During the last century’s darkest political and social period—World War II and its prelude—Karl Popper completed The Open Society and Its Enemies, an articulate and impassioned defense of the social and political philosophy of democratic liberalism. The rule of law, free inquiry, toleration, universal suffrage and reason, are values of democratic liberalism—Popper’s open society. Parallels between his era and our own are disturbingly obvious, with demagoguery, political violence, hate and a narrow tribalism of values threatening democratic institutions. Although his approach was not entirely original, Popper expressed his values and intellect in a persuasive and powerful philosophical style. His expertise was in the philosophy of science and critical history, and both disciplines gave him insights especially relevant today, concepts expressing the values and presuppositions of a society capable of adaptation, justice and all forms of human flourishing.

Popper’s starting point was epistemological—his theory of the nature of knowledge—a scholastic sounding word, but just the right fit for what we’ll be considering. He viewed our knowledge of the world as always provisional, incomplete and never absolute. Its quest is on-going, thus lacking certainty. But by no means did he question the worth of science, ordinary problem-solving or other forms of inquiry. Popper was confident that humans, sharing attitudes of “reasonableness” and integrity, will reach something “approaching the truth” (Popper’s phrasing in quotes). Gaining knowledge requires a common thread of humility, a readiness to listen to critical arguments from others, and a willingness to learn from experience—defining a critical and open mind. A central theme is the social character of “reasonableness”. Reasoning, like language, is a product of social life, and given suitable circumstances, becomes a powerful unifier of humankind. Significantly, Popper’s theory of knowledge carries as much relevance to questions of social and economic policy, as it does to formal science.

Popper’s mid-20th Century’s epistemology shares a great deal with a current, widely accepted theory of knowledge: abduction—inference to the best explanation, a form of reasoning centered on likelihoods. In abduction, one seeks the most likely explanation of all the relevant facts, or phenomena, in question. In a sense, inference is directed backwards, where one infers the hypothesis giving the most plausible explanation of known facts. The process is iterative, a bit messy, and quite ordinary. In fact, it’s a process all of us use when tasked with typical problem-solving challenges, whether in daily life or work-related environments. And inquiry in science is merely a more formal, specialized, or sometimes more esoteric enterprise. Being open-ended, abduction’s initial conclusions are amenable to change based upon new information or new argument, bringing consecutive refinements.

Both Popper’s attitude of “reasonableness”, and abductive reasoning, are antithetical to authoritarian theories of knowledge—and to authoritarian societies. We can view the nature of a given society and its specific theory of knowledge as conjoined. Authoritarian societies claim to be the source of total and absolute truth, and strongly promote, or coerce, adherence not only to their core beliefs, but also the acceptance of their own infallibility. Both secular and theocratic authoritarian societies have followed this pattern. Sometimes the sources of unquestioned truth are “sacred” documents (secular or religious) or the words of an “oracle”, often a charismatic, authoritarian leader. In both cases knowledge is not gained through a give-and-take process, where citizens, or legislators, freely and with (more-or-less) open minds, form a tentative, majority consensus of the salient facts, and forge ahead with public policy decisions—a shared vision that “approaches the truth”, as Popper might say. Authoritarian societies morph truth into blatant political expression—political in a pejorative sense—where the pull of ideology, ego or self- righteousness overwhelm standards of evidence and critical thinking. Decision-making in open societies respects perspectives from varied sources, since no single point of view can be an “objective” mirror of the facts and issues. Any majority consensus, while imperfect and leaving a minority dissatisfied, can be reshaped in the future, as circumstances and political dialogue evolve. The rule of even-handed law, the rejection of violence and an ethic of civility, define public life in an open society.

When a large society is pluralistic, like 21st Century America with numerous sub-cultures (some very active politically), establishing and sustaining an open society—one successfully blending justice, free expression and inquiry, tolerance, and broadly-based flourishing—requires citizens embracing both commonality (universality) and difference. To think this process is free of serious challenges would be simplistic as well as foolish, given the contrasts within our multicultural society, especially our political differences. But equally vexing conflicts have been faced earlier in the nation’s history, with varying success, and this could become one of the more positive periods.

America’s 330 million citizens can be classified in numerous ways, but the most useful for this essay are racial mix, ethnicity, religiosity, political orientation, and philosophical/ethical presuppositions. Clearly these categories overlap and are often paired. Considering the first category, America’s varied ethnic backgrounds should not compromise an ethic of commonality—a sense of shared humanity—and their variety and richness may be enhancing it, especially in urban areas. But there is danger in taking too seriously philosophies of ethnic “identity”, where an overdose of essentialism makes it difficult to appreciate the universals all of us should be sharing, especially common epistemologies and standards of truth—most crucially the basic tenants of an open society. Exaggerated essentialist or “identity” thinking forms a protective, isolating bubble, limiting intellectual, social and ethical growth. Each of us is capable of becoming more than the parameters defined by our family, ethnic memes, gender, or whatever other descriptions are originally given to us. Humans are adaptive, learning beings.

