Recently, some coworkers asked me the singular question of our age: is a hot dog a sandwich?
If you’re not familiar with the pop-philosophy question, let me google it for you: to quote a 2015 article on the subject, “The debate over hot dogs’ sandwich status has raged for so long on the internet that asking someone whether he or she believes a hot dog to be a sandwich has itself become something of a web-wide in-joke”. (And yes, my coworkers are indeed the sort of folks who would lob web-wide in-jokes at me.)
The denizens of the aforementioned internet have gone into deep debates about the status of hot dogs, even going so far as to coin words for their factions, like “seamists” and “fillingists”. Some have even argued that the answer “exemplifies how the government manipulates consumer interests to reap the largest possible profit for itself.” Goodness!
In the heat of the moment, I gave some relatively hemming answer like “it depends on what the definition of is is ...”. But as good questions tend to do, it stuck in my background processor overnight, and I ended up working out a much better answer, which I am now 110% confident can resolve this dispute across the entire internets, for ever and ever, amen.
Hot dogs are not sandwiches; and, the proof is that this is a funny question.
Let’s set a little groundwork. What we’re debating, when we discuss this weighty question, is not mere surface wordplay. The strings of characters in question, “hot dog” and “sandwich”, are just arbitrary labels; if we were speaking in Spanish, the labels would be different (“pancho” and “emparedado”, respectively). Esa no es la pregunta.
The actual question here is about the abstract categories that underlie our use of the words. Categories, as I’m using the word here, are definitions that collect some set of instances under common criteria. They’re the boundaries of our conceptual sets, our tools of perception for essences in the world .
So the hot-doggo debate is really over whether the categories commonly pointed to by the labels “hot dog” and “sandwich” are one and the same. But the options aren’t actually just a simple “yes” or “no”; if you think of categories as sets, there’s a more complex possible layout of answers:
(a) No sandwich is a hot dog, and no hot dog is a sandwich; they're disjoint
(b) Some sandwiches are hot dogs, and vice versa; they intersect
(c) Every hot dog is s sandwich, and vice versa; they're the same
(d) Every hot dog is a sandwich, but some sandwiches are not hot dogs
(e) Every sandwich is a hot dog, but some hot dogs are not sandwiches
With this more sophisticated version of the options, it’s clear that the debate is really between (a), (b), and (d). Nobody thinks that a PB&J sandwich is really a hot dog, so (c) and (e) are out.
But that still leaves us in a pickle; which of these are right? That depends entirely on how we draw the categories, of course.
I’m operating from a view that categories aren’t eternal, indivisible entities, but instead, categories are predicates: that is, rules for identifying whether any given instance is in or out of the category. The rules we use to define the category of “sandwich” determines whether any particular lump of meat and bread is one, or not.
And, sadly for those who would like an ultimate answer to this question, a category’s rules are often arbitrary. The layout of a person’s categories is epichoric–local to a particular place and time–and it arises alongside your language and your culture. The boundaries are fuzzy, not crisp; this is because most categories are implicit and consensual, not explicit and formal. There’s no official arbiter of the true meaning of “sandwich” or “hot dog” (the existence of a “National Council On Hot Dogs And Sausages” notwithstanding). We should expect that different groups of people, and even different individuals, carry around a slightly different sense of the boundary lines, something like this:
In fact, even a single brain will draw these boundaries differently over time, as it incorporates more examples that reinforce one or another view. A child who’s repeatedly told “That’s not a sandwich, it’s a hot dog” will internalize this categorization rule, even if there’s no logical basis for it. An adult brain, too, is still soaking in examples; say you happened to drive past this billboard every day on the way to work:
Over time, even (especially!) if you didn’t consciously notice it, it might tip the scales of your wet neural net towards the “hot dogs are inside the sandwich circle” interpretation.
Outside the rigorous bounds of mathematics, the best we can collectively do at the “true” delineation of a category is the popular vote ; there’s no underlying truth other than the aggregation of all our individual category detectors. There’s no category police, nor could there be, since categorization is a fundamental function of language, and language isn’t under any centralized control. (Except for French.)
Solving The Riddle
(Warning: in the time-honored tradition of philosophers, we’re getting into “squeezing the joy out of a joke by explaining it to death” territory.)
Why am I writing about the hot-dog-versus-sandwich question? Besides my love for slightly out-of-date internet memes (see also my undying love of Homestar Runner), I’m writing about it for the same reason as everyone else: because it’s funny.
And why are things are funny, in general? Because they violate your expectations. In this case, the expectation that’s being violated is that it’s obvious what a sandwich is and is not. We expect our category for “sandwich” to be as simple and mundane as ... well, as sandwiches themselves are.
But surprise! The category is actually more nuanced than that; it doesn’t strictly follow simple rules you could write down (like “bread wrapped around non-bread food”). It’s not a clear and universal class hierarchy, with every feature carefully defined at the right level of abstraction: “food” at the top, “sandwich” in the middle, and “PB&J” at the bottom.
Instead, our sandwich category is (at least partially) prototype-based, as opposed to rule-based. A sandwich is something that matches the 10,000 examples of things you’ve called sandwiches in the past. And while those past prototypes do share common features that you could abstract out with conscious thought, that’s not how your sandwich classifier actually works. Like an artificial neural net that is trained to classify kitteh versus doggo, you have developed a reliable “is this a sandwich” function based on the behavior of everyone around you, your entire life.
It’s similarly obvious that a hot dog is not a sandwich, because in reality, nobody would point at a hot dog and say “hand me that sandwich”. But when forced to say why, our powers of post-hoc rationalization kick in (a subject that’s so expertly covered in the recent book from Kevin Simler and Robin Hanson, The Elephant In The Brain). Our natural snap judgement is challenged, and our conscious minds grope around for a reason; “why didn’t I categorize a hot dog as a sandwich?”. And the answers come back as cleverly fabricated stories in terms of logical rules, like “sandwiches don’t have seams” or “hot dogs have toppings, not fillings”.
Ultimately, the viral nature of this question stems from confronting the uncomfortable truth that categories are messy; they act like terrible spaghetti code, rather than like elegant mathematical proofs. Sandwich is a category that accrues from a lifetime of seeing things categorized a certain way, with a dash of post-hoc essence-extraction. And when someone challenges us by confronting us with the fact that our post-hoc rules about sandwich definition should theoretically include something we know damn well isn’t a sandwich, that’s funny.
So therein lies the real evidence for the non-sandwich-ness of hot dogs. Because it’s a funny, viral question, we can take that as an indication that the popular intuition is that hot dogs are a separate category. If they weren’t, than asking the question would be met with “meh, they’re sort of sandwiches, but who cares?”
So, we have our answer; if the only “truth” of a category’s correctness is its robustness in a population of humans, then we should expect people to latch on to a category violation that they recognize, but can’t really explain. Ipso facto; it's funny because hot dogs are not sandwiches, and hot dogs are not sandwiches because it’s funny to suggest that they are.
You may now return to your regularly scheduled program of enjoying jokes rather than crushing them to death.
 I’m using the word “category” here in more or less the same sense that Douglas Hofstadter would use it in his works, like Surfaces and Essences. As opposed to, say, the way a mathematician might use it in category theory.
 If you wanted to actually get a vote on the hot dog question, I suspect you’d have to be psychology-experiment-sneaky to get an accurate count, because as soon as you’ve activated this as a funny question, people would take a stance that’s more about their level of contrarian-ness than their actual in-built category boundary; you’d have to do something like flashing pictures of food in various situations, and have people rapidly press a categorization button, or something like that.