an over-extension of an essential-biological mode of thinking stemming from cognitive development. Paul Bloom of Yale University has stated that "one of the most exciting ideas in cognitive science is the theory that people have a default assumption that things, people and events have invisible essences that make them what they are. Experimental psychologists have argued that essentialism underlies our understanding of the physical and social worlds, and developmental and cross-cultural psychologists have proposed that it is instinctive and universal. We are natural-born essentialists." Scholars suggest that the categorical nature of essentialist thinking predicts the use of stereotypes and can be targeted in the application of stereotype prevention (Bastian & Haslam, 2006). In ethics Classical essentialists claim that some things are wrong in an absolute sense. For example, murder breaks a universal, objective and natural moral law and not merely an advantageous, socially or ethically constructed one. Many modern essentialists claim that right and wrong are moral boundaries that are individually constructed; in other words, things that are ethically right or wrong are actions that the individual deems to be beneficial or harmful, respectively. In biology Before evolution was developed as a scientific theory, there existed an essentialist view of biology that posited all species to be unchanging throughout time. The historian Mary P. Winsor has argued that biologists such as Louis Agassiz in the 19th century believed that taxa such as species and genus were fixed, reflecting the mind of the creator. Some religious opponents of evolution continue to maintain this view of biology. Recent work by historians of systematic biology has, however, cast doubt upon this view of pre-Darwinian thinkers. Winsor, Ron Amundson and Staffan Müller-Wille have each argued that in fact the usual suspects (such as Linnaeus and the Ideal Morphologists) were very far from being essentialists, and it appears that the so-called "essentialism story" (or "myth") in biology is a result of conflating the views expressed by philosophers from Aristotle onwards through to John Stuart Mill and William Whewell in the immediately pre-Darwinian period, using biological examples, with the use of terms in biology like species. Gender essentialism In feminist theory and gender studies, gender essentialism is the attribution of fixed essences to men and women—this idea that men and women are fundamentally different continues to be a matter of contention. Women's essence is assumed to be universal and is generally identified with those characteristics viewed