Digest of terms
a term used by Christian theologian Paul Tillich to identify a distinctive approach to ethics, which gains its meaning by contrast with autonomy and heteronomy. Religious ethics would be heteronomous if they were understood to derive their authority simply from divine decree, in priests, scriptures, or private conscience, without any attempt to think them through in terms of human understanding. As such they would be protested against by advocates of the autonomy of ethics. These would insist that if the human race is ever to escape from its collective childhood, it needs to enable all its members to be independent and to be able to think rationally for themselves.
Tillich's response to this is that the pursuit of reason, as of knowledge and understanding, is not by definition 'against God' or 'ultimate reality'. On the contrary, reasoned argument in its own terms and as combined with relevant religious sources and resources for making moral judgement promotes human integrity in a way that is open to its own depths and to wider inspiration while cooperating with God's spirit at work in all humanity. As such, it is 'theonomous'.
Alternative definitions of theonomy, which reintroduce divine authority as independent of human reason, would in Tillich's terms better be described as heteronomous.