Rebuttal : Lincoln and Kennedy: Bound by coincidence 

Aparthib Zaman.

In response to : http://groups.yahoo.com/group/mukto-mona/message/5021 

I would like to discuss some generalities relating to coincidences and "strange connections" that would apply to all coincidences, not just "Kennedy's and Lincoln's strange connection" that Shayon's post referred to. I must admit that Shayon only presented some interesting facts of coincidences (Although some of those "facts" may be distorted as Avijit's research has shown) not drawn any conclusions from it. My discussion is general and applies to those who may "see" some divine connection in those coincidences.
 
The desire to see divine connections or design in mundane occurrences of coincidences is a strong human instinct arising out of a yearning for a world beyond this observable one and rooted in the desire for life after death in order to find a meaning of this life and to move on. This yearning was behind Jung's theory of Synchronicity, which is nothing but a pseudo-scientific mish-mash, although in his desperation he even tried to enlist some help from his friends well-versed in Quantum Physics. He tried to link an aspect of Quantum Mechanics called Quantum non-locality (Einstein called it spooky) with apparent connections between human experiences. A case of pure quackery like astrology. Quantum non-locality has many alternate scientific explanations and is not "spooky" anymore, although it still remains the ultimate epistemological intellectual challenge to physicists.
 
Anyway, the fact is that all coincidences appear to be strange connections to many because of
(a) improper understanding of statistics
(b)
selective bias of human mind
, and
(c)
sometimes due to succumbing to intentional manipulations of facts.

Misunderstanding of statistics can lead one to view a not-so-unlikely occurrence as very unlikely. Selective bias leads one to forget and ignore the majority of events, all of which are individually very unlikely, not treat them as coincidences or strange connections but only the ones that appear to be interesting to the human mind.
 
For example, if we roll ten dice the likelihood of getting the sequence 6526553214 is the same as 6666666666 both of which are equally likely and also very unlikely to occur in one trial.
(1/6x1/6x1/6x1/6x1/6x1/6x1/6x1/6x1/6x1/6) But the former will not catch anyone's attention, the latter will.
 
When one is dealt a bridge hand of thirteen cards, the probability of being dealt that particular hand is less than one in 600 billion. Still, it would be absurd for someone to be dealt a hand, examine it carefully, calculate that the probability of getting it is less than one in 600 billion, and then conclude that he must not have been dealt that very hand because it is so very improbable or that it must be a divine connection for him to get this rare hand!
 
Another important aspect of probability that is not appreciated by many is that time and numbers play a very important role in statistics. A very unlikely event will eventually occur given enough time. Or, equivalently, if many trials are conducted for an unlikely event simultaneously, one of the trials will materialize the very unlikely. Those who have studied statistical Physics will recognize this in the Ergodic Hypothesis, a very important concept. Sometimes we are amazed that out the billions of known stars and their planets only Sun harbours wonderful life forms and only on the planet earth. Is that a surprise? Life requires a sensitive range of conditions of temperature, gravity, density of atmosphere, right distance from star, right tilt of the axis, etc., for life to evolve. Only earth satisifes this condition. Its like 6X6X6X6X6X6X6X6X6X6 people rolling ten dice at once. One of them will certainly roll 6666666666. Any surprise? All the billions of planets are like ten rolled dice. Only one (earth) is 666666666 (i.e., has conditions suitable for life forms). So here we are, on planet earth wondering about life. If planet "X", instead, satisfied the conditions of life instead of earth then we would be on planet "X". But then we would call "X" earth. It's only a matter of label.
 
How about the lottery? One lucky person picks the right number. Someone has to win it if all the numbers are sold out. No divine connection. Yet the winning person may view it as a divine connection for him to win it. Even if that lucky person has just lost his home and belongings in a fire that would not make it any more divine. Because again if anything can happen at all, it will eventually happen, if one waited long enough. No one who has lost his belongings in fire has ever won in a lottery before, in million years of human history, humanity waited long enough for it to happen and finally it did happen to Mr. X on day Y of Year Z. By the same logic a billionaire may also someday win a lottery ticket (Talking about carrying coal to Newcastle!) it would not have any different significance from the former case. No amount of coincidences of PHYSICALLY POSSIBLE (i.e., natural) events can point to divine or supernatural connections. Occam's Razor will always point to a natural explanation through an eventual realization of a very unlikely (but not impossible) event.
 
A nuts and bolts calcualtion may help dispel the mystic of strange coincidences that we sometimes experience in life (Like you were thinking of an old friend in an airport and then suddenly he appears, approaching you). A person may have 100 distinct experiences a day. In ten years, for 1000 people
that would mean 4950x3650x1000=18,06750000 pairs of events. So its very likely that some of those events will be of strange coincidence types to some of those 1000 persons.
 
As a final example, let's take the case of "prophetic" dreams.  Sometimes a person "X" dreams of an event and the event takes place soon after the dream.  X sees a divine connection in his dream. Now, consider this. Normal people have about 25 dreams/night. With 250 million people in US there must be billions of dreams dreamt everynight and trillions in a year.  With so many dreams, some are bound to match with reality and seem prophetic. It would be astonishing if there wasn't any (p-55 Schick).
 
Some may object that the connections do not have to be divine. They could be natural, but not mere chances. There must be some deep natural (scientific) connections between them. This is what Jung had hinted at. But that is a mere "May be". A natural or scientific connection can only be made through scientific method itself. And science has not found any connections between such coincidences. Nor is there any need to.  All such connections have been explained nicely through Occam's Razor by probability theory, which is an important tool of science as well.
 
I hope to have dispelled some myth and misconceptions about coincidences. I apologize if I seemed to have ruined any hope for divine supernatural connection that certainly appears to be a more appealing option. And one can continue to believe in that. After all, placebos are as effective (or more) a therapy as real drugs. But if it did inspire a little bit of interest in critcial thinking then I suggest going further and read the following two books.
 
1.  How to Think of Weird Things - Theodore Schick & Lewis Vaugn

2.  Innumeracy: Mathematical Illiteracy and its Consequences - John Allen Paulos. 
 
Thanks.

Aparthib