If it looks like a duck, waddles like a duck, and quacks like a duck, then it probably is a duck!

probably a penguin too

Unless it's a toy duck.

In the general case, not necessarily; even if an entity displays a set of characteristics most typical of one set, if there is a subset of another set whose members also display those characteristics, then the creature is more likely a member of the larger set than the one it is "most typical" of.

There's a statistical/psychological fallacy along those lines, and I can't remember it at the moment.

Is there a larger set of items that looks, waddles, and quacks like a duck?

Good question, Rachel, but even then, as far as we know, the far largest subset is still "duck", so the probability stands :)

I'm a pedant, not a zoologist.

Or is that ornithologist. I don't even know what I'm not.

Look, anything that appears that goes to that much trouble to look that much like a duck clearly has sinister motives. Anything that looks that cut and dried is clearly a trick. Get an axe.

Have I mentioned recently how much Ben Breedlove works to resemble a duck?

The escape clause is the word probably. It might be Ben Breedlove, but what are the odds?

Anyway, Ben looks waddles and quacks like a heart-shaped-plush-pillow breeder to me.

Don't listen to him. I'm harmless.
Quack.

It depends, what language are we programming in again?

It is acting LIKE a duck. Not AS a duck. It could be a mutated monkey.

Or a loon.

I think it's a Platypus.
:)

Hail platypus!

Not in the restaurants I go to. If it's moving at all, it's probably either another human or some animal which should be removed at once to the nearest farmyard. In my experience, duck is a meat usually served with plum sauce.

I can recognise a pigeon - after that all birds are penguins as far as I'm concerned.

The claim holds only under non-typechecked languages like Smalltalk.

Lua, Python, et al are not languages any more than English is; they are toys with the occasional useful application.