Necessity

Necessity, in the context of modality, refers to situations or propositions that must be true or cannot be otherwise. When we say something is necessary, it means that it is required or essential. For example, in mathematics, the statement "2 plus 2 equals 4" is necessary; it cannot be false. In contrast, a statement like "It might rain tomorrow" is not necessary, as it’s contingent on various factors. Understanding necessity helps distinguish between what must happen and what could happen, guiding our reasoning about possibilities and certainties in different contexts.