The
difference is night and day. The kind of
chance with which most of us are familiar is not what we think it is. Indeed, if one knows all the factors
involved, chance events are not chance at all.
A simple
example involves a deck of shuffled cards.
When a standard deck of cards is thoroughly shuffled, we assume them to
be in random order. Trying to guess
which card is on top gives us a one chance in 52 of being correct.
But in fact,
if one were to very carefully watch the shuffling, and if one had the ability
to track each card during the process, then one could know exactly which card
ends up on top. Chance is not
involved.
It only
seems to be chance, because it is virtually impossible to keep track of the
cards as they are shuffled. Our
ignorance of where the cards are in the shuffled deck forces us to guess. But the cards are not in truly random
order. They are in what is called, pseudo-random
order, or fake-random order. Computer-generated
random numbers are actually the product of a pseudo-random algorithm. If one knows the algorithm and the seed
number, all the resulting numbers can be precisely predicted.
Even dice
rolls are not truly random. If one could
know all the factors involved, all the physical parameters, all the velocities
and angular momentum, the coefficients of friction, the air density—everything involved—then
the outcome of the dice roll is in principle predictable, not random.
The other
kind of randomness is truly random. It
applies in quantum physics. Even Albert
Einstein never accepted true randomness, but a century of experiments in
quantum physics (QM) leave no doubt that only the theory of true randomness can
explain QM.
In other
words, unlike with the shuffled deck, no amount of knowledge of the factors
involved can predict the outcome of quantum events, such as the spontaneous
decay of a radioactive atom.
It is as if,
after carefully watching the shuffling of a deck, the top card being known to
be red, could suddenly change to a black one with no physical force being
applied. True chance, pure probability
(within parameters) is the underlying reality.
Another way
of saying this is that in pseudo-randomness, nature knows what the top card
is. But in quantum physics, not even
nature knows when the spontaneous decay will occur in a radioactive atom.
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