Spells Through The Ages – ESP and Clairvoyance

The 2nd-level D&D wizard spell, ESP, has a somewhat interesting pedigree. For starters, it's oddly named -- just a 3-letter acronym, one which is not actually defined anywhere in OD&D, 1E, etc. Secondly, it's a bit of a misnomer; "ESP" is properly an umbrella term for a multitude of para-psychological powers, like telepathy, clairaudience, and clairvoyance (link). While the D&D ESP power itself is most like the first of those (3E renamed it "detect thoughts", a phrase briefly used in the OD&D text; perhaps "read minds" would be the best name for it), each of those D&D magics will be addressed below (they are all linked in the initial rules).

Inasmuch as D&D is an artifact of the pop sensibilities of its time, perhaps it shouldn't be too surprising that ESP (extrasensory perception, of course) should be familiar to its readers -- in the wake of the 1960's "New Age" and "Human Potential Movement", there was a resurgence of interest in expanding one's consciousness by a number of means, and hope for investigating and harnessing it for practical real-world purposes. In fact, it was in the same decade as D&D's first publication that the governments of Russia, China, and the U.S. all founded research facilities dedicated to using ESP-like powers for military objectives (to the tune of tens of millions of dollars in the U.S. for at least a few decades -- see information on the "Stargate Project" and "remote viewing" generally.) Should your fantasy-world kings and archpriests be funding colleges of magic for the same purpose? Let's see:

Original D&D

ESP: A spell which allows the user to detect the thoughts (if any) of whatever lurks behind doors or in the darkness. It can penetrate solid rock up to about 2' in thickness, but a thin coating of lead will prevent its penetration. Duration: 12 turns. Range: 6"

Clairvoyance: Same as ESP spell except the spell user can visualize rather than merely pick up thoughts.

Clairaudience: Same as Clairvoyance except it allows hearing rather than visualization. This is one of the few spells which can be cast through a Crystal Ball (see Volume II).

ESP is 2nd-level, while the other two spells are 3rd-level. From a lot of personal use with medallions of ESP (the magic item in Vol-2) in contexts like the Dungeon! boardgame and AD&D DMG solo-dungeoneering rules, I feel like I've got a pretty good grip on the purpose of this short-range spell -- you use it to detect what's lurking on the other side of a door, before you burst in, kind of like a super-powered "hear noise" option. According to this text, the clairvoyance and clairaudience spells work about the same, but seem intended to give more complete information about the area behind the door. (Clearly of limited range: consider powers given to certain gods in OD&D Sup-IV tagged with a modification like, "Clairvoyance (no range limitations)": p. 23, 25, 43.)

B/X D&D Rules

ESP 
Range: 60'
Duration: 12 turns
 
This spell will allow the caster to "hear" thoughts. The spell caster must concentrate for one full turn in one direction to "hear" the thoughts (if any) of a creature within range. Any single creature's thoughts may be understood (regardless of the language), but if more than one creature is in the line of "hearing", a confused jumble of thoughts will be "heard". In this case, the caster may concentrate in that direction for an extra turn to sort out the jumble and concentrate on one creature. The spell caster may "hear" through 2 feet of rock, but a thin coating of lead will block the ESP. The thoughts of the undead (if any) cannot be "heard" by means of this spell.

Clairvoyance 
Range: 60'
Duration: 12 turns
 
This spell allows the user to see an area through the eyes of any single creature in it. The creature must be in the general direction chosen by the caster and in range. The spell is blocked by more than two feet of rock or a thin coating of lead. "Seeing" through a creature's eyes takes one full turn, after which the caster can change subjects.

The way these rules are organized, the 2nd level ESP is in Tom Moldvay's Basic D&D Set; the 3rd-level clairvoyance is in Dave Cook's Expert D&D Set (with clairaudience being discarded from those rules). ESP has effectively the same range & duration; it picks up complications over multiple targets, and an inability to read the minds of the undead. Clairvoyance is given greater specificity than in OD&D; the range & duration are the same as ESP (only given by implication in Vol-1), and Cook invents a detail that it functions by looking through another creature's eyes. One the one hand, that's sort of in spirit of "Same as ESP spell except the spell user can visualize" (per OD&D above); but on the other hand, that's generally not what's implied by the terms "clairvoyance" or "remote sensing" (see links above). This interpretation will not be re-used by any other version of the D&D rules.

