In some of the comments on Kerry, I’ve read something along the lines of “well, he must just believe in communion as just a symbol of unity or something, rather than as the Real Presence.”

Well, when it comes to Eucharist, there is no “just” a symbol of unity. Comm-union. In this, we are joined, not only with Christ, but with the whole Church through Christ. That’s no modern invention. It’s fundamental to the meaning of Eucharist.

Which is why someone joining in Eucharist who is not unified, heart, mind and soul to Christ through His Church is, indeed, violating the meaning of the sacrament.

(This is also the argument against inter-communion. I, for one, have never understood those who would express a desire to join in the celebration of communion at another denomination’s church. Why? I’m not united to them- why would I want to lie/pretend? By the way, a friend of mine once went ot a Lutheran church (don’t know which kind, sorry.) Right before communion, the minister said, “Those of you who are visitors and would like to receive communion – ” (dramatic pause) – “are welcome to see me after the service for information on how to join our church.”)

To get a good summary of this, and how organic and integral it is, read what the Pope said

Therefore, the profound meaning of the Eucharist is denied, when it is celebrated without taking into account the need for charity and communion. Paul is severe with the Corinthians because “when you meet together, it is not the Lord’s supper that you eat (1 Corinthians 11:20) because of the divisions, injustices and egotisms. In this case the Eucharist is no longer “agape,” namely, expression and source of love. And whoever participates unworthily, without making it bloom in fraternal charity, “eats and drinks judgment upon himself” (1 Corinthians 11:29). “If Christian life is expressed in the fulfillment of the greatest commandment, and that is in the love of God and of neighbor, this love finds its source precisely in the Most Holy Sacrament, which is commonly called: sacrament of love” (Dominicae coenae, No. 5). The Eucharist recalls, renders present and generates this charity.

Let us take up, then, the appeal of the bishop and martyr Ignatius, who exhorted the faithful of Philadelphia in Asia Minor to unity: The flesh of our Lord Jesus Christ is only one, only one is the chalice in the unity of his blood, only one altar, as the Bishop is one” (Ep. ad Philadelphenses 4). And with the liturgy we pray to God the Father: “Grant that we, who are nourished by his body and blood, may be filled with his Holy Spirit, and become one body, one spirit in Christ” (Eucharistic Prayer III).