1.1.1.30. The family is an incomplete society that can attain to some common goods.

"There are certain common goods to which a family can attain: the common celebration of feasts, certain truths, the beauties of music, dance, and so on, and above all the tranquility of order of its own life... A family is thus in another sense incomplete, as it is naturally ordered to a greater society that enables it to achieve its own common goods better and to share in other, greater common goods."