Resolving Discontinuity: A Minimalist Distinction between Human and Non-human Minds1

Abstract

SYNOPSIS. Our genotype is so similar to those of the African apes, and our last common ancestor with them so recent, that it seems impossible that human and non-human cognition should differ qualitatively. But the outputs of human cognition are unique in their limitless creativity and adaptability. Exaption resolves the apparent paradox. Assume that the power to create symbols emerges from stimulus-stimulus linkages and is latent in many animals, and that the structural side of language emerges from the argument structures inherent in the social calculus associated with reciprocal altruism. These adaptations confer the potential for language. However, creating complex messages requires uniquely long-lasting coherence of neural signals, which depends in turn on the large quantities of neurons unique to Homo. The only difference between human and non-human minds is that we can sustain longer and more complex trains of thought. All else (emotions, rational processes, even consciousness) could be exactly the same. To the best of current belief, the hominid line separated from the rest of the primate family not more than 5‐7 million years ago. We share with our nearest relatives, the bonobos and chimpanzees, close to 99% of our genetic material. In any other cluster of species with similarly close relations, this degree of closeness would imply that those species were extremely similar, both morphologically and behaviorally. Within such a time-frame, for instance, horses have diverged from one another hardly at all, and even in an evolutionary period ten times as long, changes (apart from a significant increase in overall size) are limited to such things as number of toes and size and shape of teeth (McFadden, 1992). However, leaving aside the not inconsiderable morphological differences between humans and other primates, the behavioral differences are incalculable. While other apes show minor differences from one another in such things as feeding patterns and sexual behavior, human behavior differs dramatically, both qualitatively and quantitatively, not only 1 From the Symposium Animal Consciousness: Historical, Theoretical, and Empirical Perspectivespresented at the Annual Meeting of the Society for Integrative and Comparative Biology, 6‐19 January 1999, at Denver, Colorado.