The senses are the media through which stimuli in the environment of an organism act on it (external senses); also, the internal senses which report on the internal state of the organism (through thirst and hunger, pain, etc). The organs of sense, the eye, ear, skin, etc., all contain specialized cells and nerve endings which communicate with centers in the nervous system. Sense organs my be stimulated by pressure (in touch, hearing, and balance), chemical stimulation (smell and taste), or electromagnetic radiation (vision; heat sensors).
Extrasensory perception (ESP) is the purported sensation other than by the recognized senses of an event or object; and, by extension, those powers of the mind (such as telekinesis, the moving of distant objects by the exercise of willpower) that has to far eluded scientific evaluation. The best known and most researched area of ESP is telepathy, the supposed ability of two or more individuals to communicate without sensory contact: though laboratory tests have been inconclusive and generally negative (see telepathic species). Analogous is empathy, the communication across distance of emotion. Another hypothesized aspect of ESP is precognition, the prior knowledge of an event: again, laboratory tests have been inconclusive.