Varner, Gary E. "Biological Functions and Biological Interests," Southern Journal of
Philosophy 28(2): pp. 251-270, Summer 1990.
I defend the empirical claim that plants have needs, in some sense in
which simple artifacts do not, and the normative claim that those needs
qualify plants for direct moral consideration. Using the notion of a
biological function we can specify, in a nonarbitrary way, what is and
is not in the 'biological interests' of a plant, and we can say that
plants have interests without implying that simple artifacts do. Certain
inadequacies of the dominant mental state theory of individual welfare
suggest that such 'biological interests' are morally genuine interests,
which qualify their possessor for direct moral consideration.