Is there Natural Purpose?

In human beings, choice and action require a cause of a different kind to link them. Otherwise a vicious regress breaks out. This is cause in the sense of end or purpose. It stands between choice and action, making a reciprocative causal triad. Yet apart from our projects, this triad obtains in nature too, and for the same reason. In reproduction, as in choice and action, means are activities that are directed to the replication of pre-existing patterns as ends. Further, when agents are taken not as active but as capable of certain activities, the latter are not means as in reproduction but themselves ends. In this sense, it can be said that persons have a natural end as persons, a thesis for which two arguments are proposed