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A condition can be both necessary and sufficient. For example, at present, "today is the Fourth of July" is a necessary and sufficient condition for "today is Independence Day in the United States". Similarly, a necessary and sufficient condition for invertibility of a matrix M is that M has a nonzero determinant.
In other words, when some factor is necessary to cause an effect, it is impossible to have the effect without the cause. [3] X would instead be a sufficient cause of y when the occurrence of x implies that y must then occur. [2] in other words, when some factor is sufficient to cause an effect, the presence of the cause guarantees the ...
The absence these conditions guarantees the outcome cannot occur, and no other condition can overcome the lack of this condition. Further, necessary conditions are not always sufficient. For example, AIDS necessitates HIV, but HIV does not always cause AIDS. In such instances, the condition demonstrates its necessity but lacks sufficiency.
Causes may sometimes be distinguished into two types: necessary and sufficient. [19] A third type of causation, which requires neither necessity nor sufficiency, but which contributes to the effect, is called a "contributory cause". Necessary causes If x is a necessary cause of y, then the presence of y necessarily implies the prior occurrence ...
The word "cause" (or "causation") has multiple meanings in English.In philosophical terminology, "cause" can refer to necessary, sufficient, or contributing causes. In examining correlation, "cause" is most often used to mean "one contributing cause" (but not necessarily the only contributing cause).
Sufficient and necessary causes [ edit ] Causality, within sociology, has been the subject of epistemological debates, particularly concerning the external validity of research findings; one factor driving the tenuous nature of causation within social research is the wide variety of potential "causes" that can be attributed to a particular ...
For a property to be a necessary condition it must always be present if the effect is present. Since this is so, then we are interested in looking at cases where the effect is present and taking note of which properties, among those considered to be 'possible necessary conditions' are present and which are absent.
A component cause is a factor that, along with other component causes, forms a sufficient cause for a disease. A sufficient cause is a complete combination of component causes necessary for the disease to manifest. Diseases result from a chain of causally related events, starting from an initial event to the clinical appearance of the disease.