An Explanation Not Yet Known
The Explanation
Our present choices should not be mistaken for an exhaustive list of everything reality could contain.
Future discoveries may reveal new physical principles, new relationships among existing theories, or entirely unexpected features of nature. Such discoveries could change the way the fine-tuning question is understood.
Recognizing this possibility is not an explanation by itself. It is an acknowledgment of the limits of present knowledge.
Supporting Evidence
The history of science repeatedly shows that important discoveries can change the questions researchers ask as well as the answers they consider possible.
Several issues in this investigation—including the cosmological constant, cosmic initial conditions, and the origin of the matter-antimatter asymmetry—remain areas of active research.
Limitations
An unknown explanation cannot presently be tested, compared, or used to account for specific observations. It therefore should not be treated as though it already solves the problem.
Its value is instead to prevent us from creating a false choice among only the explanations presently under discussion.
Questions That Remain
Which future discoveries might change our understanding of fine-tuning, and would they eliminate the question or reveal a deeper form of it?
Intelligent Design Response
Intelligent Design should remain open to correction by new evidence. If future discoveries provide satisfactory natural explanations for observations presently considered evidence of design, those discoveries should be incorporated rather than resisted.
At the same time, the mere possibility of an unknown future explanation does not tell us what explanation best accounts for the evidence available now.