encyclical

1.for an encyclical to be infallible the Pope must speak ex cathedra.

要使通谕不谬，教皇必须发言有权威性。

2.Popes seldom weigh in on economic matters and rarely in the form of an encyclical, one of the most authoritative forms of papal writing.

教皇们很少会讨经济问题，也很少以通谕的形式颁布。通谕是教皇件最具权威性的一种。