In his letter responding to my article "Doubt and Faith in Science and Religion" (PSCF 70, no. 2 : 90-100), Martin Huizinga argues that many actual observations and experiences are not contingent on any assumptions. However, this comment illustrates one of the primary points that I made in the article. That is, there are fundamental unprovable assumptions that underlie all knowledge. These assumptions are often held without any conscious awareness. In using observations to construct our understanding of the natural world, we depend on the assumption that our senses provide true information about an external physical reality. In fact, we must assume that an objective physical reality that is accessible to us even exists. This is not trivial.
The equivalent in the pursuit of religious truth, is the assumption that there is a "supernatural" reality. For Christians, that assumption includes the existence of a personal transcendent creator God who is also immanent in the natural world. All our subsequent knowledge must start there.
Keith B. Miller