Reverend Christopher Kelly states in an article titled "The Catholic Oak,"
"Some oaks are evergreen, most are deciduous, some are trees, a few are shrubs, some have rounded leaves, some pointed. And yet they share certain readily identifiable characteristics: they all have acorns, a certain type of trunk and bark, leaf structure and temperate habitat. The acorn is the simplest proof of oakhood, but of these, some are bitter and others are not."
"A single oak is Catholic," according to Aristotle's usage when it is in accord with the whole oak world. No single oak can say to the others, "I am the True Oak; therefore, you must all be like me." The precise opposite is true: a single oak must agree with all the others to be an oak. And it is not simply all the living oaks that must be consulted, all the oaks throughout history must agree that our single oak conforms to them. Thus, (if any expression of the Catholic Church, adds novelty to the faith once delivered to all the saints...it cannot require that all the other "oaks" conform to it...that is not Catholic, since it conforms neither to the rest of the Churches nor to the early Church doctrine and practice."
"St. Ignatius of Antioch is the first author we know to have used the term "catholic" to describe the true Church of Jesus Christ. In a letter to Smyrna, written between 107 and 117 A.D., he wrote, "Wherever the bishop is, there let the multitude also be, just as where Jesus Christ is, there is the Catholic Church. In other words, around the bishop, the apostolic man, the authorized commission bearer of Jesus, the man who conveys unchanged the original Apostolic message, who is in union with other such bishops: there is the Catholic Church."
"As the oak is identified by its characteristics in accord with the whole oak world, so Catholic worship, theology (dogmatic and moral), and evangelism down the ages determine what we must do now if we are to be truly Catholic. We may still be an English species (Anglican), a western European species (Roman), an Eastern species (Orthodox), (or an ecumenical species - CASC), but the genus (catholica) must be plain to everyone."
In light of the above, the vision for The Catholic Church in America holds that there are some key, essential elements we believe to be common identifying characteristics of true "catholicity." The heart of these common elements we believe to be embodied in historic statements. These include the Vincentian Canon, the Declaration of Utrecht 1889, the Old Catholic Statement of Union, 1911 and the Bonn Agreement 1925. Our prayer is that these essentials will be a starting point for a fresh work of the Holy Spirit in our day leading to a renewed and deepening impetus towards a true Catholic spiritual ecumenism.
Courtesy of "The Communion of International Catholic Communities."