Final answer:
In the context of the question, pragmatics is the study of the use of language in context and the assumptions made to make an utterance meaningful. It is concerned with the reasons behind why we say things and how the implicit meaning is derived from the context.
Step-by-step explanation:
The concept that revolves around the implicit assumptions made to make an utterance meaningful or appropriate is anchored in the field of Pragmatics. In the given example 'Mike passed the test', pragmatics enables us to interpret the meaning of this sentence within a given context which may imply expectations such as the test being challenging, or that Mike had studied for it. This differs from Semantics, which is concerned with the meaning of the words and morphemes themselves, Syntax, the structure and organization of sentence components, and Morphology, the study of the forms of words and their smallest meaningful units
Understanding language through pragmatics also engages the idea of performativity, where speech acts perform functions beyond mere description. The words carry an intent to achieve a response or result. This concept is critical in recognizing that language not only communicates information but also fulfills social purposes.