This is an oak tree (or is it a glass of water?)

I always love stumbling across cool and interesting stuff that you'd probably otherwise never hear about. The chains of links that make up modern life are extraordinarily convoluted. Are they not.

So why am I writing about an oak tree? And not even a physically present one at that, as far as appearances are concerned, but one present in substance, though really present. (Dedicated Roman Catholics may tune out now.)

It all started on Christmas Eve when I took some Asian friends to a High Mass of Christmas Midnight as well, umm, "tourists" is I guess the right word. Not having been inside a church for many years, the service got me thinking once again about that most astonishing yet very commonly held belief in the doctrine of transubstantiation. For those whose tongues have just twisted up reading that word, transubstantiation is the belief held by the vast majority of Christians that, in the Holy Communion, when the priest consecrates the bread and wine, saying the words "This is my Body" and "This is my Blood" the substance of the bread and wine disappears, while 'only' the accidents - their appearances, their colours, tastes, smells, everything that makes them physically apparent as bread and wine in other words, remain. The substances however - substance being something like that which transcends that which is simply apparent to our senses, being the 'underlying' reality of any object - these substances of the bread and wine are literally transformed into the substance of the Body and Blood of Jesus Christ. Not just symbolically, or metaphorically, but really and essentially. In practice, this means that the bread and wine are to be worshipped and adored as Jesus Christ himself. Which Catholics do when they partake in the Exposition of the Blessed Sacrament - where a little piece of blessed bread is placed into a special container called a monstrance and which people bow down to and pray to as God. If you ever have the chance, attend a Benediction service. The sight of a crowd of people kneeling to and worshipping a little bit of bread is so bizarre that there's almost something subversive about it.

Anyway I was reading through the article on transubstantiation at Wikipedia when I saw a link to an artwork called An Oak Tree which is basically a parody of the doctrine of transubstantiation. To quote from the Tate Modern website, which has a copy of it on display:

An Oak Tree consists of an ordinary glass of water placed on a small glass shelf of the type normally found in a bathroom, which is attached to the wall above head height. Craig-Martin composed a series of questions and answers to accompany the objects. In these, the artist claims that the glass of water has been transformed into an oak tree.

Specifically, to quote from the accompanying text which can be retrieved at a