Reading the Catechism of the Catholic Church, one is left with
the impression that Catholic moral teaching is comprehensive,
definite, and unchanging across the centuries. It is a
comforting idea, but not an accurate one. As John Noonan
recounts in detail in A Church That Can and Cannot Change
(University of Notre Dame Press), the church’s moral teaching
has evolved in a number of key areas, such as slavery, religious
liberty, usury, and the dissolubility of marriage. The changes
are significant. As Noonan notes, what was morally permitted
(owning another person) became absolutely prohibited; what was
endorsed as a moral and political good (burning heretics) came
to be seen as a moral and political evil. What was prohibited as
intrinsically wrong (lending money at interest) became
permissible. And what was seen as impossible (papal dissolution
of marriages where one or both of the parties is not baptized)
became possible. What are the ramifications of Noonan’s work for
moral theology and ecclesiology? Catholi