Say Uncle continues to school us all in the ways of dogs. I take to my fainting couch and refuse to believe that Mrs. Wigglebottom does not have a rich interior life. She sighs, Uncle, the most forlorn sighs of… well, forlornness. Doesn’t that prove that she’s not just reacting to her environment, but seeking to impose her will on it? I hope so, because I’ve left her in charge of paying the bills these last few months. I’d hate to think my trust in her has been misplaced.
Tiny Cat Pants 
don’t misunderstand that they don’t attempt to impose their ‘will’ (for lack of a better word – ‘desire’ is probably more appropriate) to an extent. but, by and large, i think they react in a programmed manner to stimuli. E.g., threat = bark, mom is home = excitement, cat in yard = chase, etc.
And my dog is very vocal with grunts, sighs, etc.
Men are very vocal with grunts, sighs, etc., too…is that the same kind of thing?
I think naming a dog Mrs Wigglebottom negates any and all their natural instincts. ;-)
I’m going to have to go with interior life. It’s been awhile since I’ve had a dog, but the last one was definitely capable of invention… she could have ideas. Her ideas may have been constructed from past stimuli (I want to smell Tanglethis, but she’s mad cause I peed on the carpet. However, I know she keeps a basket of laundry, and although I’ve never touched it, I bet the clothes in it smell like her. I think I’ll take out just one sock so she won’t be madder and put my head on it.) but then, how many humans can’t say the same?
Besides, dog brains must be similar to cat brains in complexity, and cats certainly have imagination. Not every cat, of course, but the ones I keep currently do… it’s hilarious to watch a cat at play pretend that she is being chased by the toy mouse she kicks around. I also love to put favored toys in hard-to-reach places and watch the smarter one sit back and figure out how to get it.