Postdiction
Encyclopedia
According to critics of paranormal
beliefs, postdiction (or post-shadowing, retroactive clairvoyance, or prediction after the fact) is an effect of hindsight bias
that explains claimed predictions of significant events, such as plane crashes and natural disasters. In religious contexts it is frequently referred to by the Latin term vaticinium ex eventu, or foretelling after the event. Through this term, critics point out the fact that many biblical prophecies (and similar prophecies in other religions) that may appear to have come true were in fact written after the events supposedly predicted, or that their text or interpretation were modified after the event to fit the facts as they occurred.
Skeptics of premonition use these terms in response to claims made by psychic
s, astrologers
and other paranormalists to have predicted an event, when the original prediction was vague, catch-all, or otherwise non-obvious.
Most predictions from such figures as Nostradamus
and James Van Praagh
are written with such seemingly deliberate vagueness and ambiguity as to make interpretation nearly impossible before the event, rendering them useless as predictive tools. After the event has occurred, however, details are shoehorned
into the prediction by the psychics or their supporters using selective thinking — emphasize the "hits", ignore the "misses" — in order to lend credence to the prophecy and give the impression of an accurate "prediction". Inaccurate predictions are omitted.
Supporters sometimes contend that the problem lies not with the wording of the prediction, but with the interpretation — an argument sometimes used by supporters of religious texts. This argument may lead to the question: "What is the point of a prediction that cannot be interpreted correctly before the event?" However, the argument is not that the prediction could not have been interpreted correctly prior to the event, but simply that it was not in the case in question, thus the question is working from a false premise
. Of course, any "prediction" that is so vague as to not be correctly interpreted before the event it allegedly "predicted" is functionally equivalent to no prediction at all.
Vague: The prediction makes a non-specific claim. For example, it predicts a "disaster" of some kind but not what it is. Such a prediction can be massaged to fit any number of events. Likewise, a prediction that does not state dates or places, or allows itself a large window of possible dates can be made to fit many possibilities. A prophecy attributed to Saint Malachy
(but widely regarded as a 16th century forgery
) claims to predict the succession of Popes
by describing each one briefly. However, each description is sufficiently vague that it can be massaged to fit after the fact.
Open ended: The prediction has a very long cut-off date or none at all and therefore runs indefinitely. Many of Nostradamus
' quatrains are open-ended and have been postdicted over the centuries to fit various contemporary events.
Recycled: The prediction is reused again and again in order to match the most recent event. Nostradamus' quatrains have been recycled numerous times.
Catch-all: The prediction covers more than one possible outcome. For example, the Delphi
c Oracle
's answer as to whether Croesus
should attack the Persians: If you attack you will destroy a mighty empire. Croesus
attacked, destroying his own empire.
Shotgunning: The prediction is in fact many predictions, designed to cover a range of events and claim credit even if only one of them happens. For example, claiming that a particular date is "unlucky" and then citing a dozen or so things that might happen on it. See selective thinking
.
Statistically likely: The prediction makes a claim for something that happens with enough frequency that a high hit rate is virtually assured. For example, predicting terrorism on any day of the year, or particularly around national holidays, anniversaries (or similar events), or religious festivals.
Unfalsifiable: The prediction makes a claim that is impossible to verify or falsify
. For example, a belief arose amongst a few in 2003 that a "Planet X
" would pass the Earth in May of that year. When it singularly failed to appear they claimed it was shrouded so that only an "educated eye" could see it and various other excuses, while discounting the most obvious reason — that Planet X does not exist at all in the form predicted.
Unavailable until after the fact: A prediction cannot be verified if there is no public record of when it was made. A famous example was the psychic Tamara Rand, who "predicted" that Ronald Reagan
was in danger of someone with the initials "J.H."
. The video interview in which this prediction was made was shot the day after the assassination attempt.
Counting the hits and not the misses: The prediction may be part of a series, but is singled out because it can be favourably interpreted, even if the series itself follows the laws of probability. For example, the prediction might correctly state movement on the stock market when previous or subsequent predictions have been wrong.
