“Humans — who enslave, castrate, experiment on, and fillet other animals — have had an understandable penchant for pretending animals do not feel pain. A sharp distinction between humans and 'animals' is essential if we are to bend them to our will, make them work for us, wear them, eat them — without any disquieting tinges of guilt or regret. It is unseemly of us, who often behave so unfeelingly toward other animals, to contend that only humans can suffer. The behavior of other animals renders such pretensions specious. They are just too much like us.”

American astronomer, planetary scientist and science communicator

Carl Edward Sagan was an American astronomer, planetary scientist and science communicator. He worked at Harvard as an assistant professor before moving to Cornell University, where he became the David Duncan Professor of Astronomy and Space Sciences and directed the Laboratory for Planetary Studies. Sagan took an active role in the Mariner, Viking and Voyager programs. He also wrote more than 600 scientific papers and articles, along with several popular science books, beginning with The Cosmic Connection. His The Dragons of Eden won the Pulitzer Prize for General Nonfiction.