When one group in the habit of ridiculing an opposing group's beliefs, the easily attacked topics become customary. Mentioning them is so commonplace that no additional explanation is necessary anymore. They typically act as familiar, comforting reference points to casually toss in with other remarks. "Well, we shouldn't be shocked by this, after all. Don't ever forget that the mixed-up people we're talking about also believe _____."
For example, the people on the other "side"—I mean those who still follow the set of beliefs that I scrapped—often parrot the superficial story that a lack of sound religious commitment forces the lack of sound ethical commitments. Their false presumption is that ethics are always shaky and individualized apart from systematized religion's supposed timelessness and objectivity. They imagine that people without religion can't have steady principles to work with. Unbelievers' rootless ethics are to blame for every "incorrect" view and behavior. Their morality is said to be hopelessly deficient because they're inventing right and wrong however they wish.
At one time, I would've glibly agreed that this prejudicial story is self-evident. Needless to say, now I object to virtually every aspect of it, from start to finish. I've become part of the group it stigmatizes and seen for myself that it's wrong about us. Fortunately, we can console ourselves with the numerous targets that religious beliefs richly offer us in return. In my setting, usually these take the form of peculiar Christian myths and doctrines. Transubstantiation certainly fits that demand. It's the doctrine that a ritual can replace the substance of food and drink with the "sacred presence" of Christ. Its plain definition is enough on its own to stand out as bizarre and questionable. Quoting the belief of literally eating the real substance of a god suffices as an open invitation for biting commentary.
Simply put, it presents endless possibilities for wisecracks. Let me emphasize that that's mostly fine with me. I'm not broadly opposed to jokes about an idea...especially the rare jokes which manage to be funny and original. Calling attention to an idea's absurdity shouldn't be confused with "insulting" the idea's followers. Too many nations have created oppressive laws through that confusion. Though, at the same time, the more that a joke strays off topic and verges on outright jeering at people, the less I like it. And back in my former days, the more likely I would've been to briskly skip over the joke's message altogether.
My quibble is something else: the humorous treatment of transubstantiation risks an underappreciation of its twisted philosophical side. When a critic shallowly but understandably chuckles that after transubstantiation the items are visibly no different than before, they're not responding to the doctrine's convoluted trickery. According to its premises, the change wouldn't be expected to be detectable anyway. Everything detectable is dismissed as an attribute (some writings use the word "accident" as a synonym of attribute). But the ritual solely replaces the substance.
The distinction between attribute and substance is strange to us because it's a fossil from old debates. These debates' original purpose was to analyze the relationships among the multiple parts of conscious experience. If someone senses one of their house's interior walls, they may see the color of its paint, feel its texture, measure its height, and so on and so on. Ask them twenty questions about it, and the responses build a long list of attributes. After the wall is repainted or a nail is driven into it to hang a picture, then a few of the wall's attributes have changed. But the wall is still a wall. The substance of what it is hasn't changed. After a demolition crew has blasted away at a brick wall, and left behind a chunk, the chunk is still a wall; it's a wall with smaller attributes. In this scheme, a thing's substance is more like an indirect quality, while direct observations of the thing yield its attributes. The attributes are the mask worn by the thing's substance, and the mask has no holes.
The transubstantiation doctrine reapplies such hairsplitting to justify itself. It proposes that the items' attribute side is kept as-is and Christ's presence is on the items' substance side. By a regularly scheduled miracle, the presence looks like the items, tastes like the items, etc. It's subtler than transformation. How exactly is the process said to occur? The answer is mystery, faith, ineffability, magic, or whatever alternative term or combination of terms is preferred. The doctrine asserts something extraordinary, but then again so do official doctrines about virgin births, 3 gods in 1, eternal souls. Merely saying that it violates common sense isn't enough; common sense can be faulty. And merely highlighting its silly logical implications doesn't address its base flaws.
