The Ascent of Man develops a comprehensive theory of human nature. James F. Harris sees human nature as an emergent property that supervenes a cluster of properties. Despite significant overlap between individuals that have human nature and those that are biologically human, the concept of human nature developed in this book is different. Whether biologically human or not, an individual may be said to possess human nature. This theory of human nature is called the"cluster theory." Harris takes as his point of departurePlato's comment that in learning what a thing is we should look to the...