AD&D 1st Ed. 

ESP (Divination)
Level: 2
Range: ½"/level, 9" maximum
Duration: 1 round/level
Area of Effect: One creature per probe
Components: V, S, M
Casting Time: 2 segments
Saving Throw: None

Explanation/Description: When an ESP spell is used, the caster is able to detect the surface thoughts of any creatures in range - except creatures with no mind (as we know it), such as all of the undead. The ESP is stopped by 2 or more feet of rock, 2 or more inches of any metal other than lead, or a thin sheet of lead foil. The magic-user employing the spell is able to probe the surface thoughts of 1 creature per turn, getting simple instinctual thoughts from lower order creatures. Probes can continue on the same creature from round to round. The caster can use the spell to help determine if some creature lurks behind a door, for example, but the ESP will not always reveal what sort of creature it is. The material component of this spell is a copper piece.

Clairaudience (Divination)
Level: 3
Range: Special
Duration: 1 round/level
Area of Effect: Special
Components: V, S, M
Casting Time! 3 segments
Saving Throw: None

Explanation/Description: The clairaudience spell enables the magic-user to concentrate upon some locale and hear in his or her mind whatever noise is within a 6" radius of his or her determined clairaudience locale center. Distance is not a factor, but the locale must be known, i.e. a place familiar to the spell caster or an obvious one (such as behind a door, around a corner, in a copse of woods, etc.). Only sounds which are normally detectable by the magic-user can be heard by use of this spell. Only metal sheeting or magical protections will prevent the operation of the spell. Note that it will function only on the plane of existence on which the magic-user is at the time of casting. The material component of the spell is a small silver horn of at least 100 g.p. value, and casting the spell causes it to disappear.

Clairvoyance (Divination)
Level: 3
Range: Special
Duration: 7 round/level
Area of Effect: Special

Explanation/Description: Similar to the clairaudience spell, the clairvoyance spell empowers the magic-user to see in his or her mind whatever is within sight range from the spell locale chosen. Distance is not a factor, but the locale must be known - familiar or obvious. Furthermore, light is a factor whether or not the spell caster has the ability to see into the infrared or ultraviolet spectrums. If the area is dark, only a 1" radius from the center of the locale of the spell's area of effect can be clairvoyed; otherwise, the seeing extends to normal vision range. Metal sheeting or magical protections will foil a clairvoyance spell. The spell functions only on the plane on which the magic-user is at the time of casting. The material component of the spell is a pinch of powdered pineal gland from a human or humanoid creature.

ESP is about the same as in OD&D. As usual for 1E, range & duration are transformed from fixed values to level-dependent variables, and at least two oddities arise from that -- first, it's one of only two in the entire ruleset that are tagged with a "maximum" range limit to its formula for range (the other being ventriloquism); and second, it's stepped into the confusing mess over time-units, in that the "1 round/level" duration is probably actually shorter than the text requirement of probing "1 creature per turn" (since 10 rounds = 1 turn in these rules).

It's in the clairvoyance/clairaudience pair that things get a bit more interesting. Here, Gygax has listed them both as "Range: Special" and written in the text "Distance is not a factor". So... that means you can see infinitely far away (as long as "familiar or obvious")? That's certainly not how I (or Dave Cook) would have read the OD&D text, and even here it's a bit cursory and easy to miss. I can see this causing a lot of interpretive arguments over what counts as "obvious" (The interior of the citadel I'm viewing from miles away, or simply know about? The center of the dungeon in that mountain I've been told exists?) No errata notes are given in the DMG. We might wonder if this expanded power takes some thunder away from the crystal ball magic item (originally the only infinite-distance detection power in the game; if clairaudience could do the job all by itself, then it wouldn't need casting through a crystal ball, as noted for OD&D above).

