Paradigm Shifts, Scientific Revolutions and the Moral Justification of Experimentation on Nonhuman Animals

An estimated 70 to 120 million nonhuman animals are killed every year in scientific experiments. l The justifications for the use of nonhuman animals in scientific experiments to benefit humans are based on two conflicting paradigms or models regarding the nature of human and nonhuman animals. This paper will trace the origins of these competing paradigms and the assumptions underlying each of them as they relate to scientific research. According to Thomas Kuhn, in his landmark work The Structure of Scientific Revolutions, when there are two competing and incompatible paradigms, one of them has eventually to give way to the other.2 Scientific revolutions, by their very nature, involve a shift from an old or traditional paradigm to a new paradigm. A paradigm shift, we wiU argue, is presently taking place in tlle biological sciences. The effect of this shift is currently being experienced in the conflict and uncertainty over what policies to adopt regarding the use of nonhuman animals In scientific experiments. 1. The Traditional Paradigm Underlying "Animal" Experimentation