Interspecies differences may lead to concluding that substances that are innocuous or beneficial in humans are harmful, and that substances that have… - Deborah Mayo

Arguments to the effect that it is wrong to cause pain and suffering to animals are often rejected by claiming that animals simply do not suffer. … Ironically, it is precisely upon the assumption that animals do suffer from stress, fear, and pain in a manner similar to humans that the validity of much of animal experimentation rests. Few, if any, conditions are studied as widely in animals as are pain, stress, ulcers, fear, and anxiety.

One type of medical research involves ascertaining whether certain pathological conditions in humans can be alleviated or cured by certain drugs. Animals are used as "models" upon which to test these treatments. To do this it is necessary for the animal subject to have the condition in question, and in order to bring this about healthy animals are made sick. … It turns out, however, that the conditions artificially induced have little in common with the naturally occurring diseases in animals (when these exist) and much less in common with the diseases in man.

The error in depicting critics of animal experiments as anti-science becomes clear when one begins to question the extent to which the purported scientific aims of these experiments are actually accomplished. For then it turns out that the experiments and not their critics are unscientific.