[RPG] psionics


Psionics is a source of power that originates from
within a creature’s mind, allowing it to augment its
physical abilities and affect the minds of other
~from Unearthed Arcana: Awakened Mystic

I'm trying to figure out what exactly psionics is in D&D 5e. So it's some vague power derived from the creatures' minds. OK. But then how can it "augment […] physical abilities"? Shouldn't it specifically be things related to the mind?

For instance, Lethal Strike is an ability that is being playtested at the moment for the newly created Mystic of the Order of the Immortal. This ability allows a Mystic to spend up to 5 psi points to add extra damage to an attack. But this isn't psychic damage — it's damage of the same type as the attack. So where's the mental part coming in?

If the claim is that through mental discipline/ ability a psionic creature can artificially enhance their own bodies (and presumably detriment the bodies/ physical abilities of enemies), then what exactly is the difference between Psionics and Ki (in terms of what users can actually do) — other than that Psionics is clearly better because it includes some mental abilities as well? Or in fact, what's the difference between Psionics and Magic other than that Magic is clearly better, being inherently vaguer?

What I'm looking for is an in-setting explanation of what Psionics is, including what it can and can't be used to do. And how this compares and contrasts with other power sources like Ki and Magic.

Best Answer

This answer was correct as of the question's asking. As later revisions to the UA Mystic came along, they invalidated this answer. This answer contains the latest official description of psionics.

In the D&D podcast of July 10 Mike Mearls describes it, starting at about 14:00, as

The power of the mind. It is a power source that comes from within... it derives from the opening of the mind's eye....

He then goes on to discuss how the Far Realm in D&D cosmology "bumps into" our planes and "can twist reality a little bit." Continuing,

What happens is, if you're psionic your mind's eye is open and you see the underlaying structure of this reality in a way that other people don't. And by drawing on your willpower and your own mental energy you can exert changes to the structure of reality around you- or you can perceive things.... Or you can understand your body and manipulate your muscles beyond what would normally be possible.

He goes on to stress the separate nature of psionics and magic, describing how they've intentionally renamed many psionic abilities to avoid spell-names.

As for the distinction with ki, the class description of a monk specifies that monks have made a specialized study of "an element of the magic that suffuses the multiverse--specifically, the element that flows through living bodies." (PHB p.76)

So monks are using one form of the magical energy that's native to the multiverse; mystics are in tune with things coming from farther out.

Related reading (from comments):

Psionics (role-playing games) - Wikipedia

Why do psionics suck? - AngryGM

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