From the article Limitations of Science at the website Undeception.com
I think the point of Dr. Miller’s quote was that even a full description of what physical things occur and how they occur in a mechanical fashion does not preclude a third descriptor: why. Philosophical materialists insist that satisfactory answers to “what” and “how” questions are sufficient, and since they are answerable in the laboratory, the picture of reality that the laboratory furnishes for us is, by their estimation, altogether complete. Theists argue that we should not ignore the question “why”, even though it cannot be recovered by the scientific method; discounting “why” as a valid question shows a presuppositional bias toward materialism and does not constitute an argument for it.