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Theory of chances
(gcide) | Chance \Chance\ (ch[.a]ns), n. [F. chance, OF. cheance, fr. LL.
cadentia a allusion to the falling of the dice), fr. L.
cadere to fall; akin to Skr. [,c]ad to fall, L. cedere to
yield, E. cede. Cf. Cadence.]
1. A supposed material or psychical agent or mode of activity
other than a force, law, or purpose; fortune; fate; -- in
this sense often personified.
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It is strictly and philosophically true in nature
and reason that there is no such thing as chance or
accident; it being evident that these words do not
signify anything really existing, anything that is
truly an agent or the cause of any event; but they
signify merely men's ignorance of the real and
immediate cause. --Samuel
Clark.
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Note: Many of the everyday events which people observe and
attribute to chance fall into the category described by
Clark, as being in practice too complex for people to
easily predict, but in theory predictable if one were
to know the actions of the causal agents in great
detail. At the subatomic level, however, there is much
evidence to support the notion derived from
Heisenberg's uncertaintly principle, that phenomena
occur in nature which are truly randomly determined,
not merely too complex to predict or observe
accurately. Such phenomena, however, are observed only
with one or a very small number of subatomic particles.
When the probabilities of observed events are
determined by the behavior of aggregates of millions of
particles, the variations due to such quantum
indeterminacy becomes so small as to be unobservable
even over billions of repetitions, and may therefore be
ignored in practical situations; such variations are so
improbable that it would be irrational to condition
anything of consequence upon the occurrence of such an
improbable event. A clever experimenter, nevertheless,
may contrive a system where a very visible event (such
as the dynamiting of a building) depends on the
occurrence of a truly chance subatomic event (such as
the disintegration of a single radioactive nucleus). In
such a contrived situation, one may accurately speak of
an event determined by chance, in the sense of a random
occurrence completely unpredictable, at least as to
time.
[PJC]
Any society into which chance might throw him.
--Macaulay.
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That power
Which erring men call Chance. --Milton.
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2. The operation or activity of such agent.
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By chance a priest came down that way. --Luke x. 31.
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3. The supposed effect of such an agent; something that
befalls, as the result of unknown or unconsidered forces;
the issue of uncertain conditions; an event not calculated
upon; an unexpected occurrence; a happening; accident;
fortuity; casualty.
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In the field of observation, chance favors only the
mind that is prepared. --Louis
Pasteur.
[PJC]
Note: This quotation is usually found in the form "Chance
favors the prepared mind." It is a common rejoinder to
the assertion that a scientist was "lucky" to have made
some particular discovery because of unanticipated
factors. A related quotation, from the
Nobel-Prize-winning chemist R. B. Woodward, is that "A
scientist has to work wery hard to get to the point
where he can be lucky."
[PJC]
It was a chance that happened to us. --1 Sam. vi.
9.
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The Knave of Diamonds tries his wily arts,
And wins (O shameful chance!) the Queen of
Hearts. --Pope.
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I spake of most disastrous chance. --Shak.
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4. A possibility; a likelihood; an opportunity; -- with
reference to a doubtful result; as, a chance to escape; a
chance for life; the chances are all against him.
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So weary with disasters, tugged with fortune.
That I would get my life on any chance,
To mend it, or be rid on 't --Shak.
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5. (Math.) Probability.
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Note: The mathematical expression, of a chance is the ratio
of frequency with which an event happens in the long
run. If an event may happen in a ways and may fail in b
ways, and each of these a + b ways is equally likely,
the chance, or probability, that the event will happen
is measured by the fraction a/a + b, and the chance, or
probability, that it will fail is measured by b/a + b.
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Chance comer, one who comes unexpectedly.
The last chance, the sole remaining ground of hope.
The main chance, the chief opportunity; that upon which
reliance is had, esp. self-interest.
Theory of chances, Doctrine of chances (Math.), that
branch of mathematics which treats of the probability of
the occurrence of particular events, as the fall of dice
in given positions.
To mind one's chances, to take advantage of every
circumstance; to seize every opportunity.
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