Scientists are quite familiar with the concept of peer review. Whenever a scientist makes a possible discovery, he first informs the scholarly community of his work and allows them to review it. The idea behind this process is that any one expert, no matter how smart or diligent, can make mistakes – but a community of experts will more easily find those mistakes. It is only after something is peer-reviewed that it becomes accepted as valid scholarship.
A similar process occurs in the Church. Throughout her history, people have made claims regarding the deposit of revelation. For example, in the fourth century, a priest named Arius claimed that Jesus was not God, but was instead some great being created by God. He backed his claim by diligent biblical scholarship and then went out proclaiming the truth of his teaching. However, the Christian community tested his claims against what they had been handed on by previous generations of Christians, i.e. against Tradition. They realized that they had been worshiping Christ as God in their liturgies for hundreds of years, so how could he not be God? Even though Arius’ arguments sounded biblically plausible, tradition told the Church that his teachings were false. And eventually, even though it took some time and his arguments swayed many bishops, Arius’ teachings were rejected definitively by the Church. The ‘peer review’ of Tradition, in which the ‘peers’ include all Christians since the time of Christ, found the flaws in his argument.
This peer review process still holds true today, and it applies both to theological scholarship as well as private revelations. If a biblical scholar proclaims a “shocking new discovery” about Jesus (which seems to happen every week these days), the truth of the claim can be reviewed against the beliefs of 2,000 years of Christians. If a person proclaims that they have seen the Virgin Mary and she is giving us a new teaching, tradition can evaluate the truth of this teaching against the teachings of the Church over the centuries. No one person is trusted to know more than millions of Christians through time.
Chesterton famously said that tradition is “the democracy of the dead.” It allows those who have come before us to have their say in what we teach to be true. Like a scientist who needs to be peer reviewed before his work is accepted as valid, so too must all proclamations about the Christian Faith be reviewed by the received teachings of 2,000 years of Christians. Only then will they be accepted as valid.