He didn't say better, he said different. Sentience, I think exists at all levels of intelligence with varying levels of comprehension. I think dogs are self aware, but have a harder time than humans converting short term memories to long term memories. Otherwise, I think they have the same self-awareness and mental intelligence as a 3 year old human child. They can have a broad vocabulary at that point, they have definite likes and dislikes and certainly have feelings of loss or fulfillment. If you can't see this with dogs, I seriously doubt humanity will ever be able to connect with any other non primate based animal. Sentience has long been thought to be something that only humans possessed. I think that's his point.