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 Provocations
Michael
LaBossiere
Number
Thirteen: Chance
Matters
of chance, such as the roll of a die, are such a common part of
life that almost everyone believes in random chance. Despite being
widespread, this belief is not justified. This will be shown by
drawing an analogy with David Hume's classic discussion of causation.
Before
exposure to philosophy, most people believe in causation. Seeing
a billiard ball striking and apparently moving another ball, we
think we witnessed causation. But, we do not observe causation.
All we observe is event X followed by event Y. According to Hume,
if we observe enough instances of X following Y we begin to expect
that X will always follow Y (think of Pavlov's Dog). However, regardless
of the number of observations, we are not justified in our belief.
When we say that X causes Y, we are reporting a psychological claim
that we expect Y when we observe X. A similar case can be made for
chance,
As
with causation, most people believe in chance. We see dice roll
and think the result will be a matter of chance. We do not, however,
see chance - we just see the die roll and land. There seem to be
two "reasons" for believing that chance is involved.
First,
we tend to attribute chance to matters that are unpredictable. For
example, when a die is rolled we know some number between one and
six will result, but we do not know which. Because we cannot predict
the outcome, we come to believe that chance must be involved.
While
this helps explain the psychology of the belief, there are many
things that are unpredictable that are not matters of chance. For
example, the effects of mixing two new chemicals together might
be unpredictable (we won't know until we try), yet not a matter
of chance. Saying that something is unpredictable simply reports
our ignorance - it does not reveal the nature of chance.
A
second way of looking at chance is to take something to be a matter
of chance if things could have turned out differently. The rolling
of a die seems to be an example of this. Though we rolled a three,
we could have rolled a six. Having seen sixes rolled before, we
come to believe things could have been different and thus believe
that chance was involved. However, chance seems to be more than
the possibility that things could have been different. After all,
things could turn out differently in non-chance situations. For
example, though we placed five kilograms of wheat on a scale we
could have placed ten kilograms. However, this would not be a matter
of chance. Thus, chance seems to involve something more.
This
something more seems to be that things could have been different,
even if everything was identical to the original event. For example,
suppose a person rolled a three on a die. If the situation were
recreated perfectly and a six were rolled, then the only reasonable
explanation would that chance was involved.
Unfortunately,
there is one flaw with this - we cannot perfectly recreate the events.
In the case of the tossing of a die, this is obvious - no person
could hold and throw the die exactly the same way twice in a row.
And, of course, there would be other factors such as air currents,
the rotation of the earth, the temperature of the die, the effect
of the original throw on the die, and so on. Despite these problems,
it might be thought the conditions could be recreated perfectly
through various means (an incredibly precise robot arm in place
of a person, etc.). However, there is one factor that could never
be duplicated - time. Recreating the event will be just that - a
recreation. If the die comes up three on the first roll and six
on the second, this does not show that it could have been a six
the first time. All its shows is that it was three the first time
and six the second.
Of
course, a possibility remains open - we could travel back in time
and witness the event again. If things turn out differently, then
perhaps we could conclude that we have at last found evidence of
chance. But, of course, we would need to consider the fact that
what changed the outcome was not chance but our presence in the
past.
If
we are willing to consider something even stranger than time travel,
another possibility remains: parallel worlds. Some philosophers
and scientists claim that there are worlds just like ours "out
there." Thus, to prove that chance is real, we would just need
to find evidence of a parallel world just like ours in which, using
the die example, the die came up some number other than three on
the first roll. Unfortunately, this would not help - the die roll
in the parallel world would not be identical to the first die roll
in our world. For the rolls to be identical, the worlds would be
identical. But, in that case we would have just one world, not two.
Thus,
our belief in chance, like our belief in causation, seems to be
based in our psychology and not on any firm foundation. Chance never
had a chance.
Provocations
will next be updated mid September 2003
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