User:Lulz/Chance

Chance1
This is the sense used in the theory of probability. Actually there are three different basic definitions of probability. The range theory defines probability as the ratio of "favourable" cases to "all cases possible", assuming "all cases equally likely" (eg two sides of a coin are equally likely, so the chance of a head is 1:2). The limiting-relative-frequency concept defines probability as the ratio of "favourable cases" to the total number of trials in an indefinite sequence of trials (eg that the long-run ratio of heads to tosses is 1:2). The subjective theory of probability sees it as nothing more than betting odds which follow the probability formulae (eg a person might be prepared to bet evens on a head coming up).

There are variations on these, but all see probability as essentially a feature of human ignorance - none deny the essential determinism of events.

Chance2
This is the sense used in Heisenberg's Principle of Uncertainty.