Pragmatic marketing inquiry is a simple process that follows the scientific method. It's about as old as Aristotle.
It's mostly useful for providing structure in situations that are inherently difficult to structure. Marketing strategies can be difficult to structure. This approach is meant to force marketers to define, research, compare, test, and revise their hypotheses.
Whether or not you agree with me that marketing strategy is the core of any sustainable business plan, you will probably agree that it's good to encourage marketers to test their theories.