The sciences are unified by their naturalistic methodology and empiricist epistemology, a unity ... that can take us to the outer reaches of natural phenomena, but never beyond them. When we move beyond the epistemic boundaries that these faculties and rules set for us and the correspondingly limited metaphysical boundaries they enable us to define, we move from the relative epistemological safety of knowledge to the unmapped, supernatural territory of faith.
That seems like a reasonable philosophy of science insofar as it goes. But how then would Forrest have us implement this limitation? For there is a three-way tug of war between method, realism and completeness. One can mandate any two of these three, but not all three. The underlying problem here is that we don't know the truth at the outset.
For instance, if we mandate a naturalistic methodology as do evolutionists, then this restriction may rule out true explanations in some cases. We have no way of knowing if method restrictions will rule out the truth, because we don't know the truth.
This means we'll either have to settle for explanations that may be false (as did Descartes), or for explanations for only the subset of phenomena that match up with our method restriction (as did Bacon).
The first option mandates method and completeness but sacrifices realism. The second option mandates method and realism but sacrifices completeness. Finally, the third option is to mandate completeness and realism but sacrifice restrictions on method. Historically this was the favored position of moderate empiricists.
Within this larger context we can see that Forrest falls into the second option, mandating method and realism but sacrificing completeness. The question for Forrest and the evolutionists then is: What is the boundary between natural phenomena and supernatural phenomena?
Forrest tells us science must never violate this boundary, so it is important that we discern it. We need to distinguish between natural and supernatural phenomena? How can science know when it is investigating a supernatural phenomena rather than a natural one? Bacon wrestled with this problem. What does Forrest have to say?