Let’s consider a commonly used definition of theory. A theory is:
“systematically organized knowledge applicable in a relatively wide variety
of circumstances devised to analyze, predict or otherwise explain the
nature or behaviour of a specified set of phenomena that could be used as
the basis for action” (Van Ryn and Heany, 1992).
More simply put, a theory is a structured logical explanation, or a way of examining or
describing a certain phenomenon, such as the factors promoting or inhibiting health.