"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 unfeeling 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."
Dr. Carl Sagan & Dr. Ann Druyan
SHADOWS OF FORGOTTEN ANCESTORS, 1992
Animal Rights FAQ
The Post-Darwinian Transition