The basis of Christian unity was never meant to be doctrine. The basis of Christian unity was meant to be Jesus Christ. -Norm WakefieldI used to be very upset that some of the same people who had nothing but the highest praise for C.S. Lewis were deeply concerned about my orthodoxy when I started attending an Anglican church. I would have thought that being part of the church of C.S. Lewis would make me relatively free from criticism in evangelical circles. Not so, apparently – Lewis gets a special exemption from the errors of Anglicanism.
This inconsistency is not confined to Lewis. Some of the same people who are extremely critical of Catholicism have nothing but praise for J.R.R. Tolkien and the deeply Christian world of Lord of the Rings, or G.K. Chesterton's robust defense of Christianity against modernism, or Mel Gibson's The Passion. The point is, many people are inconsistent in who they accept as Christians. Even the Catholic church has waffled on this. The council of Trent pretty unambiguously condemned as heretical fundamental protestant doctrines like justification by faith alone, but Vatican II considerably softened the official position on whether or not protestants can be saved.
The tension illuminated by these inconsistencies is this: Christianity is fundamentally credal, but it is also fundamentally about a relationship with Jesus Christ. What do you do when you run into someone who seems to sincerely love Jesus, but has his creed wrong? The default position of many seems to be to define the church in doctrinal terms, but make special exceptions for any devout persons they happen to know who fall outside this doctrine box. It is easy to call the Catholic doctrine of justification foreign to scripture. But excluding Peter Kreeft from the ranks of the church because he is Catholic is another matter. The fact that his books and talks exude a love for Jesus and he claims to be trusting in the all-sufficiency of Christ to save him from his sins gives me the feeling he's being disqualified on a technicality.
There are some ruthlessly consistent people who use some sort of standardized doctrine test to declare people either inside or outside of the kingdom of God, but those people are usually nutcases. If you have ever read a polemic against the false teachings of C.S. Lewis, you know what I mean.
Despite the consistency problems (what a protestant, for example, thinks of the errors of Rome is often largely determined by the character of the Catholics he knows), I think that the intuitive approach described above reveals a fundamental insight: a persons life is the best indicator of his Christianity. It is certainly true that we may misread a person's life, but we also misread the Bible and the amount of error God wills to cover with His grace.
Part of what attracts me to this conclusion is a secret fear that when I stand before Christ at the last judgment, all of my tidy deductive arguments about this or that point of doctrine will fade into irrelevance as I realized that I completely missed the point. I am sure this will happen to quite a lot of people. Thomas Á Kempis expressed the sentiment behind my fear well in The Imitation of Christ:
What does it avail to discourse profoundly on the trinity if you void of humility and therefore displeasing to the trinity? Surely profound words do not make a man holy and just; but a virtuous life makes him dear to God. I would rather feel contrition than know the definition thereof. If you knew the whole Bible by heard, and all the sayings of the philosophers, what would all that profit you without love?