"Extra Ecclesiam Nulla Salus"--an Analogy

Nicely done.

Outside the earth there is no life ... and outside the Church there is no salvation? The answer, of course, is simple: [Astronauts] didn't leave the Earth; they just brought it with them. While they slept and walked on the moon, they were eating Earth's food and breathing Earth's air. Everything they had came from back home. So when we say "outside the Earth there is no life," we are saying that all of the means for survival are found on this planet. And when we say "outside the Church there is no salvation," we mean that all the means of salvation -- doctrines, sacraments, and so on -- are found here, uncorrupted by error. Some of these means can exist outside the visible bounds of the Church. for example, Protestants have most of the Bible, along with two of the seven sacraments. Nevertheless, these things are like the food and water on the space shuttle: they're life-giving, but they came from a place where they're far richer, more abundant and complete

--Kevin Knight, quoted in Happy Catholic