"Laudato Si" is a mediaeval Italian phrase for praised be you. It is drawn from St Francis of Assisi's Canticle of the Sun, a hymn that praises God's presence in nature, and it is a favourite of Pope Francis, who took his papal name from the man who inspired him. Encyclicals generally have a Latin name, but the pope has diverted from custom and practice to emphasize ideas that are important to him. But the subtitle is "On Care for our Common Home." This itself is a slight deviation from those theologians and clerics who claim that heaven is our true home. For the pope our home is here, though he has said that he has not long ere he goes to the house of the Father. Well, we all move house sometimes, but for the moment for all of us home is here, and this means that we are bound to look after it and those with whom we share it.
The encyclical cites previous, of-neglected papal teachings. From Paul the Sixth's encyclical Pacem in Terris [Peace on Earth, 1971] he cites the teaching that the growth of humanity cannot be purely technological, but must go hand in hand with moral and spiritual progress, and notes that this has not happened. From John Paul the Second he draws upon a heightened awareness of the ecological threat to which Paul the Sixth alluded and re-states the principle that ecological well-being and the well being of humans go hand in hand and that we must therefore seek a genuinely human ecology in which humanity and nature are seen as a unity. From Benedict the Sixteenth, he draws upon the statement that social and economic structures must radically change to save the planet and those in it.
But other sources are significant. Following the citation of previous popes's social teaching, he makes extended reference to the Ecumenical Patriarch Bartholemew, head of the Orthodox church, whose teaching on ecological matters Francis cites with enthusiasm. Francis re-states Bartholemew's teaching that we all must be aware that we are guilty of environmental sins in small ways, by excess, by waste and by unsustainable lifestyles. This is the first time that a pope has ever cited a patriarch and is a sign of the growing friendship between Catholic and Orthodox churches that the popes have sought to develop. The encyclical also makes extended reference to Francis of Assisi, the saint whose love of nature was renowned, and he affirms Francis' belief that the earth is our sister. From Francis' disciple Bonaventure he takes the view that St Francis gained his deep love for nature from contemplation of the source of nature, God, and the pope implies that humans too must return to the source of all being to safeguard their common home.
Originality is more often in the combination than the elements themselves. This is not the first encyclical to be addressed to all humankind, that was from John the Twenty Third;and it was not the first encyclical to have a non-Latin title, that was Mitt Brendender Sorge, Pius the Eleventh's anti-Nazi letter in the 1930s. But it is original in its preference for simple language and for citing a source from non-Catholic churches. It is also the first papal encyclical on the environment.