Likewise, by "Catholic", I mean "belonging to the Roman Catholic Church". This specifically excludes Protestantism, Old Catholics, Anglicans, Eastern Orthodox, Church of the East, Oriental Orthodox, and so on. "Catholic" as a religion is a very well defined term.
The question keeps coming up if someone can be both Catholic and Anabaptist, or if the two churches and sets of doctrines can somehow be compatible with each other. My argument is that no, they cannot, for several reasons:
- The Roman Catholic Church has practiced infant baptism for a very long time - certainly practiced in the 5th century, and probably practiced going back to the 3rd. This is well-attested. Infant baptism being the norm for Catholic families is taught by the RCC and opposition to infant baptism is taught against by the RCC. The RCC teaches that infant baptism imparts grace to the infant as a sacrament. This doctrine is not controversial and is universally accepted in RCC circles.
- The Anabaptists, on the other hand, have practiced adult (as in capable of making decisions, generally age 11 or older) believers' baptism upon confession of faith since their founding in 1525. They do not believe there is ever a reason to baptise infants. Most Anabaptists don't believe in baptism as a sacrament, although some do, but those who do (perhaps German Baptists believe this) believe it should be practiced by an adult believer after confession of faith.
- The Roman Catholic Church requires one submit to and believe in the pope's ultimate authority over the church. Someone who stops doing this, or a group that stops doing so, is no longer "Catholic". In 1054, a large group decided to reject the pope's authority and are now known as the Eastern Orthodox. Likewise, in the 16th century, Protestants rejected papal authority and became known as Protestants.
- Anabaptists, on the other hand, do not accept the pope's authority at all and never have; their founding confession says this regarding the pope (and infant baptism):
Therefore, for this reason, I do not see that Anabaptism and Catholicism can ever be reconciled. One of them would have to vastly change. Anabaptists who accepted infant baptism would no longer be Anabaptists. Catholics who rejected the pope's authority would no longer be Catholic. (They would now be Old Catholic, or Anglican, or maybe Orthodox.)This excludes all infant baptism, the highest and chief abomination of the pope.
If the pope decided to institute a doctrine of believers' baptism and then also decided to institute there will no longer be heirarchal papal authority, then perhaps it would be possible for Catholics to become "compatible" with Anabaptism. That is a very big "if".