It’s true that contemporary theology about abortion is relatively recent in history, a point that Senator Joe Biden has been making with increasing frequency lately. Dr. Frank Flinn, adjunct professor of religious studies at Washington University in St. Louis and author if the Encyclopedia of Catholicism, agrees:
Democratic vice presidential candidate Joseph Biden is telling the Catholics in his audiences that St. Thomas Aquinas had a different teaching on abortion than the current pope and his immediate predecessors. Many Catholics are saying, “He simply cannot be right.” Well, the short answer is: Biden is right. The news media are saying that American bishops are giving him a theology lesson on abortion. Mr. Biden is in a position to give them one right back.
The Catholic teaching on abortion has complex roots in Jewish teaching, Greek thought and early Christian doctrine. Jewish teaching shows great reverence for life as a gift from God. The law of compensation in Exodus 21:22 makes a distinction between the penalty for striking a pregnant woman that ends in the loss of the fetus (a monetary amount) or the mother (death).
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Today the Roman Catholic Church often likes to promote the theory that its teachings on abortion are eternal. The history of the abortion controversy clearly demonstrates that this theory cannot be true. Whether a Catholic agrees with Joe Biden or not, he is still right about St. Thomas Aquinas and many other authoritative teachers of Catholic doctrine in the past, including popes. Both the current papacy and the American episcopacy themselves stand in need of a lesson in Catholic doctrinal history.
I encourage everyone to read his brief piece on the history of this issue within Catholicism.