Allegory: The postdiction resorts to tenuous allegorical explanations to turn literal misses into hits. For example the postdiction might explain that a famous person has suffered a "spiritual" death to explain why they are still walking around despite a prediction that says otherwise.
Moving the goalposts: The event must be "shoehorned" to fit the prediction because it differs in some significant way. For example, the prediction predicts an earthquake on one day when in fact it happens on a different day. Once again, Nostradamus
supporters occasionally use this technique, as Nostradamus supposedly predicted the founding of the Institut Pasteur in 1888 (it was actually a year later) and the September 11 terrorist attacks
on the 45th parallel(actually significantly southwards).
These types are not exclusive, so a prediction could be vague, statistically likely and open-ended at the same time.
and Sejnowski, 2000).
Paranormal
Paranormal is a general term that designates experiences that lie outside "the range of normal experience or scientific explanation" or that indicates phenomena understood to be outside of science's current ability to explain or measure...
beliefs, postdiction (or post-shadowing, retroactive clairvoyance, or prediction after the fact) is an effect of hindsight bias
Hindsight bias
Hindsight bias, or alternatively the knew-it-all-along effect and creeping determinism, is the inclination to see events that have already occurred as being more predictable than they were before they took place. It is a multifaceted phenomenon that can affect different stages of designs,...
that explains claimed predictions of significant events, such as plane crashes and natural disasters. In religious contexts it is frequently referred to by the Latin term vaticinium ex eventu, or foretelling after the event. Through this term, critics point out the fact that many biblical prophecies (and similar prophecies in other religions) that may appear to have come true were in fact written after the events supposedly predicted, or that their text or interpretation were modified after the event to fit the facts as they occurred.
Skeptics of premonition use these terms in response to claims made by psychic
Psychic
A psychic is a person who professes an ability to perceive information hidden from the normal senses through extrasensory perception , or is said by others to have such abilities. It is also used to describe theatrical performers who use techniques such as prestidigitation, cold reading, and hot...
s, astrologers
Astrology
Astrology consists of a number of belief systems which hold that there is a relationship between astronomical phenomena and events in the human world...
and other paranormalists to have predicted an event, when the original prediction was vague, catch-all, or otherwise non-obvious.
Most predictions from such figures as Nostradamus
Nostradamus
Michel de Nostredame , usually Latinised to Nostradamus, was a French apothecary and reputed seer who published collections of prophecies that have since become famous worldwide. He is best known for his book Les Propheties , the first edition of which appeared in 1555...
and James Van Praagh
James Van Praagh
James Van Praagh is a self-proclaimed medium who has written several books on spirituality and spirit communication.-Early life and career:Van Praagh was born in Bayside, New York and is the youngest of four children...
are written with such seemingly deliberate vagueness and ambiguity as to make interpretation nearly impossible before the event, rendering them useless as predictive tools. After the event has occurred, however, details are shoehorned
Shoehorning
Shoehorning is a ploy used by psychics, or religious apologetic or other charlatans, as a way to make it sound like their prophecies or those of earlier prophets had come true. The word is derived from shoehorn, a smooth curved implement, often of plastic or metal, inserted at the heel to help put...
into the prediction by the psychics or their supporters using selective thinking — emphasize the "hits", ignore the "misses" — in order to lend credence to the prophecy and give the impression of an accurate "prediction". Inaccurate predictions are omitted.
Supporters sometimes contend that the problem lies not with the wording of the prediction, but with the interpretation — an argument sometimes used by supporters of religious texts. This argument may lead to the question: "What is the point of a prediction that cannot be interpreted correctly before the event?" However, the argument is not that the prediction could not have been interpreted correctly prior to the event, but simply that it was not in the case in question, thus the question is working from a false premise
False premise
A false premise is an incorrect proposition that forms the basis of a logical syllogism. Since the premise is not correct, the conclusion drawn may be in error...
. Of course, any "prediction" that is so vague as to not be correctly interpreted before the event it allegedly "predicted" is functionally equivalent to no prediction at all.
