Authors:

...the nervous systems of other animals were not artificially constructed - as a robot might be artificially constructed - to mimic the pain behavior of humans. A capacity to feel pain obviously enhances a species' prospects of survival...it is surely unreasonable to suppose that nervous systems that are virtually identical physiologically, have a common origin and a common evolutionary function, and result in similar forms of behavior in similar circumstances should actually operate in an entirely different manner on the level of subjective feelings.

...the nervous systems of other animals were not artificially constructed - as a robot might be artificially constructed - to mimic the pain behavior of humans. A capacity to feel pain obviously enhances a species'