In a similar vein as Gab, I propose, that Goofy doesn’t even belong on the list. One of the primary traits all other dogs in the grid share is that they understand Doggish — certainly well enough that Dug and Brian can interpret for and interact with more “traditional” dogs in their own universe. Goofy, if my memory is correct, never seemed to understand Pluto any better than his fellow non-dogs like Mickey and Donald.

Goofy might just be another in Disney’s long line of genetic abominations, and not strictly a cartoon dog.

Overthought: Maybe this (site) is where it came up before, but in the Disney world, if you have clothes, you’re a master and can talk, and if not, you’re a pet. I think it’s much, much creepier that Goofy is totally okay with the subordination and objectification of his fellow dog than Scooby and Scrappy Doo being in the same cartoon.

@Evil: Well, it depends on the episode. Astro sometimes walks on two legs and puts his arm around George’s shoulders, and Astro has worn clothing before. I haven’t seen an episode of The Jetsons for a while, but I too remember him mostly acting like a dog.