Dear Joe:

The four organizations specifically mentioned by the Church are the Freemasons, Odd Fellows, Sons of Temperance, and Knights of Pythias. The criteria to judge whether or not a society is prohibited to Catholics is outlined by Archbishop Katzer in a Pastoral (20 Jan., 1895):

"The Catholic Church has declared that she considers those societies illicit and forbidden which (1) unite their members for the purpose of conspiring against the State or Church; (2) demand the observance of secrecy to such an extent that it must be maintained even before the rightful ecclesiastical authority; (3) exact an oath from their members or a promise of blind and absolute obedience; (4) make use of a ritual and ceremonies that constitute them sects."

At one time membership in the Freemasons incurred an excommunication because the Freemasons conspired against the Church. By 1983 there was no evidence of this motive by the Freemasons and thus the auto excommunication was removed. The prohibition for Catholics to join the Freemasons, however, remains because the teachings of the Freemasons is utterly inconsistent with Christianity.

Most secret societies, although they protest that they are not religious, espouse religious ideas that are often naturalism or otherwise contrary to Christianity. 

In this prohibition of membership in secret societies also applies to college Greek Fraternities. The worse of the worse is Kappa Sigma. In the 60s college fraternities had to reveal their secrets to Congress except Kappa Sigma. This is not acceptable. Parents have a right to know what is happening in organizations their children join. From a Catholic point-of-view the bishop must be privy to the secrets in order to determine if the organization is a danger to the faith. Kappa Sigma refuses such access to anyone.

Some will say that the Knights of Columbus are no different than these secret societies, but that is nonsense. The bishop is privy to the secret initiation ritual (which is secret only to not spoil it for newcomers) and all teachings of the Knights of Columbus are in 100% concert with the Church.

As for the Elks and Moose Lodges I am not very familiar with how they operate. From the Initiation Ritual I found online, the Elks Lodges are profoundly silly. Although one must believe in God to join, I notice that Christ is never mentioned. Since the Elks Lodge is mentioned in the book, Secret Societies and the Catholic Church, linked below, I suggest that this society is not for Catholics.

Certainly, the bishop must be allowed access to all rituals and teachings of any organization in order to ascertain whether or not there is a danger to Catholics. If any group refuses that access, then no Catholic should belong.

In general, the "lodge" system, as with the "Greek" system, is rife with problems that should warn away any Catholic.

A Catholic may participate, however, in public activities sponsored by these societies. For example, the Masons in my town sponsor a Thanksgiving dinner for the poor and the Elks have public dances. One can volunteer to hand out Thanksgiving dinners or go to a dance without being a part of the society itself. However, if the dance has a cover charge that benefits the society instead of some charitable cause then it would not be prudent for a Catholic to attend as it would be supporting the society.

For more information check out the Catholic Encyclopedia and also a book published in 1902 by Father Peter Rosen entitled, Secret Societies and the Catholic Church. The book has an imprimatur. Father Rosen mentions the Elks in the book.

God Bless,
Bro. Ignatius Mary