It is not merely in terms of logic, metaphysics, and the natural world around us that we use categories in an attempt to predict, explain, manipulate, and understand. We employ and apply categories in ethical and social cognition as well. Categorical misapplications with regard to the natural world can result in failed attempts to predict, explain, understand, or intervene in the course of nature. Categorical misapplications in the social realm can carry an additional burden of ethical mistake and negative social consequences.

There are a range of lessons to be learned here, both regarding the nature of categories – studied here in a realm independent of “nature's joints” – and with regard to social construction and ethical action.

Categorization Errors in Social Cognition: Oversimplification

A major purpose of categorization is simplification. The world around is a complex place, with no event exactly repeated in all particulars and no process repeatable without some variation. Effective cognition and effective action demand that we work with a simplified representation of such a world, in which items, events, and processes are conceptually grouped in terms of categories.

One clear danger in any such categorization is oversimplification: a categorization that is too simple to do justice to the genuine complexity with which we are attempting to deal. That oversimplification can be particularly troublesome when it is complex social realities which we are trying to address.

Consider for example categories very often used in thinking about groups of people in our society, and the ethical emotions we find appropriate for different groups:

• • The homeless.

• • The mentally ill.

• • The drug-addicted.

• • Petty criminals.

We sympathize with the homeless and want to relieve their plight. A similar sympathy seems appropriate with the mentally ill, though the measures to be taken would seem to be very different. With regard to the drug-addicted we may have mixed emotions, particularly in recognizing lives that have been characterized by repeated bad but voluntary choices. In thinking of petty criminals our sympathy may waver or disappear.

What is wrong with this exercise is the illusion that these categories are genuinely distinct. Many people fall into several or all of them. The most extensive survey of the homeless, taken on a single night in 2014, reached the consensus that 45% of the homeless had some form of mental illness, with serious mental illness in an estimated 25% (Torrey 2021).