Are baptism and the Supper symbols or realities?
It is a false question. Words are symbols, but we know that words have enormous power for good or evil. A flag, a handshake, a kiss, a poster, are symbols but they are clearly as real as stars and snakes and salamanders. So, to say that the Church’s bread, wine, and water are symbols is not to say that they are without value or power, or that they lack “reality.” It is merely to say that whatever power they have is the kind of power that symbols have, and not the kind of power that a combustion engine or a nuclear power plant has.
-Peter Leithart, Against Christianity, 85.