Abstract

This thesis investigates the question of what the contemporary discipline of biology might be able to tell us about human nature which is relevant to doing moral philosophy. I construe the contemporary discipline of biology broadly to include genetics, neurophysiology, and animal and human behavior and their interrelationships. Moral philosophy I take in its classical sense, that is, as a discipline which seeks ethical norms and their foundations. I begin with the assumption that we have a nature such that, if we knew it, we would know what sort of life might be the best sort of life for beings such as us. ;I conclude that we do not have a nature such that we will ever know, in general, what sort of life might be best for beings such as us. At least, we cannot know it aside from the context supplied by our environment, including our culture. This conclusion, however, does not mean that we do not have a nature, if by "nature" is meant "born with certain dispositions, propensities, and rules for learning." There is good evidence from contemporary biology that we have evolved such a nature and that it has a genetic base. But we can manipulate this nature, change it, or ignore it. Human nature, I conclude, is best characterized by its versatility. ;My conclusions regarding human nature can serve as a tool for critiquing moral philosophies. They undermine moral philosophies based on human sentiments or on utility where these depend on our having a consistent nature. On the other hand, philosophies not based on human nature, especially rationalistic ones, receive support. I also conclude that our nature is not only egoistic, but also social and altruistic. This part of my conclusion undermines contractarian philosophies where they are based on egoism and lends support to moral philosophies based on our sociality, such as those centered in the virtues. In the end, these findings lead me to think that the most adequate ethical philosophies will spring from moral systems based on reason combined with moral systems which emphasize the virtues.