What's the difference between "possibility" and "contingency"?

Question

I looked them up in Wiktionary. One of explanations of "possibility" is:

A thing possible; that which may take place or come into being.

And one of explanations of "contingency" is:

(countable) A possibility; something which may or may not happen. A chance occurrence, especially in finance, unexpected expenses.

It seems to me that both words refer to "an indefinite thing that may happen in the future". So I'm a bit curious about what's the exact difference of meaning, usage and connotation between these two words in everyday use.

Answer 1

The definitions you have cited make the words appear very similar.

Possibility tends to be used without reference to whether it is planned for or not. Contingency tends to be associated with deliberate plans.

Here are some examples that highlight this, together with short comments about the selected examples. I've taken the liberty of skipping one philosophical definition of contingency since you are interested only in "everyday use":

Possibility noun - ODO

1 A thing that may happen or be the case.

‘relegation remains a distinct possibility’

• 'relegation' might happen, but there isn't necessarily any preparation for it.

1.1 [mass noun] The state or fact of being possible; likelihood.

‘The Fenians always faced the possibility of being infiltrated by British spies.’

• Presumably the Fenians would have prepared for the possible infiltration, but all the sentence conveys is that it was always possible, not necessarily that they prepared for it.

1.2 A thing that may be chosen or done out of several possible alternatives.

‘one possibility is to allow all firms to participate’

• phrasing it this way means that it was considered, but it does not necessarily carry the idea that it was prepared for or acted on.

1.3 Unspecified qualities of a promising nature; potential.

‘the house was old but it had possibilities’

• The potential for the house was recognised, but on its own, the phrase doesn't convey that there was a plan to realise that potential.

Contingency noun - ODO

1 A future event or circumstance which is possible but cannot be predicted with certainty.

‘a detailed contract which attempts to provide for all possible contingencies’

• The contract is the deliberate planning in case the contingencies eventuate.

1.1 A provision for a possible event or circumstance.

‘stores were kept as a contingency against a blockade’

• The stores were kept deliberately 'just in case' of a blockade.

1.2 An incidental expense.

‘allow an extra fifteen per cent on the budget for contingencies’

• The extra money was deliberately budgeted for unforeseen expenses.

1.3 [mass noun] The absence of certainty in events.

‘The event was briefed, and every contingency was mapped out.’

• Mapping out the contingencies was part of the (deliberate) planning process.

Answer 2

When one looks at the default [listed first by the non-historic dictionaries Cambridge, Collins, Britannica, OLD, though not AHD and Wiktionary] sense of the adjective, contingent:

contingent [adjective]:

[1] dependent on or conditioned by something else

• Payment is contingent on fulfillment of certain conditions.
• a plan contingent on the weather

[2] likely but not certain to happen; [quite] possible

...

                                                                                                  [Merriam-Webster]

often, but not always, followed by an on-phrase:

• Social change and historical events are highly contingent processes, in a specific sense: they are the result of multiple causal influences that "could have been otherwise" and that have conjoined at a particular point in time in bringing about an event of interest.                                      [Daniel Little; Understanding Society]

one sees that there is at least a reasonable pull towards the resultative (of conditions obtaining, often though not always as a result of human activity, often undesirable) sense (admittedly not the default sense) for the noun:

contingency [noun]:

1: a contingent event or condition, such as

a: an event (such as an emergency) that may but is not certain to occur

• trying to provide for every contingency

b: something liable to happen as an adjunct to or result of something else

• the contingencies of war

              [+ other senses]                                               [Merriam-Webster]       [bolding mine]

The synonym 'possibility' does not have this ... denotation? connotation?

Answer 3

Possibility - This is referring to a possible outcome of a specific action - there might be several possible outcomes.

Contingency - This is what happens if a possibility turns out to be real.

e.g. There's a possibility that a football team may be in the lead in the first quarter of a game. The opposing team manager might have contingency plans that are put into place if that possibility turns out to be true.

Answer 4

A good explanation of the difference between contingency and possibilty is given in the Maverick Philosopher blog.

A proposition p is possible =df there is a possible world in which p is true.

A proposition p is possible =df it is not necessary that p be false.

A proposition p is contingent =df there is a possible world in which p is true and there is a possible world in which p is false.

A proposition p is contingent =df p is both possibly true and possibly false.