ABSTRACT:In investigating convergent minds, we need to be sure that the things we are looking at are both minds and convergent. In determining whether a shared character state represents a convergence between two organisms, we must know the wider distribution and primitive state of that character so that we can map that character and its state transitions onto a phylogenetic tree. When we do this, some apparently primitive shared traits may prove to represent convergent losses of cognitive capacities. To avoid having to talk about the minds of plants and paramecia, we need to go beyond assessments of behaviorally defined cognition to ask questions about mind in the primary sense of the word, defined by the presence of mental events and consciousness. These phenomena depend upon the possession of brains of adequate size and centralized ontogeny and organization. They are probably limited to vertebrates. Recent discoveries suggest that consciousness is adaptively valuable as a late error detection mechanism in the initiation of action, and point to experimental techniques for assessing its presence or absence in nonhuman mammals.The title of this symposium is "Convergent Minds." I wish to raise some questions about both words in that title.For two things to qualify as convergent minds, they have to be (a) convergences and (b) minds. The first qualification is easier to evaluate than the second. The word "convergence" has a special technical meaning in evolutionary biology. For those who are used to thinking in phylogenetic terms, what follows may be obvious. But it may nevertheless be worth pointing out, because experience shows that even people who are very sophisticated biologists in other respects sometimes make mistakes in evolutionary thinking.Determining whether a particular resemblance between two species represents a convergence or not requires that we know how they fit into a larger phylogenetic picture -the tree of evolutionary relationships -and what the trait in question looked like in their last common ancestor. In general, a trait that was present in that ancestor cannot be a convergence between two of its descendants. This entails that (for instance) no mental properties that humans share with chimpanzees, our closet living relatives, can be All this has a bearing on the way we need to think about these issues. The socalled mirror test for self-awareness developed in 1970 by G. G. Gallup, Jr.[1] provides an example of why and how phylogeny matters. In this test, the experimental subjects are anesthetized and have a visible mark placed on their faces. Control animals receive a mark that is invisible but feels and smells the same. After recovering from anesthesia, each subject is presented with a mirror. If, upon seeing their reflection, the experimental subjects touch or otherwise clearly respond to the mark on their faces but the control subjects do not, the species passes the test.This test has been interpreted as an index of awareness of self, of one's own body as a thing. The meaning of the test...