TCS Daily


Categorical Errors

By Robert McHenry - August 25, 2006 12:00 AM

Pluto is no longer a planet. That Pluto was a planet turns out to have been a matter of great public interest, if the media coverage of its demotion is a fair indication. It was on the front page of my local newspaper yesterday (of course, so was an article about the inane television program "Survivor" -- something about racing teams, or racial teams, or whatever), and a headline in today's edition refers to "beloved Pluto." It's been discussed over and over on television news, and, of course, it's been blogged.

It's hard to divine the source of this fascination. In part (like the "Survivor" article) it simply reflects the judgment of a lot of news editors. Maybe the pause in the shooting war in Lebanon left them with time and space to kill. Maybe it's just August and the traditional journalistic silly season, brought on, as we all know, by the annual rising of Unsirius, the Dog-and-Pony Star.

But in part I suspect that the interest is genuine and stems from a common confusion of thought, the error of believing that categories are real. This was one of the great intellectual battles of medieval philosophy, that between realism and nominalism. The realists held that "universals" such as categories had an independent existence, apart from and in some sense superior to actual objects. Nominalists held that universals are only mental constructs. By and large, the nominalists won the argument but little more. Like the flatness of the Earth, realism crops up in our uncritical thinking still.

A realist of this kind is apt to assume that "planet" is a natural kind, that it's something with certain essential characteristics and that the properly equipped observer just knows one when he sees it. A tree is a tree, a frog is a frog, a planet is a planet, and a good cigar is a smoke. End of story. And so, when it is suggested for some reason that Object X, which we always knew to be a tree or a frog or a planet, isn't one, the suspicion arises that there's something, well, suspicious going on. Whaddya mean Pluto isn't a planet? Of course it is. Always was, always will be.

So what happened to Pluto? How has it changed, that its status should be questioned and people all over the world apparently be concerned? In fact, Pluto has not changed at all. It's still the undersized, slightly oddball object it always was -- undersized and oddball, that is, in comparison with some characteristics of some other objects that we accept as indisputably planets.

I learned how to think about categories from John M. Ellis: (I paraphrase) A category is not a collection of like things; it is a collection of unlike things that we choose to consider like for some particular purpose. In other words, categories are tools for thinking, made and open to remaking by humans.

Look at it this way: There is this star, and around it revolve a huge number of objects. Four of those objects are significantly larger than any others, so it seems natural to think of them as members of a category, perhaps one labeled "really big things revolving around the Sun." The question then arises, are there any other objects that belong in this category? How about Earth, which is the next biggest object? Of course; no question that we belong with the big kids. Venus is just a bit smaller, so sure, Venus. And so on. (This sketch is not historical, by the way. The planets [wanderers] for the Greeks were those celestial objects that moved against the background of fixed stars.) So how far down do you go with this category? Bear in mind that the objects under consideration range all the way down to dust particles and, beyond those, to random molecules and atoms. You have to stop somewhere, and where you stop depends entirely upon how you intend to use this category -- to identify objects that arose through a common process, for example.

When the definition of "planet" began to seem more porous than was useful -- meaning that it was loose enough that it could arguably apply to some objects that it was inconvenient in other ways to think of in the same category, like the asteroid Ceres or the faraway object 2003 UB313 -- it was time to reconsider the definition. That is all that the International Astronomical Union has done. The discussion of a new definition revolved (get it? revolved?) around the question of what the purpose of the definition was -- what objects and kinds of object do we wish to distinguish by this term "planet" and why? What kind of definition, incorporating what sorts of criteria, is meaningful for our work? In the end, by a large margin, a new definition that happens to exclude Pluto was adopted. Pluto is now the first citizen of a new category called "dwarf planet."

My newspaper tells me that this is a big deal in part because so many people have memorized the list of planets and now will apparently have to devote considerable processing power to remembering to delete the last one. Also, solar system mobiles will have to be redesigned. Textbooks have to be rewritten (ignoring the fact that textbooks are "rewritten" whether they need it or not, to keep publishers' revenues up). None of this explains page-one treatment.

There were questions about Pluto almost from the day Clyde Tombaugh discovered it in 1930. It didn't bother Tombaugh, it seems. His widow quotes him as having said before he died in 1997, "It's there. Whatever it is. It is there." That's the simple fact; the rest is just name-calling.

