This month's Scientific American devotes twenty pages to articles on diversity in science—the shameful lack thereof, and what can be done about it. One piece is a kind of confessional by a Lockheed Martin engineer who quickly moved into management and found that as she chose staff from widely varying backgrounds, the quality of her group's work increased. Other articles cite social-science studies that show diverse organizations are not only more socially just; they do better science and engineering too. The reader of these paeans to diversity could not be blamed for taking away the impression that diversity is like goodness: you simply can't have too much of it. Is that true? Or are there limits to diversity?
What does diversity mean? It has both an objective aspect, and a subjective or political aspect. In the strict sense of diversity meaning merely "difference," one can objectively measure diversity in genetic makeup, diversity in hair color, or diversity in virtually any other measurable characteristic that a group of things or people has. This scientific aspect allows statisticians to crank out reams of charts showing the degree of gender diversity in the number of Ph. D.'s granted, ethnic diversity in hiring practices, and so on. So in this scientific sense, diversity is a quantifiable, measurable thing.
But when we ask what kinds of diversity are significant in the sense addressed by the Scientific American authors, the list narrows to political and cultural hot-button matters: gender, race, socioeconomic status, ethnicity, sexual orientation, and so on. Scientists and engineers must deal with these matters not as mythical objective professionals, but as human beings. And in so doing, the issue becomes an ethical, political, and even philosophical one.
The idea of virtue is not a scientific concept, but it is one of the best ways to describe a certain class of characteristics involving choice, as Aristotle says. I think Aristotle would class diversity as a type of virtue because a diverse organization is better with regard to social justice than a non-diverse one, and (as the social scientists have shown), diverse scientific organizations do science and engineering better than non-diverse ones. Making something intrinsically good and also better at what it does are the two main aspects of a virtue (again, according to Aristotle), and diversity qualifies on both counts.
The next question is this: can you have too much diversity? Most virtues represent a mean or rough average between the two extremes of excess and deficiency. Assembling a competent technical organization with a mind to diversity represents a compromise between extremes. In the decades before diversity in its modern sense was recognized as an organizational goal, those in charge (usually white males) picked the best people they could while following the cultural norms of their time. These norms generally (but not always) excluded women and minorities, and tended to perpetuate the demographic makeup of the organization, while making it extremely hard or impossible for non-whites and non-males to enter. This was bad.
However, you can imagine an opposite extreme. The perfectly diverse organization would have diversity statistics identical to those of the largest applicable sample group: the state, the nation, or even the world. William F. Buckley is supposed to have said he'd rather be governed by the first hundred names in the Boston phone book than by the entire faculty of Harvard University, and in this proposal, at least, he was favoring the opposite extreme of diversity I am talking about. But if diversity is the only criterion of selection, the specialized competencies that a research or engineering organization needs will be absent, except by chance, and it will fail to achieve its objective, unless its only objective is to show that it is acceptably diverse.
The U. S. National Science Foundation has in recent years spent a substantial portion of its resources encouraging diversity in various ways. To the extent that these efforts have righted previous injustices committed either consciously or through unconscious bias against certain groups, they are to be applauded. But there is nothing scientific about the choices of which measures of diversity to work on.
In a secular democracy, these choices are made politically. And making politics your ultimate authority can land you in unpleasant places, as scientists in Russia and Germany have found. A crackpot biologist named Lysenko got his hands on the political levers of control in the old USSR in the 1920s. Lysenko thought acquired characteristics could be inherited, and for the next forty years, any Soviet biologist who disagreed with Lysenko about evolution was liable to disappear into the Siberian work camps. And the Nazi party in Germany took delight in calling Einstein's theory of relativity "Jewish physics." Such blatant overruling of science by politics can always happen if those in charge value political goals more than the integrity of science.
I am personally about as un-diverse as you can get: an old white male conservative Christian Texan. An organization composed of people like me would score close to zero on any diversity index you care to name. I view the diversity project as an attempt, however flawed, to show the type of love that wills the good of the beloved to people who would otherwise be kept from flourishing to the best of their abilities. There is nothing wrong with this type of love. It is the type of love Jesus Christ exhorted his followers to show to each other. But implementing diversity in a way that helps those who need that type of help without inflicting harm or the loss of opportunity on others is an inherently complex task. The only way to do it perfectly would be to have perfect insight into the problem of social justice, and only God has that. Any human attempt at diversity represents a compromise between using resources to increase diversity, versus using resources to address the task at hand. And those promoting diversity should remember that it is possible to have too much of a good thing.