🚀 go-pugleaf

Keith F. Lynch <KFL%MX.LCS.MIT.EDU@MC.LCS.MIT.EDU> writes:
> 
>    From: pyramid!decwrl!amdcad!lll-crg!hoptoad!tim@Ucb-Vax.arpa (Tim Maroney)
> 
>    ... biasing a random number generator, which is presumably a
>    microscopic silicon device whose functioning requires special
>    training for understanding.
> 
>  A true random number generator might be a speck of radium with a
>Geiger counter next to it.  A silicon device, i.e. computer, can only
>be a ~rpseudo-random number generator.  The numbers that are produced by
>it may be well distributed, but they only APPEAR random - because of
>our lack of knowledge of the algorithm or lack of ability to compute
>its results in our heads.  If someone appears to demonstrate an ability
>to bias a properly operating pseudo-random number generator, that is
>excellent evidence that the experiment IS bogus.

True random number generators are used in two ways in parapsychology. They
are used in PK experiments, where the subject is instructed to "try" to get
the generator to match a particular target or sequence of targets. They are
also used in precognition experiments where the subject attempts to guess
what the RNG will later generate. 

It is fairly clear that these "precognition" experiments could actually be
explained by PK.  Whether *all* apparent precognition can be explained in
terms of PK and/or clairvoyance is a matter of serious debate in
parapsychology.  Spontaneous case material is highly suggestive that
precognition as a distinct phenomena exists, but spontaneous case material,
because of intrinsically poor controls, can never be more than suggestive.
More elaborate experiments are also suggestive of "true" precognition" but
again, no more than that. 

Anyway, RNG's come in two basic designs.  Both base their randomness on a
random event generator (REG).  In the more common design, a high-speed
toggle flip-flop (for binary "numbers") or counter is driven by a clock
(generally in the MHz range).  The REG generates "events" at a relatively
low rate (hundredths of a second or slower).  When an event is registered
the clock is stopped and the counter is read as the result.  The other
design is in the sense the opposite.  A high-speed REG "toggles" a
flip-flop or counter over a fixed period of time.  When the time expires,
the counter is read for the result.  The time is set so that the average
number of events is several hundred or even thousand times the period of
the counter. 

There are two principal designs of REGs in use as well.  One, the Schmidt
REG, is basically the design mentioned by Keith: a radioactive source and a
Geiger counter. 

The other is, fundamentally, a "silicon device."  In particular it is a
reverse biased diode junction (usually a Zener diode).  This is
electronically noisy. The noise is amplified and passed through a threshold
switch.  The threshold is adjusted to produce the desired rate of events.
The nature of the noise in semiconductor junctions is an open issue
currently under investigation.  The two major sources are thermal noise
(which is what it sounds like) and "1/f noise" (which is a rough
description of its spectrum). The current theories on both of these sources
seem to agree that they both are quantum mechanically non-deterministic,
i.e., that their behavior is dominated by effects at the quantum level. 

A third design for a REG is sometimes used for convenience but is
considered much less rigorous.  A human operator hits a button which stops
a clock. The accuracy needed to "control" this situation is measured in
milli- or microseconds, which is thought to be much smaller than the
capabilities of the human nervous system.  The random variability used here
is that of the nervous system.  This is usually used in the form of hitting
a keyboard key which causes the low order bit(s) of the system clock to be
read on a computer.  This has the advantage of requiring no special
equipment but raises a host of issues as to its reliability, theoretical
correctness and interpretation. 

Pseudo-random number generators (PRNGs) *are* used in parapsychology;
either by themselves in clairvoyance experiments or with true REGs in PK
and precognition experiments.  I have never heard of a case in which a
pseudo-random sequence was claimed to have been "tampered with" via PK. 

The seed for a PRNG is always the result, however, of a mechanical process
and there is strong evidence that its selection may be influenced by
unconscious psi (whatever that is).  The accepted practice in clairvoyance
experiments is therefore to use a single very-long sequence for all
experiments at a particular lab over an indefinite time period. 

		Topher Cooper

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Disclaimer:  This contains my own opinions, and I am solely responsible for
them.