Now it is obvious that a gift bestowed by one party upon another may be important either in consequence of the value of the gift itself, or by reason of considerations derived from the parties concerned in the giving and receiving. The ordinary food, which sustains us, is an instance of the first kind: it has its value in itself; it is the physical instrument of our support. We may find examples of the other sort in the Old Testament. The "ribbon of blue," which the Israelites received as an article of dress by God's appointment, was of no value in itself : its effect was derived solely from the associations to which it gave rise in the minds of the wearers. Here then was a gift, which was only rendered important by the state of the receiver. Again, when it pleased God to put His Bow in the cloud, here was a thing which neither was of value in itself, nor yet derived it from the disposition of the spectator. The Bow had no tendency to prevent a deluge; it only expressed the intention of Him who put it there. So that we have three different ways in which a gift may be important; first, from its own value; secondly, from the state of the receiver; thirdly, as expressive of the intention of the giver.
Robert Isaac Wilberforce, The Doctrine of the Eucharist, pp. 32-33.
Wilberforce, at this point in time an Anglo-Catholic, notes that theories of the Eucharist tend to divide precisely along these lines. He later notes that you can get the same division in another way. Take the general statement, "This is X." I could be intending to identify this as X; or mark the fact the fact that this is X by representation. An example of the first is to say "This is Caesar" while introducing someone to Caesar. If we are not talking identity, we are talking representation, and there are two ways that occurs: either their is a naturally rooted likeness, or there is a fiat or intention of authority. For instance, I could say "This is Caesar" of a statue of a Caesar; or I could say "This is Caesar" of a book that Caesar wrote. So it is when we think about "This is My Body":
Thus, then, we have three senses in which the expression, "This is" might be employed. First, it may imply identity ; secondly, it may imply that kind of representation which derives its force merely from the effect produced upon the spectator or receiver; thirdly, it may imply that kind of representation which is dependent only upon the intention of the author or giver. Now, when we proceed to apply this to the case before us, and ask which of these three relations was intended by Our Lord, when He said, "This is My Body"; we are met at once by the fact that these arc the three alternatives, which we have already had before us in the second chapter (p. 34), as the theories, respectively, of the ancient Church, of Zuinglius, and Calvin. The principle of identity is coincident with that of the ancient Church, which supposed that the Holy Eucharist derived its value from the reality of the gift bestowed: that principle of representation which depends upon the opinion of the spectator, is plainly the theory of Zuinglius, who maintained that the Holy Eucharist derived its efficacy solely from the disposition of the receiver: lastly, that principle of representation which depends upon the intention of the author, agrees exactly with the system of Calvin, by whom the decree of Almighty God was affirmed to be its sole consecrating principle.
Robert Isaac Wilberforce, The Doctrine of the Eucharist, p. 115.
