In parapsychology, precognition (from the Latin præ-, “before,” + cognitio, “acquiring knowledge”), also called future sight, and second sight, is a type of extrasensory perception that would involve the acquisition or effect of future information that cannot be deduced from presently available and normally acquired sense-based information or laws of physics and/or nature. A premonition (from the Latin praemonēre) and a presentiment are information about future events that is perceived as emotion.
The existence of precognition, as with other forms of extrasensory perception, is not accepted as other than a purely psychological process by the mainstream scientific community because no replicable demonstration, "on demand", has ever been achieved.
Scientific investigation of extrasensory perception (ESP) is complicated by the definition which implies that the phenomena go against established principles of science. Specifically, precognition would violate the principle that an effect cannot occur before its cause. However, there are established biases, affecting human memory and judgment of probability, that create convincing but false impressions of precognition.