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To address this problem when assessing the capacity of other species to experience pain, argument-by-analogy is used. This is based on the principle that if an animal responds to a stimulus in a similar way to ourselves, it is likely to have had an analogous experience. Dr Chris Sherwin at the University of Bristol used this line of reasoning to question whether invertebrates have the capacity for suffering. He argued that if a pin is stuck in a chimpanzee&#39;s finger and she rapidly withdraws her hand, then argument-by-analogy implies that like humans, she felt pain.
Sherwin, C.M., (2001). Can invertebrates suffer? Or, how robust is argument-by-analogy? Animal Welfare, 10 (supplement): S103-S118Можно еще почитать Elwood, R.W., (2011). Pain and suffering in invertebrates? Institute of Laboratory Animal Resources Journal, 52(2): 175-84