This book serves as a defense of the ideals that emerged most clearly during the Enlightenment period: reason, science, humanism, and progress. The author argues that these ideals, which took shape over two centuries ago, are not only relevant today but more necessary than ever. While the gifts of the Enlightenment—like longer lifespans, readily available food and water, effective medicine, safety, freedom, and access to knowledge—are often taken for granted in fortunate parts of the world, they are, in fact, human accomplishments rather than guaranteed birthrights. Countries can regress, and the achievements of the Enlightenment should not be ignored. The central purpose of the book is to restate these ideals for the 21st century and demonstrate, using data, that the Enlightenment project was not a naive hope but something that has worked. This triumph is often "unsung," leading to the ideals themselves being unappreciated. Contrary to being a simple consensus, these ideals are frequently met with indifference, skepticism, and even contempt today. #### The Core Ideals of the Enlightenment The Enlightenment, conventionally placed in the last two-thirds of the 18th century but with roots stretching back further, was an era where thinkers, prompted by new scientific discoveries, exploration, and the aftermath of religious wars, sought a new understanding of the human condition. Four main themes emerged: 1. **Reason:** This is presented as nonnegotiable. Simply by engaging in discussion and seeking justification for beliefs, one commits to reason and holding those beliefs accountable to objective standards. Enlightenment thinkers insisted on applying reason to understand the world, rejecting reliance on faith, dogma, authority, or mystical experiences. The application of reason led many to question traditional religious beliefs, seeing them as products of human imagination rather than divine revelation. While acknowledging human irrationality and passions, thinkers like Kant and Hume emphasized the need for the deliberate application of reason precisely because our natural thought habits are not always reasonable. The capacity for reason is deeply rooted in human nature and evolution. Exploring the nature and limits of human reasoning is a rich area of study in cognitive psychology and philosophy, and the book suggests collective rationality can be cultivated through institutions and norms like free speech and empirical testing. 2. **Science:** Science is seen as the refinement of reason for understanding the world. The Scientific Revolution was profoundly transformative, moving understanding away from superstitions about witches, werewolves, spontaneous generation, and astrological portents. For Enlightenment thinkers, escaping such ignorance showed how conventional wisdom could be wrong and that scientific methods—like skepticism, questioning certainty (fallibilism), open debate, and testing ideas against evidence—are the way to reliable knowledge. This desire for understanding extended to humans themselves, prompting a "science of man" that touched on what we now call cognitive psychology, evolutionary psychology, social psychology, and cultural anthropology, exploring universal human nature alongside cultural diversity. Science allows for an increasing confidence in hypotheses as evidence builds, rather than claiming infallibility upfront. It is seen as indispensable in all areas of human concern, offering explanatory depth and revealing deep principles about the universe, life, and mind. The connection between science and the humanities is explored as a potential source of new insights and a richer understanding of the human condition and creative endeavors. 3. **Humanism:** Haunted by the history of religious violence, the Enlightenment thinkers sought a secular basis for morality. Humanism provides this foundation by prioritizing the well-being of individual people over the interests or glory of groups like tribes, nations, or religions. Individuals are the ones who experience pleasure and pain, fulfillment and anguish. Whether framed as maximizing happiness for the greatest number or treating individuals as ends in themselves, humanism centers moral concern on the universal capacity for suffering and flourishing. The book suggests that human nature, particularly our capacity for sympathy, helps us respond to this moral call, potentially expanding our circle of concern to all humankind, leading to cosmopolitanism. This sensibility drove the condemnation of practices like slavery and cruel punishments, leading some to call the era the Humanitarian Revolution. Humanism is a moral commitment that grounds values in human welfare, needs, and interests as tested by experience, extending concern to the global ecosystem. It's depicted as a moral code that rational and diverse people needing to coexist might converge upon, clashing with alternatives like blind obedience to divine dictates or romantic heroism. The Universal Declaration of Human Rights is presented as a key humanist manifesto. The connection between humanism and scientific ideas like entropy and evolution is explored, suggesting these provide a deeper foundation for understanding human needs and the challenges of existence. 4. **Progress:** With understanding advanced by science and sympathy expanded by reason and cosmopolitanism, the Enlightenment thinkers believed humanity could achieve intellectual and moral progress. This wasn't a belief in an automatic, mystical upward march, but a more practical idea: by observing how things are, thinking of improvements, trying them out, and keeping what works, the world can be gradually made better. Science itself operates this way. Progress is also seen in the creation of wealth through knowledge and cooperation, not just its distribution. Human institutions like governments, laws, and markets were viewed as human inventions designed for human betterment. Peace, historically seen as fleeting, became a practical problem to be mitigated and solved through measures like international commerce, representative governments, and international cooperation. The book argues that progress is not a naive hope, but something that has worked, with indicators of human welfare showing cumulative gains over time. Examining the data behind global trends in health, wealth, safety, freedom, and