Nothing stops anyone from celebrating a stray (or neighboring) dog's birthday. The difference between a dog and a chair in that context is the dog will wag its

Nothing stops anyone from celebrating a stray (or neighboring) dog's birthday. The difference between a dog and a chair in that context is the dog will wag its tail in an expression of happiness if given a birthday treat. The chair won't. So being able to experience happiness may be an indicator of life. Just watch some young squirrels running and jumping over each other this Spring. That's life.