Interstellar Intersubjectvity: The Significance of Shared Cognition for Communication, Empathy, and Altruism in Space

What kind of indispensable cognitive ability is needed for intelligence, sociability, communication, and
technology to emerge on a habitable planet? My answer is simple: intersubjectivity. I stress the
significance of intersubjectivity, of shared cognition, for extraterrestrial intelligence and interstellar
communication, and argue that it is in fact crucial and indispensable for any successful interstellar
communication, and in the end also for the concepts that are focus of this volume, empathy and altruism in
space. Based on current studies in cognitive science, I introduce the concept of intersubjectivity as a key to
future search for extraterrestrial intelligence, and then explain—leaning on phylogenetic, ontogenetic, and
cultural-historical studies of cognition—why intersubjectivity is a basic requisite for the emergence of
intelligence, sociability, communication, and technology. In its most general definition, intersubjectivity is
the sharing of experiences about objects and events. I then discuss what “intelligence” is. I define it as
cognitive flexibility, an ability to adjust to changes in the physical and socio-cultural environment. Next, I
discuss sociability and complex social systems, and conclude that we probably can expect that an
extraterrestrial civilization which we can communicate with has a high degree of social complexity, which
entails a high degree of communicative complexity and high degree of cognitive flexibility. Concerning
communication, I discuss intention, attention and communicative complexity. I also stress three sociocognitive
capacities that characterize advanced complex technology: a sustainable, complex social system,
with a regulated system for collaboration, such as ethics; complex communication for collaboration and
abstract conceptualization; and a high degree of distributed cognition. Finally, if we conclude that
intersubjectivity is a fundamental requisite, we then have some options for future interstellar
communication. We should target Earth analogues, monitor them, and finally initiate an interstellar
intersubjective interaction.