Levels of Functional Equivalence in Reverse Bioengineering

Both Artificial Life and Artificial Mind are branches of what Dennett has called reverse engineering: Ordinary engineering attempts to build systems to meet certain functional specifications; reverse bioengineering attempts to understand how systems that have already been built by the Blind Watchmaker work. Computational modeling (virtual life) can capture the formal principles of life, perhaps predict and explain it completely, but it can no more be alive than a virtual forest fire can be hot. In itself, a computational model is just an ungrounded symbol system; no matter how closely it matches the properties of what is being modeled, it matches them only formally, with the mediation of an interpretation. Synthetic life is not open to this objection, but it is still an open question how close a functional equivalence is needed in order to capture life. Close enough to fool the Blind Watchmaker is probably close enough, but would that require molecular indistinguishability, and if so, do we really need to go that far?