The more astonishing a coincidence is, the more it deserves scrutiny.
Some coincidences are extraordinarily amazing like the series of serendipities that led to the discovery and manufacturing of penicillin (Beitman, p. 140-2). Some are trivial (like thinking of a strange word and a little later seeing or hearing that word).
Why judge the quality of coincidences?
The higher its quality, the more likely the coincidence offers useful information, so the more reason to examine it. (Although this statement seems plausible, we need to test it out.)
The primary variables that contribute to the quality of coincidences include probability, impact and explanation requiring a possibly new scientific finding. Secondary variables include the degree of similarity of the coincidence elements, pattern weirdness and the breadth of the time window for the appearance of the second element.
(Please note: there will be exceptions to most if not all the generalizations made in the following two sections, because coincidence study is in its early phase.)
The primary variables that influence quality
Probability: the lower the probability, the higher the quality. Context is an important variable in determining probability. Context includes both Intrapersonal and situational variables.
Coincidence Sensitivity: The more sensitive people are to coincidences, the higher the probability of their experiencing a coincidence because coincidence sensitive people see more coincidences.
Situational variables: During times of transition, high emotion and need coincidences are more likely to be occur. These situations increase the probability of a coincidence.
Impact: the higher the impact, the higher the quality. Impact takes two forms: subjective and objective.
Subjective impact is the degree of emotional intensity (surprise, amazement, so what) and the coincider’s intuitive reading of the value of the coincidence as well as how strongly the coincidence confirms the coincider's own explanatory bias. Explanations include: probability, psychodynamics and God-Universe-Mystery. Developing a Likert continuum scale (major to minor impact) would be useful here.
Objective impact refers to the practical effect on the coincider’s life which may involve decision making, personal psychology, relationships, work, health, money, ideas, and spirituality. Having another person rate the impact would start with another continuum scale (mild, average, strong and extreme).
Explanation: Some coincidences suggest explanations beyond these usual ones. When the coincidence provides evidence for new scientific principles like telepathy, then coincidence quality increases.
The secondary variables that influence quality
Similarity: The elements of a coincidence may be exactly the same—like the same number showing up twice in significant ways.
More often the elements are similar, not exactly the same. The degree of similarity is influenced by both subjective and objective factors. Subjectively, some coinciders will stretch the similarities and diminish the differences to create a desired match between the elements. To an external observer, the coincider’s similarity rating may be hard to accept because the coincider wants to make the patterns similar. For example, Fred has not heard from Amy for several months. He is longing to be reunited with her. He starts singing her favorite song, “In my life” by the Beatles. A little later he turns on his car radio and hears “Sympathy for the devil” by the Rolling Stones. He says to himself, “The Stones came around the same time as the Beatles. Both bands are from England. I take that as a sign that she is still interested in me.” He tells his friend Tom who says, “That's a stretch! You are just looking for hope. You are ignoring the differences: the feelings of the songs were opposites (loving vs sinister), and the two bands were highly competitive.”
The greater the similarity, the higher the quality.
Computer programs for estimating similarity will provide some objective measures.
Pattern Weirdness: Quality increases with the rarity, oddness, or weirdness of the first element. The more unique the first pattern, the more difficult it is to find a match. Quality increases in parallel with the degree of pattern weirdness. For example, Stephen Jenkins was studying the biblical Zechariah’s vision of the four horsemen with their four horses of red, black, dapple and white. On August 23, 1973, out on a hotel’s balcony, he saw four horses quietly grazing: red, black, dapple and white. On July 23, 1974, out in the country with a group of school children, he saw a group of four ponies: red, black, dapple and white. (Roderick Main, p. 11-12.) That is a weird pattern being repeated!
Time Windows: The wider the time window, the higher the probability for a match and the lower the quality. This is because the more time passes, the more opportunities there are for a match.
How to rate quality
The first rating should come from the coincider’s intuition—the felt sense of importance.
Intuitions need to be honed. Objective measures can help in the honing process. First estimate the probability of the coincidence itself. Then assess it with the other quality criteria—degree of similarity, the breadth of the time window, et cetera. If the quality is high enough, look for usefulness and explanations.
Quality is ideally rated by both the coincider and an outside observer.
These quality categories are somewhat interdependent. Because this is the first attempt at systematically addressing the quality of coincidences, the principles and mathematics of this interdependence must wait for future developments.
Note: This analysis involves mind-thing coincidences in which a mental event matches an external event. It does not include thing-thing coincidences which involve a series of two or more elements that can be directly observed.
Addendum: And here is a 2012 scale for measuring the strength of a synchronicity.
Co-authored by Tara MacIsaac, a reporter for the Epoch Times and editor for the Beyond Science section. She explores the new frontiers of science, delving into ideas that could help uncover the mysteries of our wondrous world.