Telepathy

Telepathy, sometimes referred to as ESP, is a passive property in NetHack that allows you to detect non-mindless monsters, regardless of whether or not you can physically see them.

Description

The range of unblind extrinsic telepathy is indicated by flags. In comparison, the range of warning is slightly greater, and is indicated by question marks.

Telepathy can be acquired as both an intrinsic and extrinsic property through various means, and function somewhat differently depending on their source. It is possible to have both forms of telepathy independent of each other, with the extrinsic property taking priority over the intrinsic.

• Intrinsic telepathy allows you to detect all non-mindless monsters on the current level, but only while you are blind.
• Extrinsic telepathy allows you to detect all non-mindless monsters within a radius of 8 squares, and additionally displays all non-mindless monsters on the current level while you are blind.

Only three monsters have intrinsic telepathy:

• e floating eye
• h mind flayer
• h master mind flayer

If a mind flayer or master mind flayer is near you while you possess either form of telepathy, they can detect you and will attack you with a long-distance psionic blast for d15 damage; polymorphing into a mind flayer allows you to use this ability with the #monster extended command.

Intrinsic sources

Intrinsic telepathy can be acquired through the following methods:

• Eating the corpse of a floating eye (100% chance) or a (master) mind flayer (50%)
• Eating an amulet of ESP
• Polymorphing into a monster with telepathy (i.e., a floating eye or either mind flayer)
• Praying to your god under certain circumstances

Intrinsic telepathy can be lost if you are either hit by the gremlin's intrinsic-stealing attack at night, or else commit murder as a lawful or neutral character.

Extrinsic sources

Extrinsic telepathy can be acquired through the following methods:

• Wearing an amulet of ESP, including the Eye of the Aethiopica, or a helm of telepathy
• Carrying any of the following artifacts:
  • The Longbow of Diana
  • The Orb of Detection
  • The Magic Mirror of Merlin
  • The Platinum Yendorian Express Card

Strategy

Intrinsic telepathy is among the more useful methods of detecting monsters, although it cannot be used to spot mindless monsters - for this reason, it is best supplemented with other forms of monster detection, such as warning, in order to detect dangerous mindless monsters such as golems and green slimes.

Players very often keep a blindfold or towel on hand so they can blind and unblind at will to scan the level for specific monsters as necessary; telepathy also allows for much safer movement if blinded by other means, such as an exploding yellow light. As both forms of telepathy display monsters while blind, some players may mistake this as being exclusive to the intrinsic property.

The mental blasts of mind flayers can be counteracted if you have extrinsic telepathy by temporarily removing or stashing your source of telepathy; this is often unnecessary in practice, since the damage is usually negligible outside of scenarios involving early minesflayers or else escaping from other monsters while at low HP. See the article on mind flayers for other strategies dedicated to handling them in combat.

Origin

Telepathy is the ability to transmit information from one person's mind to another's without using any known human sensory channels or physical interaction. The term was first coined in 1882 by Frederic W. H. Myers, a founder of the Society for Psychical Research (SPR), and is among the more popular concepts of thought-reading; the concept emerged in the context of significant advances in physical sciences of the era, where scientific concepts were applied to mental phenomena in the hopes of understanding other events considered paranormal (i.e. beyond the understanding of science at that time). As the scientific disciplines progressed in development, telepath experiments have been criticized for a lack of proper controls and repeatability, and the topic is generally considered pseudoscience due to lack of good evidence.

ESP is an abbreviation for ExtraSensory Perception, which refers to any perception not gained through the body's physical senses. The term was coined by parapsychologist Joseph Banks Rhine in his 1934 book (also titled Extrasensory Perception), and encompasses a number of purported psychic abilities, including telepathy and clairvoyance, among others.

Messages

You feel a strange mental acuity.

You gained intrinsic telepathy from eating a corpse.

You feel in touch with the cosmos.

As above while hallucinating.

A wave of psychic energy pours over you! It locks onto your telepathy!

A (master) mind flayer is on the same level as you and attacking you via telepathy.

Variants

xNetHack

In xNetHack, gnomish wizards, kobold shamans, and orc shamans are telepathic, and may infrequently grant intrinsic telepathy when eaten.