knowledge provides a detailed picture of this progress, a topic explored extensively in the book. #### Challenges and Counter-Enlightenment Ideas Despite the appeal of these ideals, they are constantly challenged. The Enlightenment was quickly followed by counter-movements, and the West remains divided. - **General Opposition:** Since the 1960s, trust in modern institutions linked to the Enlightenment has declined. Political movements explicitly rejecting these ideals have risen, often emphasizing tribalism, authority, disdain for experts, and nostalgia. This opposition isn't just grassroots but has a long history in intellectual and artistic culture. - **Romanticism:** This movement emphasized emotion over reason, collective identity over the individual, and saw heroic struggle and even violence as inherent to life, opposing the Enlightenment's focus on problem-solving and peace. - **Religious Faith:** Defined as belief without good reason, faith inherently clashes with reason. It can also conflict with humanism by elevating non-human concerns above human well-being or devaluing earthly life. Science and religious faith have a history of conflict over explanations of the natural world. Theistic morality, based on obeying divine dictates, is presented as an alternative to humanism's focus on human flourishing. - **Collectivism and Nationalism:** These ideas see individuals as subservient to a larger group entity, prioritizing its glory over individual well-being. Nationalism in this sense contrasts with civic values focused on cooperation for members' flourishing. Authoritarian populism is characterized as a modern form of tribalism that rejects individual rights and expert knowledge. - **Cultural Pessimism and the "Second Culture":** Many intellectuals, particularly in the humanities, are portrayed as having a disdain for modernity, seeing technological capitalism as soul-deadening. They may welcome societal collapse, believing a better order can only emerge from the rubble. There's often a disdain for science, seen as merely fixing mundane problems or blamed for historical atrocities. Some intellectuals, forming what's termed a "Second Culture," prioritize erudition and subjective judgment over scientific methods and fear the "intrusion" of science into the humanities, viewing it as threatening freedom and dignity. This leads to "progressophobia," a resistance to the very idea that the world is or can get better. #### Defending the Ideals The book mounts a defense against these challenges, particularly addressing criticisms from intellectual circles. - **Defense of Reason:** The act of engaging in argument implicitly commits one to reason. While cognitive psychology shows humans are prone to biases, this doesn't mean humans are _incapable_ of rationality or that seeking a more rational world is futile. Enlightenment thinkers knew humans weren't perfectly rational but argued they _should_ strive for rationality and that collective reason can be cultivated through appropriate institutions and norms. The world, in fact, is becoming more rational in many practical domains like medicine, policy, and business, despite the irrationality often seen in areas like electoral politics. The process of identifying and correcting biases is part of reason's self-healing power. - **Defense of Science:** Science is not just about empirical facts but involves mathematics, logic, theories, and values. It operates on the ideals that the world is intelligible—explicable by deeper principles—and that our ideas about the world must be tested against reality, using methods like conjecture and refutation or Bayesian reasoning. Blaming science for historical evils often reverses the historical timeline; evils like genocide were prevalent _before_ the spread of science and liberal Enlightenment values. Science offers astonishing knowledge and has brought immense benefits, such as eradicating diseases like smallpox. Spreading scientific thinking can greatly enhance human welfare in various domains. Furthermore, science offers opportunities for deep insight into traditionally humanistic areas, suggesting a potential "consilience," or unity of knowledge, rather than a threat. - **Defense of Humanism:** Humanism's goal is human flourishing, providing a non-supernatural basis for meaning and ethics ("good without God"). It grounds values in human needs and interests, which can be illuminated by scientific understanding of what it means for complex biological systems to exist and thrive in the physical world (drawing on ideas like entropy and evolution). The consequentialist aspect of humanism, evaluating actions by their effects on well-being, is argued to have a strong track record in driving moral progress, leading to the abolition of cruel practices and the advancement of human rights. While humanism may seem less emotionally stirring than faith or romantic heroism, it is a moral code that has fostered peace and prosperity in societies that embrace it. #### Conclusion: The Case for Continuing Progress The book concludes that the Enlightenment ideals of reason, science, and humanism have been successful in improving the human condition over the past two and a half centuries. Despite ongoing problems and challenges from counter-Enlightenment movements, the data shows significant, cumulative progress in many aspects of human welfare. Problems are inevitable, but the core message is that they are solvable. The author calls for recognizing this progress and actively defending the ideals that made it possible. This involves using data to understand the world accurately, applying critical thinking to evaluate claims, and resisting narratives that promote cynicism, tribalism, and authoritarianism. The story of human progress, driven by reason, science, and humanism, is presented not as a dry academic topic but as a heroic, uplifting, and even spiritual narrative about humanity overcoming immense odds. The case for "Enlightenment Now" is a call to appreciate the gains made, understand the ideas behind them, and apply those same ideas to tackle the problems that remain, trusting in the capacity of knowledge, reason, and human sympathy to continue making the world a better place. This ongoing effort requires continuous engagement and defense against ideas that pull us back toward ignorance, dogma, and conflict.