  If phenomenal consciousness is completely epiphenomenal, as some philosophers believe, then a search for the functions of consciousness is doomed to futility. In fact, if consciousness is completely epiphenomenal then it cannot have evolved by natural selection. On the assumption that phenomenal consciousness is an evolved characteristic of human minds, at least, and therefore that epiphenomenalism is false, then an attempt to understand the biological functions of consciousness may provide the best chance of identifying its occurrence in different species. (See Robinson 2007 for more discussion of this issue.)