The myriad of cultural narratives across our world is permeated by figures characterized with spiritual significance, figures who have etched indelible imprints on the sands of historical time, socio-cultural dynamics and spiritual narratives. Among these stand prophets and religious figures, characterized by their receipt of divine messages or their profound spiritual discoveries.

Emerging from varying cultural backgrounds and epochs, prophets are religious leaders credited with divine revelation, bearing messages of spiritual, social and sometimes political import, to their contemporaries and to posterity. Meanwhile, religious figures, while akin to prophets, might not necessarily claim divine encounters. They are, nonetheless, important personalities who have established, promoted or revolutionized religious or spiritual systems. It is critical to recognize the vast diversity that exists in the definition and interpretation of these figures across cultures, religions, and epochs.

These prophets and religious figures wield significant influence within various cultures, extending their reach far beyond their immediate cultural context. Their teachings have not only formed the basis for various religious formations or transformations but have also played crucial roles in shaping societal norms, laws, ethical systems and philosophical discourses. Indeed, these figures and their teachings are often intertwined with the cultural and personal identity of people across the globe.

In this series, our lens will add a focused illumination to four such figures whose influence continues to be substantially felt across various regions and societies: Moses, Jesus, Muhammad, and Buddha. These individuals have been selected not as an exhaustive representation of prophets and religious figures across cultures and times, but rather for the broad-reaching impact and enduring legacy of their teachings, and for their role in establishing the religions of Judaism, Christianity, Islam, and Buddhism respectively.

Moses, often depicted as the Liberator and Lawgiver, played a cardinal role in the formation of the Jewish identity as well as significantly influencing both Christianity and Islam. Jesus of Nazareth, hailed as the Messiah and Christ by followers, established the foundations of Christianity and left an enduring theological legacy via his life, teachings, crucifixion, and resurrection. Muhammad, revered as the Last Prophet in Islam, was instrumental in the formation of Islamic society and culture, plus his life and teachings dramatically shaped Islamic traditions. The Enlightened One, Buddha, was Siddhartha Gautama prior to his journey to enlightenment and subsequent propagation of the Middle Way, shaping the Buddhist philosophy and its various sects.

This series intends not only to explore their separate histories and impacts but also to provide a comparative perspective on their lives, teachings, the faith systems they initiated or influenced, as well as their enduring relevance in contemporary discourse. This exploration will be underpinned by a recognition of the need to understand these figures both in their own historical contexts and through the eyes of their followers.

A deep dive into the lives and legacies of these paramount agents of spiritual and cultural change promises a journey of thought-provoking reflection on historical shifts, sociocultural formations and transformations, inextricably tied to their teachings. As we embark on this exploration, let us recognize that through their legacies, these figures provide insights into the deep tapestry woven into humanity's collective spiritual journey.

Welcome to the Philosophy Podcast series, fellow seekers of wisdom. Today, we bring you another riveting episode, let's delve into the enigmatic world of the Philosophers Who Shaped the World: Plato, Nietzsche, and Foucault. A journey across eras, dominated by the towering intellect of masters of thought.

Among all academic disciplines, philosophy holds a unique position - it's the compass that often directs the course of human thought. Studying philosophy is fundamental to understanding the world. It nurtures our curiosity, prompts us to question our purpose, probe the norms that shape society and dissect the layers of power that influences our lives. Beyond the confines of academia, philosophy seeps into our lives, often without us realizing it. Every decision, every stance is, in its own way, philosophical.

At the heart of this episode stand three iconic figures: Plato, the pioneering mind of ancient philosophy; Friedrich Nietzsche, the rebellious trailblazer of existentialism; and Michel Foucault, the radical voice of postmodernism. Each, in their own time and space, pushed the boundaries of thought and reshaped the contours of philosophy.

Plato, the pupil of Socrates and the teacher of Aristotle, forms the bedrock of Western philosophy. His insights on justice, politics, and knowledge continue to reverberate through centuries.

Nietzsche, the uncompromising critic of traditional values, confronted the existential void left by the decline of religion and offered new ways to affirm life.

Foucault, the audacious interrogator of power, and one often considered an intellectual heir to Nietzsche, disassembled the invisible structures that control knowledge and deconstructs the systems of societal surveillance imposed on individuals.

