Are Our Dogs "Accidents of Nature"?

"A really companionable and indispensable dog is an accident of nature. You can't get it by breeding for it, and you can't buy it with money. It just happens along." - E B White, The Care and Training of a Dog

I found the above quote at http://www.i-love-dogs.com/quotes/2.html.

E B White may have known a great deal about pigs, spiders and the Elements of Style, but apparently, he didn't know much about the training capabilities of dogs. "It just happens along"? Geesh, that's like saying a child can raise itself into an ethical, intelligent, self-supporting adult.