" Sentience is not an end in itself. It is a means to the end of staying alive. Sentient beings use sensations of pain and suffering to escape situations that threaten their lives and sensations of pleasure to pursue situations that enhance their lives. Just as humans will often endure excruciating pain in order to remain alive, animals will often not only endure but inflict on themselves excruciating pain—as when gnawing off a paw caught in a trap—in order to live. Sentience is what evolution has produced in order to ensure the survival of certain complex organisms. To claim that a being who has evolved to develop a consciousness of pain and pleasure has no interest in remaining alive is to say that conscious beings have no interest in remaining conscious, a most peculiar position to take. "

― Gary L. Francione , Animals as Persons: Essays on the Abolition of Animal Exploitation