My mom tells the story that when she was a child, she was not allowed to eat anything which contained ingredients she couldn’t pronounce, as they were probably harmful. This is the same way some Christians feel about ecclesiology: they can’t say it, so it must not be good.
Ecclesiology is just the concept of what the Church is. We all have an ecclesiology, even if only implicit. Is the Church a formal institution or an informal association of people? Is it a holy witness to the truth or a messy hospital ward for sinners? Is it the a tax-exempt charity or a political action committee? Or none of the above? There are many different ideas about the nature of the Church.
Do these ideas matter? In a sense, not nearly as much as other areas of Christian belief. Jesus never said, “You are blessed if you believe X, Y, and Z about the Church.” Nor did Paul write, “If you believe A, B, and C about the Church, you will be saved.” The central message of Christianity is that God became incarnate as Jesus Christ in order to redeem the world and fix the mess that we all have made by his death and resurrection. Christianity first and foremost proclaims Jesus Christ, who he is and what he has done and is doing.
But “not nearly as significant” as the most significant single event in the history of the universe is a far cry from “insignificant.”
Some might point out that ecclesiology remains perhaps the most contentious and debatable area of Christian belief, with more disagreement than agreement on the subject between Orthodox, Protestants, and Roman Catholics. And if the churches have got on well enough without a clear consensus on the subject (unlike, say, the doctrines of the Trinity or Christology), then ecclesiology must not be the most essential.
But again, “essential” is not the same as “significant.”
Ecclesiology makes a difference to many areas of our understanding of Christianity. Here, I will take just one example: ecclesiology determines how we evaluate which religious events are good or bad. In particular, whether a Christian who is not of your group is an ally or a rival, whether you should celebrate or abominate their successes, and whether you regard their ideas are stepping stones or snares, are all questions of ecclesiology which have a large impact on how we live in a society with multiple Christian denominations. A number of examples will clarify the case.
John of Monte Corvino was a Franciscan missionary to China in the early fourteenth century. At that time, there were a significant number of Eastern (non-Latin) Christians in China under the Mongol Yuan dynasty, and because he did not regard their churches as in any way valuable or conferring salvation, he focused his efforts on converting them to his own Latin Christianity. According to his account, he succeeded in converting a prominent statesmen who belonged to the Church of the East, namely King George of the Onggut, and cherished high hopes of leading most of that people into submission to the papacy. By doing so, he elicited strong opposition from the clergy of the Church of the East, and he complained that they were attempting to prevent him from saying mass or baptizing anyone. (It is not simply ironic, but rather a reflection of the ecclesiology of his church, that back in Europe and in the Crusader states his fellow Latin clergy sometimes likewise hindered other Christians from celebrating church services.) His actions and his complaints make sense, if he took a narrow interpretation that outside of his (Latin) Church there could be no salvation. But from an ecclesiology which values ecumenical cooperation (and since 1994 the Vatican has acknowledged that the Church of the East is not teaching Nestorian heresy, as they had previously thought), these strategies are back-stabbing and sheep-stealing. What looks like Christian love and missionary zeal, from one ecclesiological perspective, appear instead as arrogance and hypocrisy, from another.
In 1548, Luther’s followers were in crisis. The Holy Roman Emperor Charles V, a staunch supporter of the papacy against “Lutheran heretics,” had defeated the Protestant princes in the Schmalkaldic War, and he decreed religious uniformity throughout his realm by ordering all people to go back to mass. The only concessions to the reformers were communion in two kinds (bread and wine for laity) and clerical marriage. A revised version the following year explained the doctrine of justification by faith in a Lutheran sense, thanks to the input of Philip Melanchthon, and was more acceptable by some, though not all, of Luther’s followers. Melanchthon argued that the Roman mass itself was adiaphora, neither commanded nor forbidden in scripture, and therefore obedient attendance was permitted. His critics, including Matthias Flacius, said that nothing idolatrous (as they viewed the Roman mass) could be adiaphora, and a split developed between the “Philippists” and the “Gnesio-Lutherans” (the name means the “True Lutherans”), which would only be healed a generation later, after both Melanchthon and Flacius were dead. Was Melanchthon correct to be willing to compromise with the Roman Catholics? Certainly not, if they had nothing to do with Christ’s true Church, as the Gnesio-Lutherans claimed. Were the Gnesio-Lutherans right to break away from Melanchthon and other “compromisers”? Only if preserving the “purity” of their church was more important than unity with Christians who thought differently on these points. (It is ironic that there was a controversy over adiaphora, literally “things that don’t matter.”)
A third example: Rev. Billy Graham preached an evangelical Protestant message of salvation by faith in Christ from the late 1940s to the early 21st century. His revival “crusades” in a location were organized by clergy in that city or area, who would then direct follow-up efforts with new converts and incorporate them into their churches. These clergy would often sit on the platform behind Graham while he preached. Beginning in the late 1950s and early 1960s, Billy Graham’s “crusades” made two inclusive moves. He racially integrated the clergy on the platform, and he invited Roman Catholic clergy to participate in the revivals. These views were not universally popular, and he earned a lot of criticism from more conservative Protestants, especially for encouraging lapsed Catholics to return to the Roman Catholic Church. Ecclesiology again determines whether Graham was right or wrong to cooperate with Catholics. If the Roman Catholic Church is simply the bondage of demonic idolatry, as some of Graham’s critics assert to this day, then sending would-be converts to Christianity to them is to short-change them of salvation. (Lest you think I’m making this up, here is one webpage critical of Graham along these lines, and by no means the most extreme.) But if the Roman Catholic Church is a valid church through which people may experience Christ’s redemption, then Graham’s cooperation with them is another instance of his evangelical priority to work together to spread the good news of Christ’s love and redemption.
Ecclesiological issues inform many of the debates between liberals and conservatives in most major denominations. Among Protestants, the liberal/conservative divide for the past century and a quarter has frequently lined up over the issue whether the Church should seek to ameliorate the world or should seek to rescue sinners out of the world. (Some are increasingly realizing that this need not be an either/or.) Among Roman Catholics, the division between sede vacantists and papal loyalists turns on whether recent popes and the Second Vatican Council have started promulgating falsehood or have merely exercised their divine right of doctrinal definition. Among papal loyalists, the divide between liberals and conservatives includes the question whether the Church should change to accommodate modern notions of progress and mores, or whether the Church should timelessly hold its essential teaching in defiance of contemporary social developments. In order to navigate these debates, and to rejoice in those things which honor our Savior, Jesus Christ, we need an ecclesiology which is accurate and astute. May the Holy Spirit guide his Church into all truth, as our Lord promised.