Style Ontology and the Everyman Rule

One of the constant, unanswerable questions in the universe of beer concerns style.  A gueuze and a pilsner are obviously different beasts, and noting the history, national tradition, and methods of each helps us understand them.  But what about the difference between a German pilsner and helles?  Or, since it has been a topic on the blog this week, Irish and English stout.  One of the blog's best commenters, Daniel Warner, characterizes the thorny issue beautifully in this paragraph:

It's not really a historical question, but one of ontology. Does changing brown for patent malt change the essential nature of a porter? Which is to say, a dark beer of the style made in the UK, made like most UK beers of a combination of UK-style pale malt and cereal adjunct, with UK style top fermenting yeast and UK-style hops. All beers made in the region are made using similar styles and methods, so the "Irish" type is at best a subtype, and one I'm not convinced exists, given that brown malt was phased out almost entirely over the next few decades. [My bold.  Incidentally, "ontology" is concerned with the nature of being.]

There's actually a lot more, including a nice contribution from the Beer Nut.  I won't re-litigate the arguments here--you can go have a look and see where you fall on the (unresolvable) debate.

Source: Beer Growler/Juliano

It reminds me of a dimension to this discussion I've often wanted to include.  The question of style shifts before our eyes depending on what criteria we happen to be using at the time: history? brewing methods? ingredients?  They're all relevant, and depending on what style you're arguing for, you can make a case that a style exists based on a particular criterion.   To help cut through some of the over-considered haze, I'd like people to consider the everyman rule:  If you sat a random person in front of two beers, could she tell the difference?  This is not meant to trump any of the other ways of thinking about beer, just to clarify them.  A random person isn't going to be able to distinguish between a German pilsner and a helles.  Or Dortmund export.  On the other hand the everyman rule would, I think, support a difference between Irish and other kinds of stouts (even if we had to run it as a thought experiment in mid-19th century Dublin).

It's relevant partly as a check against hyper-geekiness.  When you spend a lot of time studying, brewing, and drinking beer, you tend to see subtle differences as gaping chasms.  But I spend a lot of time drinking beer with non-beer geeks, and I sometimes have the emperor's-new-clothes experience when I'm attempting to justify how one beer is meaningfully different from another.  To beer geeks, yes, the distinction between San Diego IPA and Portland IPA has meaning.  To everyone else, this is pointless hair-splitting.  Unless we want beer to become a tangled world of byzantine complexity, it's wise not to ignore that view.  The everyman rule is a good check on over-thinking style.