The companion question to the one raised in Chapter 4 —is there a common logic?—is: is there a common ontology? Is there just the one world to which all ontological theories are directed, at which they aim, and which they either succeed or fail to describe and explain? Or should we acknowledge a plurality of worlds, each an independently valid object of investigation?
The two contrasting answers to those questions correspond, very broadly, of course, to two well-known radically opposed types of position in the philosophy of science, the plural-world answer to philosophical relativism, the one-world one to one or other of a variety of brands of philosophical realism. Realism insists that there is just the one world for any scientific enquiry to investigate. So in that sense if we find Westerners and Chinese, for instance, differing, they must be thought to be just giving different accounts of the same world, the only one there is. But against that, the relativist insists that truth is relative to individuals or groups. So in that sense we could allow that Westerners and Chinese do inhabit different worlds and further that there is no single world by reference to which their accounts can be judged more, or less, adequate.
What light can be thrown on these questions if we focus on early Chinese and Greek cosmology? First I shall examine briefly the nature of some of the differences in the world-views we actually find in ancient Chinese and Greek writers. That will lead me to some reflections on the philosophical issues and how they relate to problems of historical interpretation. Building on some familiar, if still sometimes contested, ideas from the philosophy of science, namely that all observation statements are more or less theory-laden, and the underdetermination of theory by data, I want to make a claim for the multidimensionality and openendedness of the data—of what there is for a theory to be a theory of—and warn against assuming that we know in all cases what it should be of.