Terminology Tuesday: Imply/Implication

Imply/Implication: There is an everyday sense of these words which means roughly, 'suggests' or 'leads me to believe', as when the detective says, 'the evidence implies that Smith was present at the murder'. However, the word 'imply' is often used more strictly to mean 'if ... then ...' For example, if someone says, 'the presence of fire implies that there must be oxygen present', they could equally well say, 'if there is fire then oxygen must be present'. In general, to say that 'A implies B' is to say something like 'if A then B', either strictly as in the oxygen example or more loosely as in the detective example. To say that 'A entails B' is usually to say 'A implies B' in this strict usage of 'implies'.1

1. Alec Fisher, Critical Thinking: An Introduction (Cambridge: Cambridge University Press, 2001), pp. 239-240.