As we navigate through the episode, we shall first place each philosopher in the backdrop of their historical context. This will allow us to appreciate the cultural, social and political influences that sparked their philosophies. Following each contextual study, we will delve into their individual lives, exploring the experiences that nourished their intellect. From there, we shall examine their signature ideas, dissecting the bones of their contentions and absorbing the marrow of their insights. And finally, we shall evaluate their legacy, the impact they left on philosophy, and how their thoughts continue to influence contemporary issues.

In a confluence of ideas, we will attempt to draw threads between these three minds, observing the evolution of philosophical thought that spans over two millennia. Their ideas have had sweeping implications, rippling through social structures, art forms, and our understanding of the self.

Prepared for a deep dive into the intellectual universe of Plato, Nietzsche, and Foucault? Let us embark on this journey together and uncover the power of philosophy, understanding its substantial role in shaping the world - a tour de force that promises to be as fascinating as it is thought-provoking. Bring along your curiosity, and hold onto your existing beliefs lightly; they might just transform by the end of the journey.

Greetings and welcome to Masters of Art: Michelangelo, Picasso, and Warhol, an enthralling journey into the world of three trailblazers who have indelibly shaped the course of art.

Our purpose is three-fold: primarily to introduce each artist, their work, and the historical backdrop; probe into the profound impact of their oeuvres on successive generations; and instigate thought on how these masters embody the broader socio-political realities of their respective times.

Michelangelo Buonarroti, a seminal figure of the High Renaissance, was born in 1475 near Florence, Italy. He was a multi-skilled artist, acclaimed for his prowess in painting, sculpting, architecture, and poetry. Michelangelo remains etched in collective memory as an embodiment of High Renaissance ideals, his works radiating the splendor and grandeur of this period.

Fast forward several centuries, we come to Pablo Picasso, the flagbearer of 20th-century modern art. Born in 1881 in the Andalusian city of Málaga, Spain, Picasso was best known for his instrumental role in founding the Cubist movement and his unprecedented shattering of traditional boundaries within visual art.

The third focal point is Andy Warhol, the enfant terrible of the Pop Art movement who thrust the commonplace into the limelight. Born in 1928 in Pittsburgh, Warhol's provocatively banal imagery stirred heated debates about the nature and purpose of art in a consumer-driven, media-saturated post-war society.

Although separated by time and style, these artists share an unmistakable influence over the evolution of the creative world. Michelangelo’s devotion to humanism and naturalistic depiction laid the groundwork for western art and aesthetics. Picasso, defying convention, gave birth to a radical new visual language that challenged our perception of reality. Warhol, meanwhile, democratized art by diving into the ocean of mass culture and emerging with pearls that blurred the line between high art and everyday life.

Their significance extends beyond the realm of art into the wider world. Michelangelo's depictions of humanity came to represent the zenith of human potential, influencing cultural and social norms. Picasso acted as the lens through which the tensions of his conflict-ridden epoch could be seen and critiqued. Warhol, with his fascination for celebrity and commercial imagery, profoundly shaped the modern aesthetics of fame and consumer culture.

Today, we tie these threads together, initiating a discourse to explore the life and work of these three masters, each a cornerstone of a pivotal artistic movement. Our journey begins in the studios of Renaissance Italy, winding through the tumultuous birth of modern art in Spain, before alighting in the vibrant chaos of Warhol's New York. So settle in, as we trace the extraordinary paths of Michelangelo, Picasso, and Warhol - a triad of luminaries who have forever changed the artistic landscape. Their captivating stories beckon us; let's step into their world.

Greetings, dedicated lovers of literature and curious minds! Today, we embark on an insightful journey - a voyage in the extraordinary literary cosmos of our civilization, piercing through time, culture, and consciousness to appreciate and absorb the works of three colossal figures in the canon of world literature. These are the titans whose creative genius has shaped narratives, challenged societal norms, and revolutionized storytelling. I welcome you to our podcast series "Titans of Literature: Homer, Shakespeare, Tolstoy."

Literary giants are not born from thin air. They are products of their own societies, epochs, and cultures which contextualize their thoughts and creations. Homer, the mysterious bard of antiquity who bequeathed to us the grandeur of "The Iliad" and "The Odyssey". Shakespeare, the nimble wordsmith from Stratford, whose sonnets and plays celebrate the human condition in all its fantastic complexity. Tolstoy, the contemplative count of nineteenth-century Russia, whose weighty novels, "War and Peace" and "Anna Karenina", mark the apex of realist fiction. Each, in turn, engraved profound imprints on the face of literature, leaving enduring legacies that have transcended borders and epochs, persisting in their relevance today.

