing XP penalties (which no longer exist in PF) with negative levels on yourself, and ditching the convention of giving names to powers that are the same name as a spells but with ", psionic" tacked on in favor of unique names. This type of psioncs is technically canon in Golarion, as there's a handful of mentions from back when Pathfinder was third party supplements for 3.5.

• The Psion is still here and the primary casty-type with Wizard-tier Discipline specializations. Generalist option has been added, which gives up discipline access (without Expanded Knowledge) in exchange for bonus feats (which explicitly can be used for Expanded Knowledge, though still carry the penalty of being behind in level). No longer gets a psicrystal at first level, instead it gets a feat that can pick any psionic feat, including the one that gives you a psicrystal (a slight tweak that makes them more customizable). Further books added variant specializations akin to what Wizards sub-schools got, with the generalist getting a (much nerfed) version of Erudite.
• The Wilder is also a caster, but a much more offensive sort who has to balance how they use their surges and the risk of Psychic Enervation.
• The Psychic Warrior is a mid-tier Psionics character, who blends together Fighter-Tier feat availability with psychic focuses based on how you want them to work.
• The Soulknife is kinda Psionic in name only. The blade itself is their sole power, and then they get Blade Skills (talents) that give their blades new uses and perks. Thankfully they have an archetype giving them limited Psionic powers.
• The Dread is a class based on being big and scary and touching things in order to inflict all sorts of conditions on them.
• The Marksman is a low-tier Psionic class that focuses more on shooting things like a Ranger.
• The Cryptic is the Psionic Rogue, only with strange ways to mess with people by screwing with reality in small ways.
• The Aegis is kind of like the opposite number to the Soulknife: rather than making weapons, these guys make suits of psionic armor (available in either barely-there skin, average armor, or heavy behemoth armor) and selecting a set of mods to give their armor special functions.
• The Tactician is a psionic mastermind, a combat leader with better powers. They focus on gathering allies into a collective consciousness and spreading out bonuses and benefits to the members when necessary.
• The Vitalist is the answer to anyone complaining that Psionics has shit healing. Like the Tactician, they work based on a collective and spread out any heals among the party. Unlike most healer classes, they're actually quite acceptable at things other than healing. Psionics makes it really easy to get powers from another list and one options built into the class focuses on vampiric healing.

Also introduced was the "seventh path", a new discipline to address the lack of a necromancy counterpart.

• Athanatism covers psionic effects that deal with spirits and ghosts, essentially psionic necromancy. A psion specializing in athanatism is known as a Conduit.

Warhammer 40k

Warhammer 40,000 is the premier /tg/ example of the "psionics is just space magic!" design. Psionics in the 40kverse derives from the ability to mentally tap into the Warp, a parallel universe of pure, unbridled emotional energy, where thought and matter are interchangeable. As all most minds are inherently linked to this dimension, psykers just have the ability to exploit that link, psionics consists of either using the Warp as a way to directly connect to and influence the minds of others, or drawing Warp energy into the material universe and using it to temporarily rewrite the laws of reality.

Psionics in 40k is really just fantasy magic because it has most of the classic tropes: rituals, magic circles, demon summoning, magic words, etc. But Games Workshop wants it to have a veneer of sci-fi so it still gets called psionics instead of wizards in space like it really is. Actual "sorcerers" in the setting are psykers who have made pacts with the Chaos Gods and wield what the Imperium considers black magic.

In most fantasy and sci-fi settings, being a wizard is generally awesome, but being a psyker in WH40K is more trouble than it's worth. If you are born a psyker but don't get training, you will be prone to madness or even demon possession. If the Imperium finds you, they'll rip you from your family and community (and maybe exterminate them for safety) and ship you off to Earth to be judged if you're worthy of being turned into a slave. If you are judged capable of controlling your powers, you will be trained and turned into a "sanctioned psyker", which means you'll be a slave for life. Psykers, even the sanctioned ones, don't get to live free lives selling their talents to whoever can pay. They have to serve the Imperium either as psychic telegram operators or as psychic artillery on the battlefield. And if you're judged incapable of serving these roles because you're too weak, you will be sacrificed to the Emperor so that he can keep his magic lighthouse lit.

Star Wars

The Force in Star Wars is just a fancy name for psionics. Ironically, although treated like magic, it functions more like classic psionics; Force Users predominantly produce mental effects (the famous "Jedi Mind Trick" is basically a psychic Charm Person spell) and telekinesis, although there are more exotic powers as well - most of these tend to be Dark Side, though. Jedi are often called "space wizards" by the fans, but ironically they mostly fight with their lightsabers, only occasionally spicing up their fencing skills with a few telekinetic jabs or amazing jumps.

Unfortunately for the person who wrote the above, this isn't how the Force works. The Force has a consciousness and will of its own, making Force abilities more akin to divine magic than psionics.

Unfortunately the person who wrote the second paragraph has drunk too deep from the cup of cartoon, Disney Star Wars nonsense. No one in the galaxy knows how the Force works. The Force definitely does not come from something ridiculous like a single being with two children, representing the Force in a way that totally fumbles George Lucas' original vision. (Even though the single being with two children was made when George was still running things before the dark times of Disney) No; that would be silly. It's whitewashed Buddhism in space, y'all. If you think hard, you can lift stuff with your mind, or fool people by waving your hand. If you're a big meanie, you can shoot lightning from your hands. Don't overthink it.

Star Trek

Ironically, despite the vast amount of weird space shit that pops up in Star Trek, psionics isn't very common. Vulcans have the ability to telepathically probe and manipulate minds through a meditative trance that requires physical contact, the infamous "Vulcan Mind Meld", whilst Betazoids are characterized as a telepathic species, although half and occasionally even quarter Betazoids are empathic (emotion sensing). Other noteworthy telepathic species include the Talosians and the Ocampa.