7 - Conclusion

Summary

Aristotle appeals in a variety of ways to his theory of natural teleology in order to generate explanations of biological phenomena. At the most basic level, living beings are explained to have the capacities of the soul they have in virtue of those capacities being necessary for the sake of living, and in the case of the more complex and less widespread capacities, in virtue of being necessary for living well. At the more complex level, Aristotle explains that living beings – and also the heavenly bodies – have the bodily parts and features they have for the sake of exercising their vital and essential capacities, or for contributing to the performance of those vital and essential capacities, or because they serve their well-being in some other way.

What unifies these teleological explanations is that they all pick out a function or beneficial end as that for the sake of which some feature is present. In addition, the presence of this function or end is identified as the outcome of the operation of a goal-directed efficient cause (i.e., as being due to the goal-directed actions of the formal nature or soul of a natural being), where this process of coming to be either consists in the realization of a potential for form, or in nature making good use of excess materials.