Robert McHenry is Former Editor in Chief, the Encyclopædia Britannica, and author of How to Know (Booklocker.com, 2004). He wrote recently about Ahmadinejad's blog. He is a TCS Daily Contributing Editor.

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22 Comments

Categorical Errors like Race
"But in part I suspect that the interest is genuine and stems from a common confusion of thought, the error of believing that categories are real."

Absolutely true. But perhaps the biggest category with which people have confusing ideas is race. Genetically speaking, every single human being on the planet -- whether an Australian Aboriginee, a Native American, or a Sweedish Caucasian -- all belong to the same race. Consequently when most people speak of "race" what they're really speaking of is culture, bounded by superficial cosmetic traits.

For example, Tramm Hudson recently remarked that "I grew up in Alabama. I understand, uh, I know from experience, that blacks are not the greatest swimmers or may not even know how to swim." Now what Tramm was trying to say (I hope) was that black Alabamans from his youth -- the ones we can in contact with -- were not great swimmers because they did not have swimming lessons and/or many opportunities to swim.

In terms of genetics, there's nothing to prevent any healthy human from being a competent swimmer. However the relative importance sub-cultures place of various ideas and activites can affect the number and quality of swimmers it produces. Yet cultures, particularly sub-cultures, can change very quickly and "weaknessess" evident in one generation can laragely disappear by the next.

So when speaking of artificial differences between "racial" cultures, it pays to be precise and open-minded.

The Daily Planet
Pluto had a good long run .Discovered around the year of Captain Bluto's cartoon debut, the eccentric body's nototiety outlived the popeyed John Belushi, and outlasted the fame of George's Star, AKA Uranus.

As Uranus was on the books,but unrecognized as a planet from 1690 til 1781, Lord knows how many nondescript blue dots on plates in existing observatory archives are in fact Kuiper Belt objects awaiting their 15 minutes of siderial fame.

Such newspapers as feature horoscopes should accompnany each by an image of whichever of these underreported heavenly bodies is at its zenith at the time , the right to name it being auctioned off for the benefit of the Fund for Decrepit Astrologers.

Maybe not the final say
If we're making up categories in which we can put all the various objects found inside our solar system, we should note that several of the moons orbiting the giant gas planets are indeed rocky planets of about the size of Mercury. Should they not be thought of as planets?

For that matter, why use a single word to describe two very different kinds of objects? The small rocky planets are about as diferent as any object could be from the gas giants like Jupiter or Saturn. Those "planets" are in fact more akin to their slightly larger brethren, the brown dwarves. Which are now considered to be sort of, almost stars.

I think the schema needs more work.

My skin produces Vitamin D, but Jesse Jackson's skin does not.
There are very real biological differences between the races. There is the susceptability to the effects of alcohol or sickle-cell anemia. There are height and weight differences (tell me Samoans aren't larger and fatter on average than the M'Buti pygmies.) Race has a very real meaning, and the differences are stark and genetically verifiable.

For a few more differences, read The Bell Curve. Statistics frequently lie, but it is hard to lie with that much data to support you.

They actually account for your objections with the new definition.
The description is a little arcane if you want to get in to details, but the International Astronomical Union basically says that a planet meets these characteristics:

1) It is a body orbiting a sun, and not another body.

2) It is massive enough that its own gravity will shape it in to a sphere.

The link is below. If you really want to know the details, they are all there.

http://www.space.com/scienceastronomy/060816_planet_resolution.html

Dark Skin Produces Vitamin D
"There are very real biological differences between the races."

If you really believe that, then you should have no problems findin the answers to these very simple questions:

1. How many distinct genetic currently races exist in the global human population?

2. What are the names of these genetic groups?

3. Which genetic markers or attributes define the boundaries of these genetic groups?

4. What kind(s) of genetic tests can accurately determine a given human being's place within one group or another?

Now you can search the world over and you will not find any answers based on genetic research -- multiple genetically distinct races just do no exist. The "races" we know of today are as made-up as the state boundaries on a map.

realism v. nominalism
A friend of mine writes privately to propose a solution to the dispute, a via tertia:


"I admit I have long been a waffler on the realism-nominalism thing. It’s my considered judgment that categories already in currency when I grew to consciousness are real, whereas more recent coinages are mere human constructs. Take baseball. We have the American League and the National League. They exist and always have. They are independent of our volition. We could no more wish them away than we could the Rock of Gibraltar. Or Pluto, for that matter. They are the handiwork of God (whether or not she exists is immaterial).