Types
Accusations of postdiction might be applicable if the prediction was:Vague: The prediction makes a non-specific claim. For example, it predicts a "disaster" of some kind but not what it is. Such a prediction can be massaged to fit any number of events. Likewise, a prediction that does not state dates or places, or allows itself a large window of possible dates can be made to fit many possibilities. A prophecy attributed to Saint Malachy
Saint Malachy
Saint Malachy was the Archbishop of Armagh, to whom were attributed several miracles and a vision of the identity of the last 112 Popes...
(but widely regarded as a 16th century forgery
Forgery
Forgery is the process of making, adapting, or imitating objects, statistics, or documents with the intent to deceive. Copies, studio replicas, and reproductions are not considered forgeries, though they may later become forgeries through knowing and willful misrepresentations. Forging money or...
) claims to predict the succession of Popes
Prophecy of the Popes
The Prophecy of the Popes, attributed to Saint Malachy, is a list of 112 short phrases in Latin. They purport to describe each of the Roman Catholic popes , beginning with Pope Celestine II and concluding with the successor of current pope Benedict XVI, a pope described in the prophecy as "Peter...
by describing each one briefly. However, each description is sufficiently vague that it can be massaged to fit after the fact.
Open ended: The prediction has a very long cut-off date or none at all and therefore runs indefinitely. Many of Nostradamus
Nostradamus
Michel de Nostredame , usually Latinised to Nostradamus, was a French apothecary and reputed seer who published collections of prophecies that have since become famous worldwide. He is best known for his book Les Propheties , the first edition of which appeared in 1555...
' quatrains are open-ended and have been postdicted over the centuries to fit various contemporary events.
Recycled: The prediction is reused again and again in order to match the most recent event. Nostradamus' quatrains have been recycled numerous times.
Catch-all: The prediction covers more than one possible outcome. For example, the Delphi
Delphi
Delphi is both an archaeological site and a modern town in Greece on the south-western spur of Mount Parnassus in the valley of Phocis.In Greek mythology, Delphi was the site of the Delphic oracle, the most important oracle in the classical Greek world, and a major site for the worship of the god...
c Oracle
Oracle
In Classical Antiquity, an oracle was a person or agency considered to be a source of wise counsel or prophetic predictions or precognition of the future, inspired by the gods. As such it is a form of divination....
's answer as to whether Croesus
Croesus
Croesus was the king of Lydia from 560 to 547 BC until his defeat by the Persians. The fall of Croesus made a profound impact on the Hellenes, providing a fixed point in their calendar. "By the fifth century at least," J.A.S...
should attack the Persians: If you attack you will destroy a mighty empire. Croesus
Croesus
Croesus was the king of Lydia from 560 to 547 BC until his defeat by the Persians. The fall of Croesus made a profound impact on the Hellenes, providing a fixed point in their calendar. "By the fifth century at least," J.A.S...
attacked, destroying his own empire.
Shotgunning: The prediction is in fact many predictions, designed to cover a range of events and claim credit even if only one of them happens. For example, claiming that a particular date is "unlucky" and then citing a dozen or so things that might happen on it. See selective thinking
Confirmation bias
Confirmation bias is a tendency for people to favor information that confirms their preconceptions or hypotheses regardless of whether the information is true.David Perkins, a geneticist, coined the term "myside bias" referring to a preference for "my" side of an issue...
.
Statistically likely: The prediction makes a claim for something that happens with enough frequency that a high hit rate is virtually assured. For example, predicting terrorism on any day of the year, or particularly around national holidays, anniversaries (or similar events), or religious festivals.
Unfalsifiable: The prediction makes a claim that is impossible to verify or falsify
Falsifiability
Falsifiability or refutability of an assertion, hypothesis or theory is the logical possibility that it can be contradicted by an observation or the outcome of a physical experiment...
. For example, a belief arose amongst a few in 2003 that a "Planet X
Planet X
Following the discovery of the planet Neptune in 1846, there was considerable speculation that another planet might exist beyond its orbit. The search began in the mid-19th century but culminated at the start of the 20th with Percival Lowell's quest for Planet X...
" would pass the Earth in May of that year. When it singularly failed to appear they claimed it was shrouded so that only an "educated eye" could see it and various other excuses, while discounting the most obvious reason — that Planet X does not exist at all in the form predicted.