These stalwarts of the written word have not merely created masterpieces that decorate the highest shelves of our literary edifice. They are the embodiment of the power that literature holds over humanity, moving not just hearts, but civilizations. Their creative output, shrouded in beauty, insight, and emotional depth, allows us an intimate connection to the human experience across time and space.

Our journey today will take us through the spectacular trajectories of these three literary giants. We'll delve into their influential lives and the socio-political climates that nurtured them. We'll unlock the startling grandeur and profound humanity in their unparalleled narratives. We'll trace their incalculable impact through the historical corridor, unveiling how these titans continue to shape our thought, culture, and understanding of the human heart, even centuries after their quills have fallen silent.

Finally, we'll engage in comparative analysis, discerning the symbiotic connections and divergence between these colossi. The intellectual landscape of Ancient Greece, Elizabethan England, and 19th-century Russia will be laid bare, as we decipher how their civilizations and personal philosophies fashioned the extraordinary fabric of their narratives.

The legacies of Homer, Shakespeare, and Tolstoy endure, their works continuing to resonate, inspire, and challenge. Through their writing, we unearth the depths of our own humanity and are transported into other worlds, consummating a deep bond with these towering figures of literature who continue to converse with us across the chasm of time.

Embarking on this voyage, my dear listeners, we are not merely learning about literature. We are uncovering life itself - the passions, struggles, and triumphs that form the collective human experience in its most beautiful articulation. So, hold tight as we launch into this thrilling exploration of the titans of literature, whose immense shadows dominate the landscape of narrative and storytelling. This intellectual adventure promises to be one of charismatic charm, profound insight, and perpetual wonder.

Before we delve into the lives of Galileo Galilei, Sir Isaac Newton, and Albert Einstein — extraordinary men who changed science and the world — we must first set the stage for the scientific revolution they each ushered into existence. We're journeying back to a time when the world operated on a vastly different understanding of the universe.

Our exploration begins in the pre-scientific world, a time when prevailing knowledge was dictated by religious texts, philosophical discourse, and sparsely developed naturalistic observations. The Earth was believed to be at the universe's center, and celestial bodies were interpreted as immaculate, unchanging spheres traveling in perfect circles. Our ancestors carved reality from their observations and beliefs, underpinned by religion rather than empirical evidence.

However, the socio-cultural landscape began to change dramatically with the advent of the Renaissance and the Reformation. The period of the Renaissance, with its renewed interest in classical knowledge and humanistic ideals, prompted a wave of intellectual curiosity across Europe. The polymaths of the era — like Leonardo da Vinci — were filled with curiosity and started questioning the pre-existing doctrines.

Among these figures, we find the pioneers who sought to pull back the mysterious curtain of the universe and peek into its mechanics: Galileo, Newton, and Einstein. Not content with relying purely on ideological constructs, they experimented, questioned, and deduced the fundamental rules that governed the world around them.

At the same time, the Reformation in the church affected society profoundly. It challenged the establishment's authority, encouraging people to question long-held beliefs. This cultural shift mirrored scientific developments, further shaking societal foundations and paving the way for innovative thought.

As the scientific revolution unfurled, elaborate philosophical arguments gave way to the empirical study of nature. A new way of asking questions was born: experimental science. We moved from a time of speculative reasoning to studies based on experimentation, observation, and analysis. This rigorous scientific methodology would dissect the universe's previously accepted characteristics to reveal the startling, beautiful, and complex laws that truly governed existence.

Transitioning from an era rooted in the primacy of philosophical reasoning and religious doctrine, humanity stood on the precipice of a new epoch. Galileo, Newton, and Einstein's footprints were soon to be imprinted on the sands of time - the harbinger of cataclysmic shifts in our understanding of the cosmos.

In this revolution, men like Galileo, Newton, and Einstein were more than just participants; they were the architects. Today's episode will explore their lives, the tumultuous times they lived in, and their monumental contributions that forever reshaped our understanding of the universe. As we peel back the layers of their groundbreaking discoveries, we will see how each pioneer built on the foundations laid by their predecessors, pushing science forward and expanding the realm of human comprehension.

The study of history is not just the examination of dates, places, and events—it's an in-depth look into human behavior, motivations, and characteristics that shaped these events. At the center of many significant historical epochs, we find one common element: great leaders. These figures have left indelible marks on the fabric of their societies and, in many instances, on the world stage.

