The Rise of Secularism
The rise of secularism is one of the most important developments in the history of religious ideas because it changed not only how people thought about religion, but also how they understood knowledge, government, morality, human freedom, and the meaning of life. Secularism did not appear suddenly, and it was not simply a rejection of religion. It emerged gradually from within societies that had been deeply shaped by religion. Over many centuries, religious authority became increasingly differentiated from political authority, scientific inquiry became increasingly independent of theological explanation, and moral reasoning increasingly came to rely upon human experience, reason, and universal principles rather than religious revelation alone.
To understand secularism historically, it is important to distinguish it from atheism. Atheism is the denial, or absence, of belief in God or gods. Secularism is primarily concerned with the organization of public life and the sources of authority within society. A secular society does not necessarily deny religion. Rather, it seeks to prevent one religious tradition from possessing exclusive control over government, law, education, or public institutions. A person can therefore be deeply religious and also support secular government. Likewise, a secular society can contain large numbers of religious believers.
The origins of secularism reach back much farther than the Enlightenment. Ancient societies generally did not separate religion from public life in the modern sense. In Egypt, Mesopotamia, Greece, Rome, Israel, India, China, and elsewhere, religion was intertwined with political authority, social customs, and explanations of the natural world. The gods, ancestors, kings, priests, rituals, laws, and institutions belonged to a single cultural system. There were certainly ancient thinkers who questioned traditional religion. Greek philosophers such as Xenophanes, Epicurus, and Lucretius offered powerful criticisms of popular ideas about the gods. Yet ancient societies did not develop the modern concept of a religiously neutral state.
The emergence of Christianity initially created a new relationship between religious and political authority. Christianity proclaimed a kingdom of God that transcended earthly political structures. Jesus’s teaching about giving Caesar what belongs to Caesar and God what belongs to God eventually became enormously influential, even though Christians continued to debate what the distinction actually meant. As Christianity became connected to the Roman Empire, however, the relationship between church and state became increasingly complicated. After the collapse of the Western Roman Empire, the Christian church became one of the major institutions capable of preserving intellectual, educational, and administrative continuity in Europe.
During the medieval period, Western Christianity became deeply embedded in political and social life. The church was not simply a place of worship. It operated schools, universities, charitable institutions, courts, and systems of law. Bishops could possess substantial political authority, and kings and emperors often sought religious legitimacy for their rule. At the same time, medieval Christianity contained within itself ideas that would eventually contribute to the development of secular thought. Medieval theologians distinguished between different kinds of authority, developed sophisticated theories of natural law, and argued that human reason could discover important truths about the world.
The medieval university was particularly important. Christian thinkers such as Thomas Aquinas believed that reason and revelation ultimately came from the same divine source and therefore could not genuinely contradict one another. This encouraged systematic investigation of philosophy, nature, ethics, and politics. The medieval intellectual world was profoundly religious, but it also developed methods of rational inquiry that later generations would use in increasingly independent ways.
Another important development was the revival of classical learning during the Renaissance. Beginning particularly in Italy and spreading throughout Europe, Renaissance humanism placed renewed emphasis upon human experience, classical literature, historical scholarship, rhetoric, and the capacities of human beings. Renaissance humanists were not necessarily secular in the modern sense. Many were deeply Christian. What changed was the increasing confidence that human beings could investigate their world through reason, historical study, observation, and artistic creativity.
The Protestant Reformation of the sixteenth century accelerated the transformation of religious authority. Martin Luther, John Calvin, and other reformers challenged the authority and practices of the Roman Catholic Church. They insisted upon the importance of scripture and challenged the centralized ecclesiastical authority of the papacy. The result was not secularism. In many places it produced societies that were intensely religious. Yet the Reformation fractured the religious unity of Western Europe and made it increasingly difficult for political society to assume that everyone would accept a single religious authority.
The religious wars of the sixteenth and seventeenth centuries made this problem especially urgent. Catholics and Protestants fought over theology, political authority, territory, and the identity of states. The Thirty Years’ War, which devastated much of Central Europe between 1618 and 1648, became a powerful symbol of the destructive possibilities of religious conflict. Gradually, political thinkers began searching for arrangements that could allow people of different religious convictions to live together without perpetual warfare.
This development contributed to the emergence of religious toleration. Thinkers such as John Locke argued that government should not attempt to control people’s religious beliefs because genuine faith could not be produced by political coercion. Religious toleration did not initially mean universal equality. Locke himself placed limits on whom he believed could safely be tolerated. Nevertheless, the principle that government should distinguish between civil interests and religious belief became enormously important.
