"The Anti-Vivisector does not deny that physiologists must make experiments and even take chances with new methods. He says that they must not seek knowledge by criminal methods, just as they must not make money by criminal methods. He does not object to Galileo dropping cannon balls from the top of the leaning tower of Pisa; but he would object to shoving off two dogs or American tourists."

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...we sacrifice other species to our own not because our own has any objective metaphysical privilege over others, but simply because it is ours. It may be very natural to have this loyalty to our own species, but let us hear no more from the naturalists about the "sentimentality" of anti-vivisectionists. If loyalty to our own species - preference for man simply because we are men - is not sentiment, then what is?

— C. S. Lewis