The issue of animal testing is one of the more difficult ones within the animal welfare movement. With our hearth we would call for the abolition of animal testing, though with our brains we know it is sometimes necessary. In this respect animal testing differs from other animal welfare topics.
Factory farming could easily be out-phased, as people can perfectly live on a vegetarian diet. Blood sports such as hunting or bull-fighting can be outlawed immediately.
Though many medical treatments would not exist without animal testing, it does not mean animal testing is unproblematic. Once we accept the premise that it is wrong to inflict harm upon humans and animals, it will be clear that animal testing is a problem.
Since it is inherent to animal testing that harm is inflicted upon animals, such experiments require a very strong justification. Mere curiosity is no valid reason to harm animals.
It follows that alternatives for animal testing should be pursued as much as is possible. Possible alternatives are for instance: cell and tissue culture, computer simulations, fungal models and organs-on-chips. In the short run animal testing will be required to develop reliable alternatives, but in the long run they will reduce the amount of experiments on animals.
As a general rule animal testing should be prohibited, unless there is a severe interest for human or animal welfare which could justify such experiments. And such experiment could only be allowed if the researchers can demonstrate that there is no viable alternative.
There should be a balance between the amount of harm inflicted and the interests served by any experiment. If much harm would be inflicted only for limited interests, permission should be denied. It should be clear that cosmetics does not justify the infliction of harm upon animals.
Further all experiments on apes should be completely prohibited.
One should notice that the most vocal advocates of animal testing are not the scientists who conduct these experiments, but those who earn their living with providing the animals and related equipment. These are the ones with the least interest to develop alternatives for animal testing .
We believe that the results of animal testing in the past, does not justify future infliction of harm upon animals. In the past there were little if any alternative for animal testing and hence animal testing could be justified more easily.
 See Peter Singer’s 1975 book Animal Liberation.