The Scientific Revolution transformed the intellectual environment even more profoundly. Beginning in the sixteenth and seventeenth centuries, figures such as Nicolaus Copernicus, Johannes Kepler, Galileo Galilei, and Isaac Newton developed increasingly powerful mathematical and observational approaches to understanding nature. Their discoveries did not simply destroy religious belief. Many of the great scientists of the period were themselves religious believers. Newton, for example, was deeply interested in theology.
The deeper transformation was methodological. Nature increasingly came to be investigated through observation, mathematics, experimentation, and reproducible evidence. Questions about the physical universe could increasingly be answered without beginning with theological assumptions. This did not prove that God did not exist. Rather, it created a growing sphere of knowledge in which appeals to religious authority were no longer necessary to explain particular natural phenomena.
The Enlightenment of the eighteenth century carried these developments further. Enlightenment thinkers placed extraordinary confidence in reason, evidence, individual freedom, and the capacity of human beings to improve society. Some remained religious. Others became deists, believing in a creator who established the universe but did not intervene continually in human affairs. Still others became openly skeptical of organized religion.
The Enlightenment also transformed the understanding of political legitimacy. Traditionally, kings often claimed that their authority came from God. Enlightenment political thinkers increasingly argued that legitimate government derived from the consent, rights, or interests of human beings themselves. John Locke emphasized natural rights and government by consent. Jean-Jacques Rousseau explored popular sovereignty. Immanuel Kant emphasized human autonomy and the responsibility of individuals to think for themselves.
This represented a major change in the history of religious ideas. Authority was increasingly moving from an external sacred hierarchy toward the autonomous human individual. The question was no longer simply, “What has God revealed?” It increasingly became, “What can human beings know through reason?” and “What principles should rational people accept?”
The American and French Revolutions demonstrated two different possibilities within this transformation. The American founding established a political system that prohibited the creation of a national established church while protecting the free exercise of religion. Religion remained enormously important within American society. The American experiment therefore illustrated one form of secularism in which government was separated from religious establishment without requiring society itself to become nonreligious.
The French Revolution took a more radical direction. The revolutionaries challenged the political power of the Catholic Church and attempted to reorganize society around ideals of citizenship, reason, and republicanism. During the most radical period, revolutionary leaders even attempted to replace traditional Christian religious practices with new civic forms of worship. These experiments demonstrated both the attraction and the dangers of trying to construct a completely rational public culture by suppressing traditional religion.
The nineteenth century witnessed another major stage in the rise of secularism. Industrialization, urbanization, literacy, scientific progress, and political democratization transformed European and North American societies. Religious belief remained powerful, but traditional institutions increasingly competed with new intellectual and social authorities.
The publication of Charles Darwin’s theory of evolution by natural selection in the nineteenth century became especially significant. Evolution did not logically disprove God, and many Christians eventually reconciled evolutionary theory with religious belief. Nevertheless, Darwin’s theory challenged traditional explanations of biological diversity and human origins. It demonstrated that a major area of human understanding could be explained through natural processes without requiring a direct appeal to supernatural intervention.
Historical scholarship also began treating the Bible as a collection of texts that had emerged within particular historical cultures. Scholars examined authorship, composition, language, sources, textual transmission, and historical context. The Bible remained sacred to believers, but scholars increasingly approached it as an object of historical investigation as well.
This produced an important distinction between theological and historical approaches. Theology asks questions such as what a sacred text means for faith. Historical criticism asks when a text was written, by whom, for whom, and under what circumstances. The two approaches can coexist, but they operate according to different rules of evidence.
At the same time, modern philosophy became increasingly willing to challenge religious assumptions. Ludwig Feuerbach argued that human beings project their own ideals onto God. Karl Marx interpreted religion partly in relation to economic and social structures. Friedrich Nietzsche famously declared that “God is dead,” meaning not simply that an individual deity had ceased to exist, but that traditional Christian assumptions were losing their authority within modern European culture.
Nietzsche understood the consequences of secularization more deeply than many of his contemporaries. If traditional religious belief provided the foundations for morality and meaning, what would happen if those foundations disappeared? Secularism could liberate human beings from inherited authorities, but it also created a new problem. If morality no longer rested upon divine command, where would moral obligation come from? If the universe had no guaranteed purpose, how could human beings find meaning?
This became one of the central questions of modernity.
