So, my last post attracted this exchange in the comments:

John M. asked:

Here is an argument pattern that I’ve noticed, though I’m not clear if it fits the enthymeme definition:

“Thing A has characteristics X, Y, and Z, so that supports the notion Thing A is good.”
“But Thing B also has characteristics X, Y, and Z, and Thing B is universally considered bad. Having those characteristics doesn’t establish that Thing A is good or desirable.”
“How dare you compare Thing A to Thing B!”

The unstated assumption here, I think, is that Thing A is good, while at the same time the arguer is going through the motions of demonstrating that Thing A is good.

I replied:

That type of argument is tricky. Usually there is some unspoken criteria being left out, or there is a mere focus on surface details. To use a rather extreme example – in some political quarters, a person who is a vegetarian that rejects traditional sexual mores and embraces gun control would be considered an a-ok dude. But that also describes Hitler (Go Go Godwin!). I could see a conversation like the one you mention happening in this way. The problem there is that really, “vegetarianism, gun control, etc.” are being used as markers for other, more basic attitudes towards the world that Hitler did not share. In that case, one would have to delve deeper and see what is really being considered worthwhile (say, vegetarianism being used as a stand in for respect for all life, or something like that).

Since then, I’ve been thinking on this exchange.  I realized what we have here is “synechdoche” as argument through identification.

[First, for those who came in late (or slept through that day in your English class), synecdoche is a literary/rhetorical trope that involves using the whole for the part or the part for the whole.  Some common examples are “the crown” referring to the king, or “The White House” to refer to the President of the USA or even the entire executive branch.  Go look it up on Wikipedia if you need more examples and explanation.]

The problem in argumentation comes from the attempts to create identification between groups and people.  A lot of argumentation, especially in the political and cultural arenas, comes from attempting to convince people to identify with certain people.  That’s one reason political parties trot out celebrities – people want to identify with famous people, and so they will adopt parts of those celebrities beliefs in order to identify with them, regardless of what the merit of those beliefs may be.

So, as in my example above, people will use these “parts” to stand for the whole – a synecdoche of sorts.  Vegetarianism (or Veganism) comes to stand for a larger whole.  A homemade sign outside a house that is on my bike route to work states “Be Vegan.  Save the Planet.”  Here, veganism is considered to be a part that stands for a larger whole.  Clearly, it takes more than just being vegan to save the planet (and I personally think Veganism isn’t a very smart philosophy, but that’s beside my larger point).

The problem John M. referred to above comes when different “wholes” happen to share the same parts, which shows the weakness of argument by synecdoche.  Just because someone claims to be feminist, it doesn’t mean that they automatically share in the entire platform of the Democratic party (though this is the reason many try to claim there is no way Sarah Palin could be feminist at all).

On a more Mormon note, this often happens with religious practices.  Paying tithing, going to church regularly, things such as that are generally used as a synecdoche for claiming someone is a good, believing member of the church – possibly even fairly conservative in their beliefs.  Of course, that isn’t so.  I’m sure we can all think of examples where, when only knowing part, we made larger assumptions about the whole that may have turned out false.

The key to avoiding the problem that John M. and others (I think we all have experience something like that) is to recongize the synecdoche for what it is.  Then move to the larger whole, and start breaking it down into parts to see where the “break” between the two different “wholes” (people, philosophies, practices, etc.) occurs.

I have more thoughts on this that I will likely post sooner or later.