As the development of the society and the process of civilization, people have a better self-awareness and start to address the relationship between humans and the world. Some philosophers such as Singer believe that humans and other animals are morally equal because they are sentient. However, since humans are not perfect, humans have limit understandings of all beings. Indeed, humans can discriminate the pleasure and pain of other animals by observing their behaviors such as puppies are happy when they wave their tails. But humans fail to mentally feel animals’ pleasure and pain. It’s above humans’ awareness. Therefore, it’s not morally right to put humans’ understanding of the world on other animals. They may deserve moral consideration, but not by following humans’ cognitions. In a word, human beings need to evaluate morality based on the essence and common points of all lives, but not just based on humans’ cognitions.