rmiller wrote:
>At 03:58 PM 6/6/2005, you wrote:
>>rmiller wrote:
>>
>>>At 03:01 PM 6/6/2005, Pete Carlton wrote:
>>>
>>>>(snip)
>>>>
>>>>The point is, there are enough stories published in any year that it
>>>>would be a trivial matter to find a few superficial resemblances between
>>>>any event and a story that came before it.
>>>
>>>Let's look a little closer at the story in terms of gestalts.
>>>
>>>On one side we have published author Robert Heinlein writing a story in
>>>1939 about a guy named Silard who works with a uranium bomb, a beryllium
>>>target and a fellow named "lenz." We'll leave Korzybski out of this one
>>>(I suspect Heinlein borrowed the name from A. Korzybski, a sematicist of
>>>some renown back in the 1930s.) To me the interesting nodes involve the
>>>words "Silard" "lenz" "beryllium," "uranium" and "bomb." So let's agree
>>>that here is a story that includes a gestalt of the words "Silard, lenz,
>>>beryllium, uranium and bomb."
>>
>>But you can't use that particular "gestalt" when talking about the
>>probability that a coincidence like this would occur, because you never
>>would have predicted that precise gestalt in advance even if you were
>>specifically looking for stories that anticipated aspects of the Manhatten
>>project.
>
>Where on earth did *that* gestalt rule come from??? ;-)
It comes from the idea that if you are going to claim a "hit" for ESP or
whatever that has a significance level of 1 in 10^9, then it should be true
that *if* ESP didn't exist and the hit was a pure coincidence, then no more
than 1 in 10^9 versions of you in different possible universes should be
claiming to have seen a hit with that level of significance--that seems to
be inherent in the meaning of "significance level", no? If 1 out of 15
parallel versions of you would end up claiming to see a hit with a
significance level of 1 in 10^9, *even if there was no ESP and these hits
were pure coincidence*, then obviously something is wrong with the reasoning
that these various versions of you are using. Do you disagree?
I wrote:
>
>> It would make more sense to look at the probability of a story that
>>includes *any* combination of words that somehow anticipate aspects of the
>>Manhatten project. Let's say there were about 10^10 possible such gestalts
>>we could come up with, and if you scanned trillions of parallel universes
>>you'd see the proportion of universes where a story echoed at least one
>>such gestalt was fairly high--1 in 15, say.
>
>
>
>>This means that in 1 in 15 universes, there will be a person like you who
>>notices this anticipation and, if he uses your method of only estimating
>>the probability of that *particular* gestalt, will say "there's only a 1
>>in 10^9 probability that something like this could have happened by
>>chance!" Obviously something is wrong with any logic that leads you to see
>>a 1 in 10^9 probability coincidence happening in 1 in 15 possible
>>universes, and in this hypothetical example it's clear the problem is that
>>these parallel coincidence-spotters are using too narrow a notion of
>>"something like this", one which is too much biased by hindsight knowledge
>>of what actually happened in their universe, rather than something they
>>plausibly might have specifically thought to look for before they actually
>>knew about the existence of such a story.
>>
you responded:
>>Sounds like you're invoking rules of causation here--post hoc rather than
>>ad hoc, hindsight bias, etc. Certainly I am not suggesting Heinlein's
>>story caused Szilard to be hired (interesting thought, though!) And
>>unless I want to invoke Cramer's transactional approach, I would not
>>really want to think that the Manhattan Project caused Heinlein to write
>>his story. That would require reverse causation, and we know that doesn't
>>happen. This is very simple: we have instances in which Heinlein includes
>>key words (definable as being essential to the story---without them,
>>different story) that form a gestalt of. . .well, key words. These words
>>are equivalent to those describing the Manhattan Project and not many
>>other things. To show that there are not many other things these key word
>>gestalts describe, one can wait a year and use Google Print to call up all
>>the books and stories associated with these key words. Then we will have
>>a probability to work with. Since the gestalts are separated by four
>>years (or thereabouts) then we shouldn't have to invoke causation.
>
You are misunderstanding the meaning of "hindsight bias", it's not about the
prediction causing the event being predicted or vice versa, it's about *you*
making a retroactive calculation of the "probability" of a particular
successful prediction which is illegitimate because you incorporate
knowledge of what already happened into your choice of the "target" whose
probability of predicting you want to calculate. This is illustrated by an
anecdote involving Richard Feynman which is quoted at
http://www.numeraire.com/value_wizard/probable.htm :
What came to Feynman by "common sense" were often brilliant twists that
perfectly captured the essence of his point. Once, during a public lecture,
he was trying to explain why one must not verify an idea using the same data
that suggested the idea in the first place. Seeming to wander off the
subject, Feynman began talking about license plates. "You know, the most
amazing thing happened to me tonight. I was coming here, on the way to the
lecture, and I came in through the parking lot. And you won't believe what
happened. I saw a car with the license plate ARW 357. Can you imagine? Of
all the millions of license plates in the state, what was the chance that I
would see that particular one tonight? Amazing!" A point that even many
scientists fail to grasp was made clear through Feynman's remarkable "common
sense."
Of course in this example Feynman did not anticipate in advance what licence
plate he'd see, but the kind of "hindsight bias" you are engaging in can be
shown with another example. Suppose you pick 100 random words out of a
dictionary, and then notice that the list contains the words "sun", "also",
and "rises"...as it so happens, that particular 3-word "gestalt" is also
part of the title of a famous book, "the sun also rises" by Hemingway. Is
this evidence that Hemingway was able to anticipate the results of your
word-selection through ESP? Would it be fair to test for ESP by calculating
the probability that someone would title a book with the exact 3-word
gestalt "sun, also, rises"? No, because this would be tailoring the choice
of gestalt to Hemingway's book in order to make it seem more unlikely, in
fact there are 970,200 possible 3-word gestalts you could pick out of a list
of 100 possible words, so the probability that a book published earlier
would contain *any* of these gestalts is a lot higher than the probability
it would contain the precise gestalt "sun, also, rises". Selecting a precise
target gestalt on the basis of the fact that you already know there's a
book/story containing that gestalt is an example of hindsight bias--in the
Heinlein example, you wouldn't have chosen the precise gestalt of
Szilard/lens/beryllium/uranium/bomb from a long list of words associated
with the Manhattan Project if you didn't already know about Heinlein's
story.
Jesse
Received on Tue Jun 07 2005 - 15:47:20 PDT