Later, in the Foundations of the Metaphysics of Morals (1785), Kant would distinguish between “things” and “persons” (4:428), describing the former as natural means and the latter as rational ends. Persons are free; what distinguishes them is their will, a faculty of determining oneself to action (4:427).  Self-determination is the basis of freedom; necessitation is the mark of nature. The New Elucidation supplies the unified ground for this dichotomy. Autonomy and heteronomy are a matter of dynamic degree.  Persons and things alike are energetic bundles of collocated forces, but the superior rational force of persons can resist others and is capable of autonomy.