Archaeology, Anthropology, and Interstellar Communication
organization, or perhaps as philosophical challenges.3 All of which is to say that while we can attempt some discussion, or even analysis, of what an ETI might be like, we must remain aware of our fundamental constraints. We can explore those constraints, but we must recognize them—we cannot do anthropology here on Earth “over the telephone,” so why should we expect to do it well over the ether and with another species in an environment we cannot experience?4 These issues can be addressed in relation to some specifics, the sort of concerns any anthropologist or archaeologist has with respect to assumptions about the objects of a study. So we must begin by considering these assumptions. What is necessary in any communication scenario involving ETI, and what limits must be put on our conceptions of possible messages? When answering these questions, we will consider work in cognitive science along with archaeological and historical examples that include rock art, toolmaking, and a 15th-century codex. It is not assumed that systems of explanation are the same as ours, merely that what is explained or known must be about the same universe—and the term universe covers physical aspects of the universe as well as cognitive and behavioral aspects of beings. It is assumed that any ETI will be an embodied intelligence—a being with a brain to control its actuators and to monitor its environment using sensors to record external stimuli such as atmospheric pressure, acoustic pressure, and electromagnetic radiation.
Assumptions—I Physics and Biophysics: We can assume that the physics of the universe is knowable locally. We monitor our local environment and interact with it to make remote observations of other parts of the universe. Plausibly, beings on other planets can do the same. Further, we can assume that the sensory biophysics of any ETI is functionally equivalent to ours. Beings will be able to sense the world—or portions of the spectral data available—because the physics and chemistry of the universe are uniform. But it is not claimed, for example, that
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