One of the most pervasive, if unstated, notions controlling our thought and discourse today is that of essentialism.
The standard and most reasonable definition of essentialism is hardly objectionable:
"In philosophy, essentialism is a belief and practice centered on a philosophical claim, that, for any specific kind of entity, it is at least theoretically possible to specify a finite list of characteristics - all of which any entity must have to belong to the group defined. A member of a specific kind of entity may possess other characteristics that are neither needed to establish its membership nor preclude its member-ship. It should be noted that essences do not simply reflect ways of grouping objects; essences must result in properties of the object."
The problem is that often essentialism is transformed into the idea that everything belongs to a category, and that once we have placed anything - and anybody - in their category, we have completely and absolutely described all there is to know about that thing.
When examined openly, rationally, critically, this last idea falls flat on its face. That is why it is so often unstated. It is not thought through consciously, but assumed without explicit argument. And it is the grounding justification for many actions, discussions, and policies that continue to due tremendous damage.
The classical example of essentialist thinking is straight from the originator of essentialism, Plato. He is the one who talked of Ideal Forms as being the only true, real things, and said that the actual objects that surround is in the real world are but imperfect reflections of these Forms.
The example is a chair. All chairs are but reflections of the True Chair, which is an Ideal Form, or Perfect Image, of Chairness.
One has only to examine, though, chairs themselves to see how ridiculous this notion is. Think of the many different things people use to sit on, including stools, benches, beanbags, inflated balls, rocks, shelves, nooks, window sills, whatever.
By saying that chair is not a simple and complete description of what we sit on, I am not saying that chairs do not exist, or that the word does not have utility. That is an example of one subset of essentialism, which is the idea that either a statement, or its negative, must be true. The real world, however, is more complex than that, and in the real world, both, neither, or entirely other things, are perfectly capable of being true all at once.
There are no clear dividing lines between chair-things and non-chair things. But that does not mean there are no chairs, or that either the idea or the word has no value. Yet often in political arguments exactly this logic is used as if it were unassailable.
Is that clear and understood? If so, we can continue.
To people.
To life.
One reason natural selection and evolution are difficult to accept for some people is that it rejects essentialism's description of living things.
David Quammen talks about this conflict between Darwin's ideas on natural selection and the traditional thinking he replaced in Quammen's recent biography, The Reluctant Mr. Darwin.
"Behind the Paleyite natural theology lay even deeper and older forms of conventional belief, such as essentialism, the notion that reality is undergirded by a finite number of `natural kinds,' the essential pattern or archetypes of entities seen in the world. This one goes back to Plato. Following his influence, essentialists held that these natural kinds are discrete and immutable, and that physical objects are merely their inexact manifestations. Geometric shapes, for instance, were thought of as natural kinds - triangles being always three-sided, various in their minor characteristics (equilateral, isosceles, scalene) and forever distinct from rectangles or octagons. Inorganic elements were another example - iron being always iron, and lead always lead unless some alchemist found a magical way of turning it into gold. Animal and plant species were also considered natural kinds, rigidly demarcated and unchangeable, though individual dogs or chickens might be various within their hard-sided categories. The essential form of a species, according to this view, is more fundamental and durable than the individuals embodying it at a given time. That's what William Whewell meant when, in 1837, he wrote emphatically: `Species have a real existence in nature, and a transition from one to another does not exist.' To believe otherwise was to reject an assumption that was interwoven with ecclesiastic teachings and ideas of civil order."
This is still the argument being used by creationists (now calling themselves advocates of "Intelligent Design") today. They say that there is variation within "natural kinds," but not between them. But what are the boundaries between these "kinds"? Are insects a "kind"? Are arthropods? How about butterflies?
There are those for whom the natural world is not truly real, and they must imbue all of nature with their categories. Thus, each species of animal or plant is specific, distinct, and clearly divided from others. Darwin and those who understand and have extended his ideas know better. Darwin himself talked of finches outside his window, who would be able to interbreed with their co-specific finches in the area. Those finches in turn would interbreed with finches near them. None of these birds are exactly alike; they are simply enough alike to interbreed, and to be called by us by one name. But they will differ, and eventually they will be far enough away, and different enough in structure and habit, that the original finch outside our window cannot interbreed with them. There is no clear, specific boundary between these birds, and perhaps we will even call them by the same name. But, according to the definition of species that biologists currently use, they are not the same.
The conflict between evolution and essentialism is well understood in the rational, professional world:
"Before evolution was developed as a viable scientific theory, there existed an essentialist view of biology that posited all species to be unchanging throughout time. These ideas were accepted dogmatically by the scholastic theologians of the Middle Ages as derivatives of Aristotelian ideals. Some religious opponents of evolution continue to maintain this view of biology."
Indeed, Darwin's most massive contribution to human thought was not to provide the grand, grounding idea that guides all biological research and technology up to the present day. It was to change the way we think about life, the universe, and everything. Even each other. "He helped us understand the whole physical universe as a realm of concrete contingencies, not imperfectly represented ideals."
All of the above, however, is simply a way of introducing the essentialist way of thinking and its consequences, in order to properly discuss the field in which essentialist thinking does the most damage.
Politics.
Putting people and things in simple categories makes life easier. It is easier to talk about and think about people as members of a group or tribe. It is easier to ignore or denigrate them. And way far easier to kill them.
Think about the way we deal with the people in other countries. We get confused when we learn that the people in Iraq - or any other country, for that matter, but we'll deal with the example that's in the headlines - do not think of themselves as simply Iraqi. They have other identities. They are Sunni or Shiia, Kurdish, Chaldean, Turkoman, Marsh Arab. They are middle class professionals, rural tribesmen, Ba'athist secularists.
The problem is that once we start slicing and dicing populations this way, it's pretty hard to know when to stop. Which is why it's a bad idea to make political identity and rights dependent on tribal identity; the American ideal is that rights and identity belong to everyone equally. What's wrong with that?
Maybe what's wrong is that other people don't deserve the rights and consideration Americans do. After all, they're foreigners.