There are two likely paths for philosophers to follow in their encounters with Artificial Life: they can see it as a new way of doing philosophy, or simply as a new object worthy of philosophical attention using traditional methods. Is Artificial Life best seen as a new philosophical method or a new phenomenon? There is a case to be made for each alternative, but I urge philosophers to take the leap and consider the first to be the more important and promising.
Philosophers have always trafficked in thought experiments, putatively conclusive arguments about what is possible, necessary, and impossible under various assumptions. The cases that philosophers have been able to make using these methods are notoriously inconclusive. What "stands to reason" or is "obvious" in various complex scenarios is quite often more an artifact of the bias and limitations of the philosopher's imagination than the dictate of genuine logical insight. Artificial Life, like its parent (aunt?) discipline, Artificial Intelligence, can be conceived as a sort of philosophy--the creation and testing of elaborate thought experiments, kept honest by requirements that could never be imposed on the naked mind of a human thinker acting alone. In short, Artificial Life research is the creation of prosthetically controlled thought experiments of indefinite complexity. This is a great way of confirming or disconfirming many of the intuitions or hunches that otherwise have to pass as data for the sorts of conceptual investigations that define the subject matter of philosophy. Philosophers who see this opportunity will want to leap into the field, at whatever level of abstraction suits their interests, and gird their conceptual loins with the simulational virtuosity of computers.
(The whole paper is now available in Daniel Dennett, Brainchildren, Essays on Designing Minds, MIT Press and Penguin, 1998.)