A pluralistic, open society must value justice, yet America’s history of racial bias has been grievous. While negative aspects of slavery’s legacy have not been eliminated, motivation has grown dramatically to bring authentic levels of respect and equity among all racial groups. Residual institutional bias is being strongly challenged, giving real legitimacy for optimism. Vocal elements of white supremacy have not disappeared, but their image is tarnished and could become peripheral, maintained in small numbers only, existing by means of irrational emotion and habit.

The remaining four differentiating categories—those reflecting overall worldviews and values (often fervently held)—maintain a powerful hold on the human psyche. Here I’m thinking of the philosophical spread between, say, libertarian-Randian-free market capitalists and democratic socialists, or between fundamentalist Christians and secularists. These capture sharply contrasting perceptions of what we should value, believe, even how we should think. Individual (and sub-group) values are fundamentally at stake, making these issues charged both emotionally and philosophically. How might commonality be reached when worlds are so different?

First, we need to accept that some individuals and cultural sub-groups, those holding the most extreme and rigid views, will never accept the principles of a pluralistic, open society, remaining a long-term presence on the periphery of any liberal, democratic society. Their influence will wax and wane, depending upon the vigor of the greater society. Contemporary examples include the Christian Nationalist movement, and the more extreme anti-government militia movements. The former promotes a theocratic America, while the latter groups have challenged the rule of law, and physically intimidated elected officials and democratic processes. The existence of ideologically extreme and hardened cultural groups makes it all the more necessary for those believing in a tolerant, pluralistic, civil society, to coalesce into an active majority advocating these values. And this must include secularists, as well as those of faith, most liberals and conservatives, people of all classes, ethnicity and racial mix. Doing so requires a shared confidence and belief in “matters of fact”—common reference points for “truth”. This brings us back to Karl Popper, whose ideas are as relevant now as during his era—the social character of “reasonableness”, maintaining an open mind, and willingness to listen and learn. And essential for strengthening feelings of shared humanity is a commitment to avoid dismissiveness toward others whose world views are at odds with our own (Popper would no doubt protest a "cancelling” culture). As a secular humanist, I have never fully understood how someone gains faith and religious commitment, but I can respect their choice to be as they are. Yet we share many ethical sensibilities and most of our perceptions of the world, even if important philosophical views are fundamentally polar. Those differences affect the minority of our on-going life decisions. We often hold similar views on public policy questions, and the few exceptions do not negate a strong appreciation of common citizenship. Our reference points for “facts” and “truth” are similar, especially concerning the reality of social and economic issues, although our individual solutions to problems may differ. But even given these differences, it is possible to frankly articulate views, and learn in the process. Of course, an environment of shared “facts” cannot exist without widely accepted sources of reliable information, and we know this is often not the case today. That significant segments of society no longer hold confidence in similar sources is distressing, and has become a crisis for a healthy society, politically and socially—the result of a fractured epistemology.

A pluralistic, open society does not require, or even desire, a totally shared cultural reality—that would amount to an internal contradiction—but the greater part of society must sustain the values and norms of its constitutional and legal structures. Commitment to the rule of law, free expression and inquiry, toleration, reason and justice, must be in the minds of a large majority of society. But for this to become a fact for 21st Century America, the credibility and accuracy of public sources of information—a common, rudimentary reality—must return to a functional level. Politicizing “facts” and “truth” brings chaos and perpetual social dysfunction. Strengthening honest, professional journalism, with a clear distinction between factual news reporting and commentary, carries immense social value. And the efficacy of science must be imbedded in all public policy discussions. Popper would view contemporary assaults on science as not only disturbing, but surprising, given our era’s success and sophistication with basic research and technical achievement.

Popper’s vision of an open society closely parallels traditional democratic liberalism, and his deep commitments to free inquiry, empiricism and science add substance. While the issues of justice and egalitarianism were peripheral in his work, they are not inconsistent with his fundamental ideas. And as we enter the third decade of the new millennium, these principles have become urgent for America, and underlie a pluralistic, open society. A more just and egalitarian structure will enable a flourishing mega-community of 330 million citizens.

What happens to those who oppose this vision? Their numbers are not small, and will zealously advocate opposing visions for society. Those who think otherwise must nurture the broadest possible support for an open society, and this means enhancing inclusivity by every means imaginable—impossible without promoting egalitarian economic and social standards. Even after this project succeeds, those promoting authoritarian and restrictive philosophies will still exist—in some form—as a permanent threat to liberal democracies.