The nineteenth and twentieth centuries therefore witnessed both the expansion of secular institutions and the persistence of religion. Sociology, psychology, anthropology, economics, political science, and the natural sciences developed as independent disciplines. Universities increasingly became institutions in which knowledge could be pursued without theological oversight. Modern states developed legal systems that increasingly applied to citizens regardless of their religious affiliation.
Secularization also spread beyond Europe. European imperialism carried modern political institutions, education systems, science, and secular intellectual ideas around the world. In some societies, secularism became associated with modernization and national independence. In others, it was experienced as part of Western cultural domination. This distinction is important because secularism was never simply a neutral intellectual development. It was also embedded in political power, colonialism, and competing visions of modernity.
In the twentieth century, secularism took several different forms. Liberal democracies generally moved toward religious neutrality, although the relationship between religion and government differed considerably from country to country. Some states maintained established churches while becoming increasingly tolerant of religious diversity. Others adopted strict separation between religion and government. Still others attempted to suppress religion altogether.
Communist regimes represented the most aggressive form of state-sponsored secularism. The Soviet Union and several other communist governments regarded religion as a competing source of authority and attempted to diminish or eliminate its influence. Religious institutions were restricted, persecuted, or placed under state control. Yet the experience of communist societies demonstrated that suppressing religion does not necessarily eliminate religious longing. Religious identity sometimes survived underground and reemerged when political restrictions were relaxed.
The twentieth century also produced secular philosophies that did not necessarily deny God but sought to construct meaning without relying upon traditional religious authority. Existentialists such as Jean-Paul Sartre argued that human beings must confront a world in which meaning cannot simply be assumed. Albert Camus explored the apparent absurdity of existence and argued that human beings could nevertheless live with courage, integrity, and solidarity.
Other philosophers took different approaches. Secular humanism emphasized human dignity, reason, compassion, ethical responsibility, and the improvement of human life. Instead of asking how people should live because God commands it, secular humanists asked how people should live because human beings share vulnerability, interests, relationships, and responsibilities toward one another.
This represents one of the most important developments in the history of religious ideas. Morality increasingly became something that could be discussed independently of theology. Questions about justice, human rights, equality, democracy, and human dignity could be framed in universal human terms.
Yet secularism did not produce a simple replacement of religion by science. The actual historical situation has been far more complicated. Religious belief continued to flourish throughout the modern period. Evangelical Christianity grew dramatically in parts of the world. Islam remained a major intellectual, cultural, and political force. Hinduism and Buddhism underwent significant transformations and global expansion. New religious movements emerged. Jewish religious life developed in new ways. Spiritual movements outside traditional institutions also multiplied.
In fact, the twentieth and early twenty-first centuries have demonstrated that modernization does not necessarily produce universal atheism. Sociologists increasingly distinguish between secularization and the decline of religion. A society may become secular in its political institutions while remaining deeply religious among its citizens.
Europe provides one of the clearest examples. Many European societies became highly secular, with declining church attendance and declining confidence in traditional religious institutions. Yet religious ideas did not simply disappear. They continued to influence art, ethics, political debates, holidays, cultural identity, and ideas about human dignity.
The United States followed a different path. American government developed a strong principle of religious nonestablishment, but American society remained highly religious. This demonstrated that separation of church and state does not necessarily lead to secularization of society.
The contemporary world therefore contains multiple forms of secularism. One form emphasizes separation between religion and government. Another emphasizes the decline of religious belief. Another emphasizes the independence of scientific and academic institutions from religious authority. Still another refers to a cultural condition in which people encounter many competing worldviews and can no longer assume that one religious tradition provides the unquestioned framework for everyone.
The philosopher Charles Taylor has described this transformation as a movement toward a society in which belief in God is no longer the automatic background assumption. In earlier societies, disbelief could seem almost unimaginable. In modern societies, both belief and unbelief are possibilities among many. A person may believe, doubt, reject religion, combine elements of several traditions, or remain uncertain.
This is perhaps the deepest meaning of secularization. It is not simply that fewer people go to church or that science has replaced theology. It is that religious belief has become one possible way of interpreting existence among several competing possibilities.
The rise of secularism therefore transformed the question of ultimate reality. In a predominantly religious society, the existence of God is often the starting point from which other questions follow. In a secular society, the existence of God itself becomes a question. Religion moves from being the unquestioned framework of public life to being one worldview among others.
