How to get beat up in a bar

Psst, wanna to make some quick money? Here's what you do: go down to the local watering hole, strike up a conversation, mention dolphins, and ask the guy if dolphins are fish or mammals.

“They're mammals.”
“Naw, they're fish.”
“Bullshit, dolphins are mammals”
“Put your money where your mouth is. I'll spot you ten bucks they're fish.”
“You're on, sucker.”

Then you show the mark this picture

Dolphin, in front

and this dolphin-fishing website.

Be prepared though, in case he gets down off his bar stool, wraps his belt around his knuckles, spits out his chaw, and proceeds to say “I believe you have possibly committed a fallacy of equivocation.”
Then he beats the shit out of you.

Dolphin, on right

He'll be wrong though.  You didn't bet that ALL dolphins are fish, or that they couldn't be something else too, you only bet that there are fish that are called dolphins, and there are, like that one up there in the picture.You can console yourself with the knowledge that you actually won the bet and he's just a poor sport, as you lie bleeding in the alley. 

C'mon, you didn't really expect a guy to admit he's wrong did you? Voltaire really tried this, y'know, that's where he came up with his motto, in the hospital:

“If you want to argue, first define your terms”

Gnu atheist antallan didn't get the memo.

Uzza, how do you conceptualize a unicorn? Does it have hoofs like a horse’s or like a goat’s? Does it have a tail like a horse’s or like a lions?

But I don’t believe that unicorns exist. So my conception is, I suppose, a kind of quantum superposition of all these states that describe some people’s (historical?) beliefs of what a unicorn looks like. To criticize me for not choosing any single “eigen-conception” (e.g., goat’s hoofs, lion’s tail) is largely irrelevant when unicorns don’t exist! All of them are wrong.

Nobody's criticizing your choice of conceptions, you can think anything you want about unicorns. I would criticize if you made claims about things you don't know anything about. Like say, claiming all the states that other people attribute to unicorns, or god, are wrong when you don't even know what those states are.

You know something doesn't exist, but you don't know what it is. Well, I do. My conception of a unicorn is a backhoe. Being a backhoe is the only necessary state for something to be a unicorn. You say this state, of being a backhoe, describes something that doesn't exist, but see,
backhoes do exist;
and you look like an ass;
because you let me define your term for you.

Backhoe, in trouble

Nnnnnnnnow, you'll probly say I'm crazy, nobody thinks unicorns are like that. Mebbe so, but you didn't specify non-crazy people, you said all the people's beliefs are wrong, whatever they are. You just assumed other people are not crazy, just like you assume they're wrong. Not a safe assumption, pilgrim.

You can change your story and argue that my idea of a unicorn is wrong, but that's a whole different issue. Your claim was that no unicorns exist, no matter how defined. Now that they've been defined, as backhoes, if you keep arguing that backhoes don't exist, you'll be wrong. And stupid.

Ok, that's an extreme case. What state might a non-crazy person come up with? Mariann Webster comes up with: an an animal that looks like a horse and has a straight horn growing from the middle of its forehead. Could somebody claim such a beast exists?

Cage Match!

In this corner, defending his title, Antallan, champion of the claim that (an animal that looks like a horse and has a straight horn growing from the middle of its forehead) doesn't exist.

...aaaaannnnnd.....

In this corner, Unicorn, the challenger from Prato, Italy.

Unicorn, in Italy

Remember the rules: no arguing about what's a unicorn or not, we have to use Mariann's definition, because you didn't have one. Too late now, buddy.

See what happens when you don't listen to Voltaire?