Lee McIntyre

I Over the last decade or so, much has been written about the new "science of complexity". From journalistic hyperbole to cutting edge research, it is widely assumed that the science of complexity has indeed discovered something new, that is worthy of the attention of scientists and philosophers alike. But what? An overarching principle that connects the study of complex systems across the physical, biological, and social sciences? A method of discovering how order emerges at the edge of chaos? A way to understand phenomena as diverse as the crash of the stock market and the extinction of a species? Of course, there is internal disagreement amongst those who do work on complex systems about how they view their discipline, reflecting varying degrees of optimism and skepticism about any potential unification that the study of complex systems might be able to achieve. 1 Yet lost in the din has been the framing of several basic philosophical questions, without which a serious understanding of the value of complexity theory cannot proceed. Is complexity theory based on claims that are fundamentally epistemological or ontological in nature? Is the debate now going on in the science of complexity merely the old one about indeterminism versus hidden variables, already familiar to us from quantum mechanics? That is, is complexity an artifact of the world or of our understanding of the world? What difference does it make? Is complexity real or only a function of our limited understanding? Indeed, what sort of ontology is consistent with the assumptions made by complexity theorists? Are we required to give up determinism? Is complexity merely a practical problem of our understanding, even if a deep one? It has long been a truism of the philosophy of science that good philosophical work cannot be done unless it is informed by ongoing science. Similarly, one might here pronounce that good scientific work should be informed by philosophy. With that in mind, I shall try here to raise several philosophical issues that seem to have been