One of the real tragedies of contemporary politics is that our most bitter disagreements are about something that doesn’t even exist—the political spectrum. Left and right are entirely tribal designations and have no unifying philosophy or principle behind them that can be represented on a unidimensional spectrum.

This may sound like an absurd claim, but before rejecting out of hand, consider that the political spectrum rests on an essentialist theory of ideology that has been soundly falsified. The essentialist theory says that, although it may seem that there are many distinct political issues in politics, there is actually just one big issue—an underlying essence that ties them all together (e.g., change vs. preservation, equality vs. freedom, order vs. liberty, realism vs. idealism, etc.). If politics is unidimensional (about one essential issue), then a unidimensional political spectrum is adequate to represent politics.

An alternative to this essentialist theory is the “social theory” of ideology, which says that distinct political positions correlate because they are bound by a unifying tribe. If the right-wing team is currently in favor of tax cuts and opposed to abortion, then those who identify with that team will adopt those positions as a matter of social conformity, not because both are expressions of some underlying principle. If the social theory is correct, the political spectrum is of little use because there is no single essence; instead there are many unrelated political issues and therefore many political dimensions.

To figure out which theory is correct, let’s test the predictions that each makes. The essentialist theory predicts that, since core principles define the political spectrum, we should find people holding a consistent set of “left” or “right” positions independent of socialization. In fact, we find the opposite. Jason Weeden and Rob Kurzban have shown that people don’t hold political views that fit ideological molds until after they are socialized into the left-right way of thinking. The less tribal and the more ignorant of the political spectrum someone is, the less their views will align neatly with current ideological configurations.

The social theory, which views the positions associated with right and left as tribal, not natural, predicts that changes among the tribe would lead to changes among ideologues. This is exactly what we find. Ideologues will hold opposite policy positions, depending on who supports the policy, and they are far more likely to change their positions to fit the politicians for whom they vote than they are to change their vote to a politician who fits their positions. Ideological self-categorization “taps not what the respondent thinks about various issues but rather the ideological label he or she finds most suitable.” As the social theory predicts, people first choose whom to identify with and then choose what to identify with in terms of policy. In the words of psychologist Dan Kahan, they “endorse whichever position reinforces their connection to others with whom they share important ties.” Social influence, not an underlying “essence,” explains the correlation we find between right and left-wing views on fiscal, social, and foreign policies. The game is “follow the tribe” as the social theory says, not “follow the principle” as the essentialist theory says.

Public opinion polls further reinforce the point, showing that left-right ideologues often switch their beliefs to conform to the tribe. In the past decade alone we’ve seen self-described conservatives go from being anti-Russia to more pro-Russia, strongly pro-trade to strongly anti-trade, believing that personal character matters a great deal in politicians to believing that it matters hardly at all, staunchly interventionist in foreign policy to staunchly isolationist. Where is the “essence” behind all of this variation? It doesn’t exist. The views associated with left and right are constantly shifting for social reasons that have nothing to do with essential principles.

The essentialist theory says that people come to join political tribes by starting with an essential principle, using that principle to arrive at hundreds of distinct political positions, and then joining the tribe that agrees with them on those positions. The social theory, on the other hand, says that this is backward: people first anchor into an ideological tribe, adopt the positions of the tribe as a matter of socialization, and only then invent a story to explain how an essential principle binds all of those positions together. Ideology is reverse-engineered to fit tribal actions and attachments. If the social theory is correct, then ideologies are, to use Jonathan Haidt’s words, “post hoc constructions designed to justify what we’ve just done, or to support the groups we belong to.”

An extensive analysis of election and public opinion surveys confirmed that people first anchor into an ideological tribe—because of family, peers, or a single issue they feel strongly about—and only then adopt the full-range of beliefs associated with that tribe. Ideological identification is primarily a cause, not an effect of a person’s political views. According to political theorist Michael Oakeshott, “Far from a political ideology being the quasi-divine parent of political activity, it turns out to be its earthly stepchild…political activity comes first, and a political ideology follows after.” Principle follows tribe.

The two theories also differ in how they view political parties. In the essentialist theory, ideologies are unchanging, transcendent principles, while parties are evolving social organizations that can be “captured” by the ideologies. In the social theory, by contrast, ideologies don’t capture parties; parties capture ideologies—that is, they redefine them. Once again, research supports the latter: what is considered “right-wing” or “left-wing” is simply whatever the Republican and Democratic Parties happen to stand for at a given moment. Left-right ideologies are tools of self-delusion—they let us indulge the fantasy that our partisanship is principled rather than tribal, i.e., that there is some noble ideal connecting all the distinct and unrelated issues that our party happens to support. But essentialist predictions do not hold up to reality.

The common retort of many essentialists is that conservatives or liberals who switch their positions so easily aren’t “true conservatives” or “true liberals.” But in this, the essentialists are falling prey to the “private language fallacy”—the erroneous belief that a private individual can arbitrarily determine the meaning of public words. The thousands of Fox News-watching, Bush-voting, Limbaugh-listening, CPAC-supporting people in these studies call themselves “conservatives,” the media calls them “conservatives,” and the politicians they support are coded as “conservative” in ideological voting measures; they are, therefore, “real conservatives” in the only sense that it’s possible to be a “real conservative.” Because there is no transcendent definition of ideology beyond the tribe, those who compose the liberal and conservative tribes are, by definition, “true” liberals and conservatives. Those who insist otherwise might be falling prey to motivated reasoning--seeking to justify their own ideology by appealing to principle.

I understand why so many of us want to believe in the political spectrum—it makes politics simple and gives us the illusion that our party’s beliefs have an underlying (and righteous) philosophical coherence—but it’s time to face up to the facts. “Right-wing” and “left-wing” are little more than tribal designations. Shedding our jerseys might help us become more rational, more humble, less tribal, and ultimately, more open-minded when it comes to public issues.