I was a discussion amongst friends about when is a hamburger, a hamburger. We agreed that it was critical to the hamburger state that it remained covered in two buns and had cow meat in the center. But what of the chicken burger? Or is it a chicken sandwich? No one doubts that if you put bacon in a hamburger it still is one, but what if you remove the cow meat, is it still a burger? What of the manner preparation, does it influence its burgerness? What if the bottom bun falls off, still a burger?
 
I realize such deep philosophical could not be responded lightly and so I have submitted them to debate. So I ask you what MUST a burger have to be one, and at what point it no longer is?

a burger must be made of beef and in between two buns
a burger is no longer a burger if its not made out of beef and not between two buns

 A Luther Burger is a hamburger (specifically a bacon cheeseburger), with a grilled glazed donut in place of the bun.  
 

    

when it isn't using ground meat and/or there isn't some sort of layer sandwiching the filling.

When I magically turn it into poop!

When it uses turkey?

" When it uses turkey? "

The term "hamburger" refers directly to the fact that "hamburger meat" is used, all you need for something to be considered a hamburger is a hamburger pattie, at the same time though, the second you remove the hamburger pattie it can no longer be considered a hamburger. Asked and answered.

What's up with all these hamburger threads ? use your imagination and come up with something more original !

When it's ajar.

When it doesn't have meat on it?

When there isnt a hamburger inbetween the bread.

When either the meat or 1 of 2 buns is missing, or both, it is no longer a burger.

When its a KFC double down, no bread = no burger!

A burger is not a burger when it's not bought from a fastfood company.

when you eat the burger patty alone on a plate with a knife and fork in a fast food restaurant 

Open faced,  
 
A MAN CHOOSES PICKLES!

"  A Luther Burger is a hamburger (specifically a bacon cheeseburger), with a grilled glazed donut in place of the bun.  
 

    

 According to legend, the burger was named for and was a favorite (and possibly invention) of singer-songwriter and record producer Luther Vandross. This origin is mentioned in a January 2006 episode of animated series The Boondocks, "The Itis", in which the character Granddad creates an entire restaurant based on the burger (and other soul food). "

when its missing the burger (meat) part of it

hamburger is a type of burger which is a type of sandwich. For a hamburger to be a hamburger it must have ground beef.

It stops being a burger when it no longer has beef or bun. 
No such thing as a chicken burger there chicken sandwiches.

When it leaves home for the first time, enrolls in university and become and mothertrucking MANBURGER.
 

When its in mah tummeh.

As long as it is some form food between two pieces of bread, I'd call it a hamburger. If that's chicken, fish, cow, turkey or even vegetarian options doesn't matter to me.

Gotta go with (ground beef + 2 buns + some kind of condiments).  Buffalo and turkey burgers are perfectly valid as long as they nail the other two criteria.  No meatless vegan trash, or open-faced alternatives will suffice.  Again, if it's missing condiments of some kind it's really nothing more than a grilled meatwad.

i say it needs meat not some veggie stuff and that meat has two be between two things that serve as buns like traditional buns or even donuts like the Luther

I don't really like pickles.

what is a hamburger really ? 
 
no one knows

When the buns are replaced by grilled cheese sandwiches. 

" When the buns are replaced by grilled cheese sandwiches. 

"

A burger must have two buns and a meat patty.