Abstract.The values which guide mental and physical behavior seem to be derived from evolutionary facts. In our brains, selection of genes has tied the experience of pleasure to motivating what nature requires us to do for the good of ourselves, our kinsmen, and our ecosystem. When our brains evolved to house also a cultural heritage (including religion, the motivation of sociocultural goals, and rational discourse), hellish tensions could arise to split brain function (minds) and societies. Salvation could and did come (...) from natural selection's replacement of discordant elements in our heritages by better coadapted ones. In this replacement, human rational decisions participated. Selection also continued to adapt these symbiotic heritages to their common environment. (shrink)