Look at the top picture first and notice the little boy in the wheelchair. He is clearly defined as “different” from the other children and is both spatially and psychologically defined by the chair. He is separate from the class and the chair fundamentally defines him. Now look at the bottom picture. The same little boy is on the right in the stripped sweater. The chair does not define his essence.

The basic tenet of psychological essentialism is the idea that humans have a core belief that unobservable essences are causally responsible for the surface features (behaviors) we observe. As such, the world is divided up into essences from which behaviors can be inferred. It’s the belief in an underlying reality or a true nature that cannot be observed.

At its ugliest, essentialism applied to ethnic groups is a form of racism because we assume that all members of a particular group share an unchangeable core reality with respect to physical or intellectual proclivities. It’s a pretty aggressive verbal attack to accuse someone of essentialism – especially in academia. Note what happened to Larry Summers, then President of Harvard, when he suggested that the scarcity of women in science and engineering might be because of gender differences in intrinsic aptitude. There was an outcry of protest and he no longer holds his coveted position. Moreover, if you believe someone’s behavior is governed by an essentialist property then other avenues of inquiry or explanation are eliminated. Why care about other explanations–social, economic, familial, political, educational–when this unseen essentialist quality explains everything.

Psychological essentialism can function as a “placeholder” in that one can believe that a given category possesses an essence without knowing what the essence is. Seen this way essentialism is a reasoning heuristic. But the reasoning is bad reasoning. The essentialist quality is mysterious and unknown and usually evolved as a result of inductive experiences that lead to mostly unjustified generalities.

One of the most common responses to essentialists is to pose a cultural explanation. But that has become problematic because it trades one orthodoxy for another. The essentialization of culture is no different than the essentialization of women or any other category. Women, for example, have been overgeneralized to the private sphere; that is, their domestic duties have been justified by essentialist explanations. They are assumed to be homogeneous. This has sanctioned the economic and sexual exploitation of women along with a host of distorted opinions, discriminatory practices, all known to be old-fashioned sexism.

In response feminist groups have demanded respect for the diversification of women and recognition of cultural differences resulting in categories such as “African Women,” “Muslim Women,” “Western Women,” “Third World Women,” and the like. These new cultural categories represent a homogeneous collection of heterogeneous people.

There is a conundrum in the feminist literature that depends on belief in women sharing certain properties but also seeks diversity and recognition for individuality. The feminists’ widespread rejection of essentialism has threatened to undermine feminist politics.

How legitimate is it to affix the modifier “Islamic” to some noun. Is there such a thing as “Islamic terrorism?” What essence are we drawing on when we refer to “Islamic art,” “Islamic politics,” “Islamic philosophy,” and “Islamic culture?” Do Islam, or Christianity, or Judaism, have an essence? Irfan Khawaja in his article on essentialism and Edward Said’s Orientalism, asked the question “how can one possibly talk about a single essence of Islam when what we see is irreducible variety?” Said goes about the business of claiming an essence for Orientalism while at the same time philosophically challenging essentialism.

In the end, essentialism is truly a psychological phenomenon in that we believe in essences because they are composed of a logic attributable to the “psyche.” The human belief in essences that represent terminal explanations becomes so reductionist that they are soon reduced to nothing.