I think it's a fruitful exercise to articulate why the core of it, the split between attribute and substance, isn't plausible. The first reason is probably uncontroversial to everybody whose beliefs are consistent with materialistic naturalism: human knowledge has progressed in the meantime. We can catalog an extensive set of a thing's innate "attributes" through reliable methods. The discoveries have led to the standpoint of understanding a thing through its attributes of chemical composition, i.e. the mixture of molecules of matter within it and the molecules' states. This standpoint is deservedly applauded for its wide effectiveness because, as far as anyone has convincingly shown, human-scale attributes derive from these composition attributes. (Emergence is a strikingly complex form of derivation. Its turbulent results are collectively derived from the intricate combinations of many varied interactions in a large population.)
Asking another twenty questions to gather more attributes isn't necessary. Ultimately, the composition attributes are exhaustive. Removing or modifying these wouldn't leave untouched a remaining hypothetical "substance" of some kind. These have eliminated the gap in explanation that substance was filling in. These aren't on the surface like the attributes obtained by crudely examining a thing's appearance. The suggestion that all factual examination only goes as deep as a thing's outside shell of attributes stops sounding reasonable when modern examination is fully sophisticated and penetrating.
The second reason why the split between attribute and substance isn't plausible is more debatable, although I sure restate it a lot here: the meanings of thoughts should be yoked with actions and realities (outcomes of actions). The connections might be thinly stretched and/or roundabout. At the moment the actions might only be projected by the corresponding thought(s), but if so then there are unambiguous predictions of the real outcomes once (or if) the projected actions take place. The actions might be transformations of thoughts by the brain: recognition, generalization, deduction, translation, calculation, estimation. Under this rule, thoughts of either a thing's attributes or of its substance could mean less than initially assumed.
Attributes are marked by tight association with particular actions considered in isolation. Wall color is associated with the action of eyeing the wall while it's well-lit or capturing an image with a device that has a sufficient gamut. A wall dimension is associated with the action of laying a tape measure along it from end to end, for instance. Substance is marked by the inexact action of classifying things, perhaps for the goal of communicating successfully about them using apt words. It's an abstraction of a cluster of related characteristics. For a wall, a few of these characteristics are shape, i.e. length and height longer than depth, and function, i.e. enclosing an interior space from an exterior space. When the thing matches "enough" of the cluster, the average person would lean toward classifying it as a wall.
The observer is the one who decides whether to treat a characteristic as a flexible attribute or a member in the abstract cluster of a given thing's "essential substance". This is in line with the composition standpoint, which conveys that particles are indifferent to the more convenient labels people use for larger formations. There isn't anything embedded in each particle that evokes one of these categories over the other. The composition standpoint asserts that particles of the same kind are freely interchangeable if the particles' relevant physical properties are alike.
Indeed, particle interchangeability happens to be doubly significant because, as we all know, things deteriorate. A thing's owners may choose to repair or replace its degraded pieces. When they do, they've removed, added, and altered a multitude of its particles. Yet they may willingly declare that the thing is "the same" thing that it was before, just marginally better. In other words, the substance of it hasn't been lost. Like the famous Ship of Theseus, cycles of restoration could eventually eliminate most of the thing's original particles—which may be presently buried in landfills or turned to ashes by fire. Meanwhile biological contexts withstand continual flows of particles too, as cells die, multiply, adapt. If the action of declaring a thing's substance "unchanged" continues on despite its shifting composition, then the meaning of its substance apparently isn't even bound to the thing's matter itself. Part of the substance has to be a subjective construction.
Nevertheless, the consequence isn't that the entire thought of substance must be discarded as utterly false or fake. The coexistence of objective and subjective parts underpins a host of useful thoughts—such as self-identity. Rather, the need is to remember all the parts of the meaning of substance, to avoid the mistake of interpreting it as if it's an independent quantity or quality. Such a mistake could possibly feed the curious conjecture that a wielder of uncanny powers can seamlessly substitute these independently-existing substances upon request...