I am working on several manuscripts about the nature and origin of life, including a book, The Quest for a Universal Theory of Life: Searching for life as we don't know it, which is under contract with Cambridge University Press. The latter follows an anthology, The Nature of Life: Classical and Contemporary Perspectives from Philosophy and Science, co-edited with Mark Bedau and already in print (Cambridge University Press, 2010). Among the issues discussed in The Quest for a Universal Theory of Life are: the characteristics and historical development of highly successful scientific theories; strengths and weaknesses of our current scientific understanding of life; promising empirical strategies for searching for a second genesis of life (here on Earth or elsewhere); a roadmap for achieving a scientifically fruitful, theoretical framework for understanding life.

I continue to work on issues concerning the methodology and justification of the practices of historical natural scientists. I am in the early stages of exploring the use of models, especially computer simulations, in the practices of historical natural scientists, including planetary science. I anticipate eventually writing a book on the methodology of the historical natural sciences. This book may end up being more general, covering both the historical and non-historical field sciences.