Along with philosophers and psychologists from Plato through Maslow, Lee believes that humans progress through hierarchical stages of biological and moral development. Humans, according to the author, also live at different levels of being and participate in biological, social, rational, cultural, and individual activities. At each developmental stage and in each sphere of activity, people have different needs. A hierarchy of species and individual needs provides an objective basis for ethics. This ethical system extends beyond humanity and embraces environmental ethics as well. The...