"Divisions, on the other hands, are human abstractions, spurious administrative conveniences created by Man in his boundless hubris to deal with an ungainly number of teams and the expansion of Major League Baseball to regions of the country where it was never meant to be played -- i.e., anywhere west of Kansas City or south of Cincinnati. (I come by this prejudice naturally. One my most vivid childhood memories was the emotional reaction of my normally reserved, Brooklyn-bred mother when the Dodgers left town.)"

I have very wise friends.

Vitamins and skin.
Dark skin is more effective at preventing the destruction of folate (vitamin B,) but does not produce anywhere near as much vitamin D as white skin because it does not let through enough sunlight.

http://en.wikipedia.org/wiki/Skin_color

Are you denying that race exists? I am not a geneticist, so I will not even attempt to answer your questions. However, I will claim denying that different races exist is like denying the existence of different breeds of dogs because they are all four legged critters with teeth. That may be true, but they are very different critters. I think the problem that you might have is in the definiton of race, so let's hear how you define it before we move forward. I will define it as: A population of people visibly and genetically distinguishable from another population of people on the basis of physical characteristics.

Genetics for Dummies
"I am not a geneticist, so I will not even attempt to answer your questions."

You don't need to be a geneticist to use Google (or a library for that matter). There should be plenty of available information available from hundreds of reputable science sites -- if there really were more than one genetically distinct races of humans.

But there aren't, so of course you won't find any answers.

Do yourself a favor and read up on basic genetics -- it will save you from making further obviously false scientific claims.

http://www.amazon.com/gp/product/0764595547/
102-4932193-1092961?v=glance&n=283155

Why should I spend time searching Google to correct a statement that is so obviously false?
There are not different species of humans. We are all Homo sapiens. You seem to be referring to race as meaning a different species, but since you refuse to define terms I cannot even tell what the heck you are trying to suggest.

Blacks have a much higher susceptability to sickle-cell anemia than other races. That trait is genetic. So is the tendenc for Asians to be highly susceptible to alcohol. So is the amount and type of pigmentation in the skin. Skin pigmentation and genetic predisposition are not social constructs, they are FACTS.

You are the one making the extraordinary claim here. Prove to me that Blacks on the whole do NOT differ from Whites on the whole in their susceptability to sickle-cell anemia. Prove to me that Christopher Walken's pasty pale face belongs to the same race as Kofi Annan. Once you have done that, I will accept that race is a fake category.

It's not a "Black" or "White" world
The point is, YOU CAN NOT GENETICALLY DETERMINE who is a member of the "black" race or the "white" race. In fact, you CAN NOT even provide a simple GENETIC DEFINITION of what constitutes a "black" or "white" race.

Sickle Cell Anemia
UCSF Medical Center, 2006

An estimated 70,000 people in the United States have sickle cell disease and 1,000 babies each year are born with the condition. It affects primarily people of African descent as well as fewer numbers of those of PORTUGESE, SPANISH, FRENCH CORSICAN, SARDINIAN, ITALIAN, GREEK & TURKISH descent. The disease also appears in Cypriots and those from Middle Eastern countries and Asia.

http://www.ucsfhealth.org/childrens/medical_services/cancer/sickle/index.html

-----------------------

Genetics and race: Researchers explore why rates of diseases vary from one population to another
Pittsburgh Post-Gazette, May 7, 2002

...Even the most obvious distinguishing factor -- skin color -- can vary enormously within a race, said Joseph L. Graves Jr., an evolutionary biologist at Arizona State University West in Phoenix. And the dark skin of a sub-Saharan African is not unlike the dark skin of a Caucasoid in India, added Graves, author of a 2001 book, "The Emperor's New Clothes: Biological Theories of Race at the Millenium."

That's why most scientists say RACE IS A SOCIAL CONSTRUCT, NOT A BIOLOGICAL ONE. In other words, social rules determine what races are and what they mean.

For instance, someone is commonly considered "black" if he has one black parent and one white parent, or even if he just has one black grandparent. From a biological standpoint, however, there is no logic for such labelling.

If race has a bearing on health, it may simply be as a marker for the geographic origins of certain populations. In the Eastern Hemisphere, where humans have lived for at least 2 million years, differences that developed in skin color were closely correlated with latitude and, thus, exposure to sunlight. (The same pattern is not apparent in the Western Hemisphere, where humans migrated only about 35,000 years ago).