So, what defines great leadership? While the parameters may slightly shift depending on cultural norms and societal needs, some elemental components constitute a great leader. They are individuals who can strategize and enact plans that propel their societies towards improvement, battling against the odds to create transformative change. They possess the ability to influence, inspire, and guide others toward a common goal, often driven by a greater vision that extends beyond personal aspiration. They blend pragmatism with idealism, foreseeing immediate hurdles, and navigating them, yet firmly grounded in their transformative vision.

Attributes such as charisma, courage, intelligence, adaptability, and the ability to foster unity are salient within many esteemed leaders. But these characteristics may manifest in different combinations and to varying degrees, making each leader a unique blend. Alexander, for example, combined strategic intelligence with relentless courage, whilst Mandela paired an indomitable spirit with the power of persistent peace. This diversity illuminates the multi-faceted nature of leadership, affirming that there is no singular archetype for a great leader.

The significance of great leaders in history cannot be understated. While it is the collective who ultimately shape history—through wars, revolutions, the weaving of innovative ideas, and cultural strides—leaders serve as the linchpin. They not only guide these collective forces effectively but also often catalyze these movements. From Alexander building one of the largest empires of the ancient world to Mandela leading South Africa out of apartheid, their stories illuminate how essential leadership is in the consequential shifts in societies and civilizations.

These leaders' stories also humanize history, adding riveting narratives to what could seem, at first glance, merely an impersonal string of events. Their triumphs and failures, their virtues and vices, their ideals, and their actions allow us to delve deeper into understanding the human elements that shaped history.

Indeed, history cannot be fully understood without studying great leadership. Each leader from Alexander to Mandela provides us with differing brass tacks on the concept of leadership. Querying their actions, their motivations, and their impact not only helps us comprehend the past, but it should also guide us in assessing present-day leaders and framing our expectations for future leadership. Thus, as we venture into discussing these unique profiles of leadership—beginning with Alexander the Great and culminating with Nelson Mandela—our journey will be illuminating, instructive, and insightful.

Let us embark on a fascinating journey into the realm of faith and belief, an exploration of major world religions and their profound impact on human civilization. Today, in the continuum of human experience, religion is a touchstone, shaping societies, molding individual identities, and etching ethical and moral frameworks that govern conduct, both personal and public.

Before diving into this exploration, it is crucial to understand what we mean by ‘religion’. The Oxford Dictionary defines it as a particular system of faith and worship, but does this encapsulation fully grasp the complexity of religion? Religion is more than a system or a set of rituals; it is a multifaceted phenomenon intertwining faith, worldviews, traditions, ethics, and social organization. It is a deep and profound expression of humans' desire to understand the universe, its existence, and the very meaning of life.

Religion has a pivotal role in human experience - serving as a backbone of societal structure, a source of solace and inspiration, a mechanism for making sense of the world, and a compass guiding human behavior. It offers a sense of community, identity, and purpose, threading together individuals into a shared fabric of beliefs and practices. In essence, religion plays a critical role in shaping the intricacies of human civilization and progress.

Let's briefly skim the surface of the major world religions we'll delve deeper into.

Hinduism, an ancient faith from the East, counts a significant percentage of the world’s population as followers, mainly in India and Nepal, and threads through a rich tapestry of beliefs, practices, and a pantheon of Gods.

Buddhism, the middle path, emphasizes on cessation of suffering and reaching a state of enlightenment, Nirvana, through moral conduct, concentration, and wisdom.

Judaism, a monotheistic faith, forms the bedrock of western religious thought and asserts a covenantal relationship between God and his chosen people, the Jews.

Christianity, rooted in the life and teachings of Jesus Christ, centers on concepts of love, grace, and redemption, and is the world's most widely practiced religion.

Islam, prescribing submission to the will of God, follows the teachings of the Prophet Muhammad, prophetically culminating Abrahamic religions.

Sikhism, with its message of equality and justice, crystallizes the teachings of Guru Nanak and successive Gurus into a monotheistic faith.

Daoism and Confucianism, not strictly religions in the Western sense, are moral philosophies that have shaped societal structures and thought patterns across East Asia.

Alongside, we have myriad indigenous and tribal religions, modern faiths like the Baha’i, Jainism, and syncretic movements like the Rastafari that broadened the religious landscape, each adding its unique flavor.

Our exploration, however, transcends the boundaries of traditional faith. Atheism and agnosticism, gaining considerable traction in contemporary societies, question religion's very foundation.