The fact the clairvoyance may work less well than ESP in the standard dungeon setting, because most rooms may well be dark in the first place, is noted for the first time here and addressed with a special "see 1 inch even in the dark" power (which I think is kind of fiddly). Also, is it a little strange that clairaudience is given a fairly pricey 100gp material component that gets disappears, but not clairvoyance?

AD&D 2nd Ed.

ESP
(Divination)
Range: 0
Duration: 1 rd./level
Area of Effect: 5 yds./level (90 yds. maximum)
 
When an ESP spell is used, the caster is able to detect the surface thoughts of any creatures in range--except for those of undead and creatures without minds (as we know them). The ESP is stopped by 2 feet of rock, 2 inches of any metal other than lead, or a thin sheet of lead foil.

The wizard employing the spell is able to probe the surface thoughts of one creature per round, getting simple instinctual thoughts from lower order creatures. Probes can continue on the same creature from round to round or can move on to other creatures. The caster can use the spell to help determine if a creature lurks behind a door, for example, but the ESP does not always reveal what sort of creature it is. If used as part of a program of interrogation, an intelligent and wary subject receives an initial saving throw. If successful, the creature successfully resists and the spell reveals no additional information. If the saving throw is failed, the caster may learn additional information, according to the DM's ruling. The creature's Wisdom adjustment applies, as may additional bonuses up to +4, based on the sensitivity of the information sought.

The material component of this spell is a copper piece.

Clairaudience
(Divination)
Range: Unlimited
Duration: 1 rd./level
Area of Effect: 60-ft. radius

The clairaudience spell enables the wizard to concentrate upon some locale and hear in his mind any noise within a 60-foot radius of that point. Distance is not a factor, but the locale must be known--a place familiar to the spellcaster or an obvious one (such as behind a door, around a corner, in a copse of trees, etc.). Only sounds that are normally detectable by the wizard can be heard by use of this spell. Lead sheeting or magical protections prevent the operation of the spell, and the wizard has some indication that the spell is so blocked. The spell creates an invisible sensor, similar to that created by a crystal ball spell, that can be dispelled. The spell functions only on the wizard's current plane of existence.

The material component of the spell is a small horn of at least 100 gp value.

Clairvoyance
(Divination)
Range: Unlimited
Duration: 1 rd./level
Area of Effect: Line of sight

Similar to the clairaudience spell, the clairvoyance spell empowers the wizard to see in his mind whatever is within sight range from the spell locale chosen. Distance from the wizard is not a factor, but the locale must be known--familiar or obvious. Furthermore, light is a factor, as the spell does not enable the use of infravision or magical enhancements. If the area is magically dark, only darkness is seen; if naturally pitch dark, only a 10-foot radius from the center of the spell's area of effect can be seen. Otherwise, the seeing extends to the normal vision range according to the prevailing light. Lead sheeting or magical protection foils a clairvoyance spell, and the wizard has some indication that it is so blocked. The spell creates an invisible sensor, similar to that created by a crystal ball spell, that can be dispelled. The spell functions only on the wizard's current plane of existence.

The material component is a pinch of powdered pineal gland.

So here's Dave Cook's second go at interpreting the works of Gygax. For the first time, Cook mentions a saving throw for ESP, in the specific case of an extended interrogation for specific information. For clairvoyance/clairaudience, the range is here explicated by Cook now listing them as "Range: Unlimited", so there's no question about how far they can function -- really far. They're in a very small group with that designator for range in this ruleset (the others being wish, limited wish, and the new spells sending and demand).

D&D 3rd Ed.

