The dog is not reflecting on its true nature. If that is true, then it's possible there are many beings, including us, who are not reflecting on their true nature. It shows the meditative power a human actually has. For example, if a parent actually sits down and realizes they'd die for their child no matter what, it would sort of be like the dog realizing how far it would go for a tennis ball. Only a human being can reflect and change, the dog cannot (it's one of the reasons humans fall in love with dogs, they realize the thing is utterly innocent).