This transformation also changed the meaning of personal freedom. Earlier societies often assumed that religious identity was inherited. People were born into a religious community and normally remained within it. Modern societies increasingly allow individuals to choose their religious commitments. This freedom can produce genuine spiritual exploration, but it can also produce uncertainty and fragmentation.
The individual therefore gained freedom while losing some of the certainty provided by inherited traditions. This is one of the central paradoxes of modern secular life.
Secularism also transformed the concept of authority. In a traditional religious culture, authority might be located in scripture, clergy, tradition, sacred institutions, or divine revelation. Modernity redistributed authority among scientific institutions, universities, democratic governments, courts, professional organizations, media, and individuals themselves. None of these authorities became universally accepted, and modern people increasingly had to decide which authorities they trusted.
This created a new intellectual responsibility. If no single institution possesses unquestioned authority, individuals must evaluate competing claims. The modern person becomes, in an important sense, a chooser of worldviews.
Yet secularism has never completely escaped the questions traditionally addressed by religion. Science can explain many mechanisms of the universe, but it does not by itself answer why there is something rather than nothing. Psychology can investigate religious experience, but explaining the experience does not necessarily determine whether its object is real. Biology can describe human origins, but it does not by itself establish what human beings ought to value. Political philosophy can develop theories of justice, but it cannot eliminate the deeper question of why justice should matter.
This is why the rise of secularism should not be understood as the disappearance of religious questions. Instead, secularism changed the setting in which those questions are asked.
The modern world continues to ask the ancient questions. Is there a God? Is there ultimate reality? What is the nature of the self? Do human beings possess free will? What is the basis of morality? What happens after death? What makes life meaningful? How should we live? What does justice require? What is love? What is forgiveness?
Religious traditions continue to answer these questions through revelation, tradition, ritual, and spiritual experience. Secular philosophies answer them through reason, experience, ethics, science, existential reflection, and human solidarity. The result is not the end of the history of religious ideas but a new stage in that history.
The rise of secularism can therefore be understood as a long movement from a world in which religion provided the dominant framework for nearly every dimension of life toward a world in which religious belief exists alongside many other forms of knowledge and meaning. It involved the differentiation of church and state, the independence of science, the development of religious toleration, the rise of individual rights, the growth of historical criticism, the expansion of democratic government, and the emergence of philosophies that sought to establish meaning and morality without requiring religious belief.
But secularism has also created its own profound questions. Freedom from religious authority can become freedom from inherited meaning. Scientific explanation can leave unanswered questions about purpose. Individual autonomy can become isolation. Religious pluralism can produce tolerance, but it can also produce uncertainty about truth. The disappearance of shared religious assumptions can liberate society from coercion while simultaneously making it more difficult to establish common moral foundations.
In this sense, the rise of secularism is not simply a story about religion losing power. It is a story about authority being redistributed. It is a story about human beings increasingly claiming the right to investigate reality for themselves, to choose their beliefs, to construct political institutions without religious establishment, and to seek moral principles that can be shared across religious boundaries.
The most important historical development may therefore be the emergence of a new relationship between faith and doubt. In the ancient and medieval worlds, doubt often existed within a religious framework. In the modern world, doubt itself became a legitimate intellectual position. Belief became something that increasingly had to be chosen, defended, reconsidered, and personally appropriated.
The rise of secularism thus changed religion without necessarily destroying it. Christianity, Judaism, Islam, Hinduism, Buddhism, Taoism, and other traditions entered modernity having to respond to science, democracy, pluralism, historical criticism, individual freedom, and competing philosophies. Some responded defensively. Others reinterpreted their traditions. Still others discovered new forms of religious and spiritual life.
The history of secularism consequently leads to a surprising conclusion. Modernity did not simply replace religion with reason. Instead, it created a world in which reason, science, democracy, personal experience, tradition, and religious faith must coexist and continually negotiate their claims.
The religious question therefore remains alive. What has changed is the authority with which the answer can be imposed. In a secular age, belief must increasingly persuade rather than simply command. Faith becomes less a matter of unquestioned cultural inheritance and more a matter of personal conviction, interpretation, and exploration.
That is the great turning point represented by the rise of secularism in the history of religious ideas. Humanity moved from a world in which religion largely defined the framework within which reality was understood to a world in which religion itself became one participant in a much larger conversation about reality, knowledge, morality, freedom, and meaning. The conversation is not finished. Indeed, the secular age may be understood not as the end of religious history, but as the beginning of an unprecedented period in which religious and nonreligious interpretations of existence must encounter one another openly.