Detect Thoughts
Divination [Mind-Affecting]
Level: Brd 2, Knowledge 2, Sor/Wiz 2
Components: V, S, F/DF
Casting Time: 1 action
Range: 60 ft.
Area: Quarter circle emanating from the character to the extreme of the range
Duration: Concentration, up to 1 minute/level (D)
Saving Throw: Will negates (see text)
Spell Resistance: No

The character can detect surface thoughts. The amount of information revealed depends on how long the character studies a particular area or subject:

• 1st Round: Presence or absence of thoughts (from conscious creatures with Intelligence scores of 1 or higher).
• 2nd Round: Number of thinking minds and the mental strength of each.
• 3rd Round: Surface thoughts of any mind in the area. A target’s Will save prevents the character from reading its thoughts, and the character must cast detect thoughts again to have another chance. Creatures of animal intelligence (Int 1 or 2) have simple, instinctual thoughts that the character can pick up.

Note: Each round, the character can turn to detect thoughts in a new area. The spell can penetrate barriers, but 1 foot of stone, 1 inch of common metal, a thin sheet of lead, or 3 feet of wood or dirt blocks it.

Arcane Focus: A copper piece.

Clairaudience/Clairvoyance
Divination
Level: Brd 3, Knowledge 3, Sor/Wiz 3
Components: V, S, F/DF
Casting Time: 1 action
Range: See text
Effect: Magical sensor
Duration: 1 minute/level (D)
Saving Throw: None
Spell Resistance: No

Clairaudience/clairvoyance enables the character to concentrate upon some locale and hear or see (the character's choice) almost as if the character were there. Distance is not a factor, but the locale must be known—a place familiar to the character or an obvious one. The spell does not allow magically enhanced senses to work through it. If the chosen locale is magically dark, the character sees nothing. If it is naturally pitch black, the character can see in a 10-foot radius around the center of the spell’s effect. Lead sheeting or magical protection blocks the spell, and the character senses that the spell is so blocked. The spell creates an invisible sensor that can be dispelled. The spell functions only on the plane of existence the character is currently occupying.

Oh 3E, I wanted to love you so terribly much. But here you've taken the old ESP, renamed to detect thoughts (which you can sort of sympathize with, although I can think of better names) and made a whole complicated piece of drama out of it. Now you've got this picky-itsy rule on what you pick up each round to distinguish between the "something's over there" and the "useful mental information" aspects of the spell. You've also got this big friggin' table with 10 rows to handle the fact that someone threw "mental strength" in as a detail in the 2nd round of scanning. That kind of thing totally burns my chaps, because it guarantees that the game stops and everyone flips through the PHB to this page every time the spell gets used. Hey, how about instead, I don't know, just directly declare the Intelligence ability score of the creature? Or cut it to 3 categories (dumb, average, genius)? Or skip the whole thing entirely?

Although in its defense, detect thoughts (nee ESP)  looks the way it does because all the 3E "detection" spells were synchronized to have this same kind of 3-rounds-of-increasing-effect and a table-of-strengths format. This includes: detect animals or plants, detect evil (et. al.), detect magic, detect secret doors, detect snares and pits, detect thoughts, and detect undead. And that was spawned by a little addition to detect magic back in the 1E DMG that allowed you get to get some extra information on a scan ("This spell detects the intensity of the magic (dim, faint, moderate, strong, very strong, intense) and there is a 10% chance per level of the caster that the type (abiuration, alteration, etc.) can be found as well..."; 1E DMG p. 44). Even the 3E detect thoughts "mental strength" table is basically derived from the similar table you'd find at the the start of the 1E Monster Manuals. On second thought -- that's not so much a defense, the fact that all of these detection spells were allowed to get so crazy complicated should be more of a deeper condemnation.

But meanwhile -- The clairaudience/clairvoyance pair has been collapsed to a single spell (again, you can sort of see why, but you just fixed the ESP name oddity and then made this the new clunkiest spell name in the system). Here the designers have stripped out Dave Cook's 2E clarification of "Range: Unlimited"... now you're back to 1E-style text with "Range: See text", and needing to pick up on the "Distance is not a factor" text and interpret it correctly.

D&D 3.5 Ed.

Detect Thoughts
Divination [Mind-Affecting]
Level: Brd 2, Knowledge 2, Sor/Wiz 2
Components: V, S, F/DF
Casting Time: 1 standard action
Range: 60 ft.
Area: Cone-shaped emanation
Duration: Concentration, up to 1 min./level (D)
Saving Throw: Will negates; see text
Spell Resistance: No

You detect surface thoughts. The amount of information revealed depends on how long you study a particular area or subject.