Sickle cell anemia, most closely identified in the United States with black Americans, is OFTEN FOUND IN AFRICAN AND MEDITERRANEAN PEOPLES, Ferrell noted, apparently because that GENETIC MUTATION OFFERED AN ADVANTAVE IN BATTLING MALARIA endemic to those areas. Sickle cell anemia is rarely seen in descendants of people from northern Europe, where malaria is absent...

http://www.post-gazette.com/healthscience/20020507hgene0507p3.asp

Define "Race"
I appreciate that whether a child with parents of different races is considered Black, White, Mulatto, etc. is not a genetic question. I also appreciate the fact that genetic markers for things like sickle cell anemia occur in many different races. However, there are still Black people and White people. Those with undilluted African or Western European ancestry are going to be Black and White respectively. There are variations within all of the categories, true. However, I am not socially constructing the fact that my Asian neighbor has a different balance of pigment in his skin, as does everyone else in his family, and most natives to his country of origin. Asian is a descriptor that can be applied to groups as different as the Japanese and Hmong tribesmen prior to the Vietnam War. Black is a term that applies to Nigerians as well as African-Americans. White applies to Irishmen and Russians. Cherokee, Iroquois, Mohawk, are all referred to as Indians. Broad categories include a lot of wiggle room. No doubt, some of the boundaries between races are not very clearly drawn. However, to say that they are made up is simply to be blind.

The Human Genome Project -- No Races
"There are still Black people and White people."

In case you hadn't noticed, there are also
* short people and tall people
* broad-shouldered people and narrow-shouldered people
* straight-haired people and curly-haired people,
...etc., none of which constitutes a genetic boundary like your imaginary definition of race. What you call a "black" person is completely arbitrary, and varies from culture to culture -- like apartheid South Africa with its dozen or more racial distinctions.


J. Craig Venter, Ph.D., President and Chief Scientific Officer, Celera Genomics Remarks at the Human Genome Announcement

The White House -- June 26, 2000

Today, June 26, 2000 marks an historic point in the 100,000-year record of humanity. We are announcing today that for the first time our species can read the chemical letters of its genetic code. At 12:30 p.m. today, in a joint press conference with the public genome effort, Celera Genomics will describe the first assembly of the human genetic code from the whole genome shotgun sequencing method...

The method used by Celera has determined the genetic code of five individuals. We have sequenced from the genomes of three females and two males who have identified themselves as Hispanic, Asian, Caucasian, or African American. We did this initial sampling, not in an exclusionary way, but out of respect for the diversity that is America, and to help illustrate that THE CONCEPT OF RACE HAS NO GENETIC OR SCIENTIFIC BASIS. In the five Celera genomes there is no way to tell one ethnicity from another. Society and medicine treats us all as members of populations, whereas as individuals we are all unique and population statistics do not apply.

http://www.celera.com/celera/pr_1056647999

races
I suspect that if we used the same standard on humans that are routinely used in the animal world, humanity would have to be divided up into several hundred different species.

Tiny differences, differences that many times can't even be seen by the untrained eye, are often enough to get an animal declared a new species. Small differences in shading of the coat. Eyes just a little bit bigger. Size bigger, smaller, whatever.

One Human Race -- Many More Mammals
Actually, you have the wrong. Humanity would stay as one group, but other mammals would require further division:

Speciation in Mammals and the Genetic Species Concept
by Robert J. Baker & Robert D. Bradley
Journal of Mammalogy, 87(4):643–662, 2006

We define a genetic species as a group of genetically compatible interbreeding natural populations that is genetically isolated from other such groups. This focus on genetic isolation rather than reproductive isolation distinguishes the Genetic Species Concept from the Biological Species Concept. Recognition of SPECIES THAT ARE GENETICALLY ISOLATED (but not reproductively isolated) results in an enhanced understanding of biodiversity and the nature of speciation as well as speciation-based issues and evolution of mammals.

...Using cytochrome-b data from sister species of mammals recognized by classical morphological studies, we estimated the number of phylogroups that exist within mammalian species and hypothesize that there will be MORE THAN 2,000 CURRENTLY UNRECOGNIZED SPECIES OF MAMMALS. Such an UNDERESTIMATION significantly affects conclusions on the nature of speciation in mammals, barriers associated with evolution of genetic isolation, estimates of biodiversity, design of conservation initiatives, zoonoses, and so on. A paradigm shift relative to this and other speciation-based issues will be needed. Data that will be effective in detecting these "morphologically cryptic genetic species" are genetic, especially DNA-sequence data...

