I hear this particular logical misnomer so often these days that it's practically become a cliche'. I've heard it from stand-up comedians, radio hosts, and dozens of times in personal conversations. You've probably heard it yourself. You might have even been guilty of proliferating it. Here's what happens: You're talking to someone about a movie that contains science fiction or other fantastical elements in its concept. You point out an inconsistency in the plot, or some unrealistic detail of the story that bears no connection to the fantastic element involved in the story's basic concept, and what is the retort of the person you're debating this point with? It's usually some variant of "There's talking dogs in this movie, and you're complaining about...", etc. This is usually said with a tone so heavily laced with snarkiness that it even comes across in the tone-deaf world of internet communication, where we have to qualify even the mildly rudest jokes with smiley faces.
And yet, the person is completely wrong. Making a movie about talking dogs isn't a free pass to throw logic and sense out the window. Such a movie simply postulates the existence of another world, one in which dogs talk. Aside from this conceit, as ridiculous and scientifically untenable though it may be, the movie is still under an obligation to follow certain rules. 1.) It must establish the difference between its world and our own and follow this difference with consistency. If the dogs talk but behave otherwise like normal dogs in every other respect in the first act, they can't be performing brain surgery in the third. 2.) It can not break consistency with other details of its world that it shares in common with our own, without accounting for these differences. You can't move Christmas to April 15th without explaining why or how the change is a consequence of dogs talking. Suppose your story has a subplot about a secret society of mailmen. Without further explanation, this subplot would simply leave the audience perplexed. But if this development is explained by the fact that mailmen are the only ones who can hear the dogs talk, then everyone's on board. Of course, rule 1 comes into play here again. If you establish that only mailmen can hear the dogs talk, you can't have little Billy hear them talk later without accounting for it. 3.) The fantastical conceit of your story isn't a giant rug to sweep plot holes under. Just because your movie has talking dogs, that doesn't mean that Mr. Smith can break his leg in one scene and then be playing basketball in the next.
Of course, I'm using the talking dog example precisely because of the absurdity of it. A movie like that, you could cut it a certain amount of slack because it's clearly a comedy, but the leeway isn't unlimited. Besides, the "Talking Dog Defense" is used for all kinds of stories. It rears it's ugly head when discussing stories with elements that range from everything from aliens to zoos for dinosaurs. Pointing out the logical fallacy involved seems almost too obvious to be worthy of mentioning, but since so many people routinely resort to this argument, apparently it needs to be said. Most people are aware of the literary concept of suspension of disbelief, but they don't know how to discriminately apply it. They treat it like a magic screwdriver in their toolbox of artistic appreciation, and they think it can fix anything. You show them a loose tile that needs re-grouting, and up they pop with the screwdriver.
If you get what I'm saying, feel free to use the phrase. I'm hoping it catches on. The next time you're debating a plot hole in a sci-fi movie with your friend, and you point out that the corporate espionage sub-plot didn't make sense and they say, "You expect a movie about robot armies from the future to make sense?", tell them that they're using the "Talking Dog Defense." When they ask what that is, send them here. Tell them to click on the ads and order a few recommended Amazon products while they're here. I'd feel a lot better making money off of your belligerent friends.