• 1st Round: Presence or absence of thoughts (from conscious creatures with Intelligence scores of 1 or higher).
• 2nd Round: Number of thinking minds and the Intelligence score of each. If the highest Intelligence is 26 or higher (and at least 10 points higher than your own Intelligence score), you are stunned for 1 round and the spell ends. This spell does not let you determine the location of the thinking minds if you can’t see the creatures whose thoughts you are detecting.
• 3rd Round: Surface thoughts of any mind in the area. A target’s Will save prevents you from reading its thoughts, and you must cast detect thoughts again to have another chance. Creatures of animal intelligence (Int 1 or 2) have simple, instinctual thoughts that you can pick up.

Each round, you can turn to detect thoughts in a new area. The spell can penetrate barriers, but 1 foot of stone, 1 inch of common metal, a thin sheet of lead, or 3 feet of wood or dirt blocks it.

Arcane Focus: A copper piece.


Clairaudience/Clairvoyance
Divination (Scrying)
Level: Brd 3, Knowledge 3, Sor/Wiz 3
Components: V, S, F/DF
Casting Time: 10 minutes
Range: Long (400 ft. + 40 ft./level)
Effect: Magical sensor
Duration: 1 min./level (D)
Saving Throw: None
Spell Resistance: No

Clairaudience/clairvoyance creates an invisible magical sensor at a specific location that enables you to hear or see (your choice) almost as if you were there. You don’t need line of sight or line of effect, but the locale must be known—a place familiar to you or an obvious one. Once you have selected the locale, the sensor doesn’t move, but you can rotate it in all directions to view the area as desired. Unlike other scrying spells, this spell does not allow magically or supernaturally enhanced senses to work through it. If the chosen locale is magically dark, you see nothing. If it is naturally pitch black, you can see in a 10- foot radius around the center of the spell’s effect.

Clairaudience/clairvoyance functions only on the plane of existence you are currently occupying.

Arcane Focus: A small horn (for hearing) or a glass eye (for seeing).

Okay, we can see a few things here that 3.5 actually did improve on -- or at least back-pedaled on some of the more ridiculous design decisions made in 3E. One is that the detect thoughts (ESP) big table did get snipped out, and replaced by simply knowing "the Intelligence score" of each target, as I suggested above. A second is that clairaudience/clairvoyance has its range cut down from unlimited (as it was in AD&D 1E-3E) back down to local-usage only, 400 ft. + 40 ft.level (a lot more like it was in OD&D and B/X). So that leaves some legitimate advantage to the higher-level scrying spells and items (crystal balls). At least those are good calls, I think.

Conclusions

So it seems to me like the clairvoyance/clairaudience spells are very powerful, if interpreted as being usable at totally any distance -- subject to arguments over what counts as "familiar or obvious", of course. In fact, I would think that these "remote viewing" spells available to any wizard would come pretty close to eliminating any need for crystal balls or the magic mirror/magic font spells that first popped up in 1E Unearthed Arcana and were kept in all later editions. Although: I can imagine in any edition other than 2E that someone might easily overlook the "Distance is not a factor" line and exactly what that implies. I have to admit, even with all this textual history, I keep coming back to these spells and expecting them to have the same restrictions that ESP did in OD&D.

Am I wrong about that? How powerful is the ESP-clairvoyance-clairaudience trio in your games? Do your players routinely use them to great effect? Have you found it necessary to insert any additional interpretations or limitations (or expansions) to these spells? Inquiring minds want to know.

Edit: One more question --  How do you feel about Cook's being able to understand any creature's thoughts "regardless of the language" that appears only in his Expert rules? Fair game or too powerful?

Edit: Added the look at the 3.5 edition versions. Thanks to commentator Monkapotomus for the heads-up on that.

Edit: See also my friend Paul's assessment of the clairvoyance and ESP suite of spells.