I propose a proof of the Real Presence of Jesus in the Holy Eucharist. Of course, I'm not talking about a proof among physicists or philosophers. I'm talking about a proof among Christians, among those who accept the reality of a personal, loving, yet infinite God; Whose Son became one of us to offer Himself in sacrifice for our sins, so that we could be eternally happy.
Here's the proof:
First, consider the meaning of the term "love," as synonymous with "charity:" It means to "will the good of another." I could get into various manner of explanations how that translates (and doesn't translate) into other forms of what we call "love" in this life, but we don't need to in order for most Christians to agree: When we say "God loves me," or "God is Love," that's what we're talking about: To will the good of another.
So, if God is all-good, and indeed the source and very definition of "good," then what greater good can one will for another than union with God? Christians believe that this is our ultimate destiny if we live according to God's plan, and is the very definition of Heaven.
Jesus taught that the Kingdom of Heaven is "at hand," and one way in which that is fulfilled for Catholics is in the reception of Holy Communion, which we believe to be the real Body and Blood of our Lord. In receiving Holy Communion and in our membership in a Church which regularly receives Holy Communion, we experience union with God right here on earth, as an aid in our daily struggles with the forces of evil and spiritual laziness. It is our strength and refreshment in running the race that St. Paul has referred to.
But here's the kicker: Suppose that we Catholics are wrong. Suppose that what we receive in Holy Communion is only bread and wine, unchanged; that the words of the priest echoing Christ, "this is My Body," are only symbolic and not significant. What then?
What it means is that we, in our imagination, in our speculation and play-acting, have concocted an act and of love that exceeds the will and action of God Himself.
We're not talking here about some childish (or feminine) logic of "If you loved me you would do what I want." This is more syllogistic than such tantrums. What Catholics believe is that at Mass, Christ places His entire Self, body, blood, soul, and divinity, into a form that we can consume for the purpose of regular true union with Him. If that is not the case, then our expectations of love have truly exceeded the gifts that God has seen fit to give.