This article offers a general definition of self-knowledge that embraces all forms and levels of self-knowledge in animals and humans. It is hypothesized that various levels of self-knowledge constitute an ordinal scale such that each species in a lineage displays the forms of self-knowledge found in related species as well as new forms it and its sister species may have evolved. Likewise, it is hypothesized that these various forms of levels of self-knowledge develop in the sequence in which they evolved. (...) Finally, a general hypothesis for the functional significance of self-knowledge is proposed along with subhypotheses regarding the adaptive significance of various levels of self-knowledge in mammals including human and nonhuman primates. The general hypothesis is that self-knowledge serves as a standard for assessing the qualities of conspecifics compared to those of the self. Such assessment is crucial to deciding among alternative reproductive and subsistence strategies. The qualities that are assessed, which vary across taxa, range from the size and strength of the self to its mathematical or musical abilities. This so-called assessment model of self-knowledge is based on evolutionary biological models for social selection and the role of assessment in animal communication. (shrink)

After rejecting Carruthers' conflation of levels of consciousness as implausible and conceptually muddled, and Carruthers' claim that nonhumans are automata as undermined by evolutionary and ethological considerations, we develop a general criticism of contemporary philosophical approaches which, though recognizing nonhuman consciousness, still see animals as mere receptacles of experiences. This is, we argue, due to the fact that, while in the case of humans we grant a self - something that has not only a descriptive but also a prescriptive side, (...) requiring at least non-interference - in the case of nonhumans we focus only on the descriptive aspects. Consequently, we treat humans as equals whatever their capacities, but we order nonhumans in a hierarchy based on their cognitive level. We conclude that such double standards are not only inconsistent but also self-serving. (shrink)