Implications of the Genetic Species Concept to higher zoological taxa -- If the hypothesis of Wilson et al. (1975) and Fitzpatrick (2004) that MAMMALS EVOLVE HYBRID STERILITY FASTER than do other vertebrates through genetic divergence as proposed in the BDM model is true, then there may be more rapid speciation in mammals than in other vertebrate groups. Such a difference would be compatible with Patterson’s (2000) observation concerning the rate of descriptions of new species of mammals versus birds. Nonetheless, birds, amphibians, reptiles, and fishes will likely have a pattern of underestimation adjusted for the rate of evolution of hybrid sterility and events that cause allopatric populations, relative to that observed for mammals (Avise and Walker 1999). For invertebrate taxa, because they have been studied less intensively than mammals and because generation time may be much shorter resulting in a faster rate of genetic evolution, which can result in genetic isolation, we hypothesize that the underestimation of biodiversity is significantly greater than for mammals.

http://www.allenpress.com/pdf/mamm-87-04-24_643..662.pdf

Up until 100 years ago, we were isolated.
...

1906 Isolation?
"Up until 100 years ago, we were isolated."

Okay, I'll bite -- What genetically distinct groups were isolated from one another prior to 1906?

with the exception of small groups
Europeans, Asians, Africans,

Travel was ramping up in the early part of that century, but it didn't take off until after WWII.

Fantasy Leagues
"Travel was ramping up in the early part of that century, but it didn't take off until after WWII."

You base your argument on two points that are easy to refute:

1) Each geograpical region was "genetically pure" -- for example, that Moors were not in Spain, Italians were not in China, Germans were not in South Africa, etc.

2) Each "genetically pure" being only mated with other members of the same genetically pure race.

You do know that makes you a believer in Adloph Hitler's garbage?

you really get yourself worked up in a lather whenever someone disagrees with you
They don't have to be genetically pure for the theory to work, they just have to breed true. IE, light skinned people have light skinned babies. Blue eyed people have blue eyed babies.

If two chinese people make a baby, does it look chinese or european?

If two hotentots have a baby, does it look like a hotentot or a native american?

My point was to show how utterly silly the whole concept of species has become.
Two populations of squirells, living on two mountain tops, less than 10 miles apart. Because one has ears that are slightly darker than the other, it's declared a new species.
Yet two groups of humans, one light skinned, light color hair, blue eyes, averaging 6 feet tall, is the same "species" as another group that is dark skinned, dark haired, dark eyes and averaging 4 feet tall.

The whole concept of species makes no sense.

Scientific Accuracy
"They don't have to be genetically pure for the theory to work, they just have to breed true."

Yes they do. They have to have to be genetically (not reproductively) isolated. In other words, you should be able to genetically discern the boundaries that seperate species -- or in this case "races." But as has already been made abundantly clear no such genetic distinction exists.

J. Craig Venter, Ph.D., President and Chief Scientific Officer, Celera Genomics Remarks at the Human Genome Announcement

The White House -- June 26, 2000

Today, June 26, 2000 marks an historic point in the 100,000-year record of humanity. We are announcing today that for the first time our species can read the chemical letters of its genetic code. At 12:30 p.m. today, in a joint press conference with the public genome effort, Celera Genomics will describe the first assembly of the human genetic code from the whole genome shotgun sequencing method...

The method used by Celera has determined the genetic code of five individuals. We have sequenced from the genomes of three females and two males who have identified themselves as Hispanic, Asian, Caucasian, or African American. We did this initial sampling, not in an exclusionary way, but out of respect for the diversity that is America, and to help illustrate that THE CONCEPT OF RACE HAS NO GENETIC OR SCIENTIFIC BASIS. In the five Celera genomes there is no way to tell one ethnicity from another. Society and medicine treats us all as members of populations, whereas as individuals we are all unique and population statistics do not apply.

http://www.celera.com/celera/pr_1056647999

it would be nice if you demonstrated some
"In other words, you should be able to genetically discern the boundaries that seperate species -- or in this case "races." But as has already been made abundantly clear no such genetic distinction exists."

There isn't today, but there used to be. If squirrels had developed modern forms of transportation, I'm quite sure that the example I cited earlier would have no longer been "genetically distinct" either.

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