Unavailable until after the fact: A prediction cannot be verified if there is no public record of when it was made. A famous example was the psychic Tamara Rand, who "predicted" that Ronald Reagan
Ronald Reagan
Ronald Wilson Reagan was the 40th President of the United States , the 33rd Governor of California and, prior to that, a radio, film and television actor....
was in danger of someone with the initials "J.H."
John Hinckley, Jr.
John Warnock Hinckley, Jr., attempted to assassinate U.S. President Ronald Reagan in Washington, D.C., on March 30, 1981, as the culmination of an effort to impress teen actress Jodie Foster. He was found not guilty by reason of insanity and has remained under institutional psychiatric care since...
. The video interview in which this prediction was made was shot the day after the assassination attempt.
Counting the hits and not the misses: The prediction may be part of a series, but is singled out because it can be favourably interpreted, even if the series itself follows the laws of probability. For example, the prediction might correctly state movement on the stock market when previous or subsequent predictions have been wrong.
Allegory: The postdiction resorts to tenuous allegorical explanations to turn literal misses into hits. For example the postdiction might explain that a famous person has suffered a "spiritual" death to explain why they are still walking around despite a prediction that says otherwise.
Moving the goalposts: The event must be "shoehorned" to fit the prediction because it differs in some significant way. For example, the prediction predicts an earthquake on one day when in fact it happens on a different day. Once again, Nostradamus
Nostradamus
Michel de Nostredame , usually Latinised to Nostradamus, was a French apothecary and reputed seer who published collections of prophecies that have since become famous worldwide. He is best known for his book Les Propheties , the first edition of which appeared in 1555...
supporters occasionally use this technique, as Nostradamus supposedly predicted the founding of the Institut Pasteur in 1888 (it was actually a year later) and the September 11 terrorist attacks
September 11, 2001 attacks
The September 11 attacks The September 11 attacks The September 11 attacks (also referred to as September 11, September 11th or 9/119/11 is pronounced "nine eleven". The slash is not part of the pronunciation...
on the 45th parallel(actually significantly southwards).
These types are not exclusive, so a prediction could be vague, statistically likely and open-ended at the same time.
In neuroscience
In the field of neuroscience, postdiction has a different meaning: here it indicates that the brain collects up information after an event before it retrospectively decides what happened at the time of the event (EaglemanDavid Eagleman
David Eagleman is a neuroscientist at Baylor College of Medicine, where he directs the Laboratory for Perception and Action and the Initiative on Neuroscience and Law. He is best known for his work on time perception, synesthesia, and neurolaw...
and Sejnowski, 2000).
See also
- ClairvoyanceClairvoyanceThe term clairvoyance is used to refer to the ability to gain information about an object, person, location or physical event through means other than the known human senses, a form of extra-sensory perception...
- DivinationDivinationDivination is the attempt to gain insight into a question or situation by way of an occultic standardized process or ritual...
- Forer effectForer effectThe Forer effect is the observation that individuals will give high accuracy ratings to descriptions of their personality that supposedly are tailored specifically for them, but are in fact vague and general enough to apply to a wide range of people...
- Fortune-tellingFortune-tellingFortune-telling is the practice of predicting information about a person's life. The scope of fortune-telling is in principle identical with the practice of divination...
- Hindsight biasHindsight biasHindsight bias, or alternatively the knew-it-all-along effect and creeping determinism, is the inclination to see events that have already occurred as being more predictable than they were before they took place. It is a multifaceted phenomenon that can affect different stages of designs,...
- Magical thinkingMagical thinkingMagical thinking is causal reasoning that looks for correlation between acts or utterances and certain events. In religion, folk religion, and superstition, the correlation posited is between religious ritual, such as prayer, sacrifice, or the observance of a taboo, and an expected benefit or...
- Retroactive continuity
- Texas sharpshooter fallacyTexas sharpshooter fallacyThe Texas sharpshooter fallacy is a logical fallacy in which pieces of information that have no relationship to one another are called out for their similarities, and that similarity is used for claiming the existence of a pattern. This fallacy is the philosophical/rhetorical application of the...