Indeed, the world of religion is not a monolith but a spectrum, a rainbow of beliefs and practices, each lending color to the human experience in its unique way. As we navigate this journey, may we gain insights into not only the religions themselves but also the indelible mark they leave on societies, cultures, and individuals across the world. Buckle up; it's going to be an enlightening ride.

Eastern Philosophy, a quadrant of intellectual thought and cultural influence, summarizes millennia of sophisticated introspection, spiritual exploration, and profound wisdom from civilizations rooted in the far East. The mystical aura surrounding Eastern philosophy emanates from its sublime diversity, probing introspection, and holistic worldview that innately, albeit distinctively, differs from the philosophies of the Western Hemisphere.

Distinctively, Eastern philosophies are characteristically spiritual, placing paramount emphasis on understanding the metaphysical realm, the pathway to enlightenment, and the ethical practices necessary for spiritual growth. Eastern philosophy juxtaposes the materialistic and utilitarian approach of Western thought—Eastern traditions often focus on the inner self and its universe, emphasizing harmony, spiritual liberation, and integral unity of all existences, showcasing its unique metaphysical perspective.

Furthermore, these philosophies exhibit a holistic viewpoint, viewing reality as an interwoven network of relations rather than a sum of segregated parts. This comprehensive approach promotes harmony and balance, considering individual actions and societal structures inseparable from the cosmic order and spiritual ethics. Moreover, Eastern philosophy often incorporates practices like meditation and mindfulness, linking intellectual thought to practical discipline for spiritual growth—an amalgamation rarely found in Western intellectual traditions.

Moreover, Eastern philosophies, encapsulating ideologies like Confucianism, Buddhism, and Hinduism, have exercised profound influence throughout the ages. Primarily originated in China and the Indian subcontinent, these philosophies, their moral principles, and spiritual practices constitutively shaped East Asian and Indian civilizations. Up to the present day, they remain influential, significantly impacting societal norms, art, literature, and governance systems in these regions.

Conversely, these philosophies have transcended geographic and intellectual boundaries, engaging global minds, and challenging Western paradigms. The compassionate ethos of Buddhism, balancing wisdom of Taoism, rigorous ethical system of Confucianism, and profound spirituality of Hinduism have resonated across continents, modifying the course of human thought, and inspiring an array of intellectual, artistic, and scientific movements in the West.

However profound, Eastern philosophies aren't mere confinements of the past; they remain an inclined heartbeat within their native societies, continually impacting international sociocultural landscapes, and global intellectual discourse. In the modern age, where society reels under materialistic obsession, alienation, and environmental degradation, Eastern philosophy's wisdom may indeed pave the path towards a more harmonious, holistic, and balanced future.

Above all, the true essence of Eastern philosophy lies in its cerebral approach to life's fundamental questions, spiritual guidance, and the facet of shared humanity, offering a valuable alternative perspective to the human condition. This historical corpus of Eastern Thoughts is not merely a contrasting worldview but rather a bridge spanning humanity's intellectual heritage, binding us closer than ever before. In the forthcoming exploration, the cultural richness of Eastern philosophies will be unfolded, expressing the depth and diversity of ideas that have guided civilizations for millennia.

Our exploration of 20th Century Philosophy today takes us into the heart of existentialism, a major philosophical movement that has shaped our contemporary understanding of human freedom, subjectivity, and the meaning of life.

To begin, let's introduce existentialism. Drawing on its Latin roots, 'existentialism', broadly defined, refers to the philosophy focused on existence, specifically, human existence. Unlike many other philosophical schools, existentialism does not emphasize a systematic theory, but rather confronts the illogical, paradoxical, and subjective aspects of human life.

The origins of existentialism can be traced back to the 19th century, more specifically to Danish philosopher Soren Kierkegaard and German philosopher Friedrich Nietzsche, although the term "existentialism" did not come into official use until the 20th century with Jean-Paul Sartre. Both Kierkegaard and Nietzsche were concerned with subjective human experience and critiqued the abstract rationalism of their contemporaries.

Now let's delve into the main themes of existentialism. Perhaps the quintessential existentialist axiom is Sartre’s phrase "existence precedes essence." By this, existentialists mean that humans first exist and only then, through their actions and choices, define who they are. This assertion emphasizes the fundamental freedom of the individual but also the accompanying responsibility, revealing the inherent tension of existentialist thought.

Another key existentialist theme revolves around absurdity and despair. Here, life, devoid of any predetermined meaning or purpose, is seen as absurd. The realization of this absurdity can lead to despair—a profound existential crisis— but also, paradoxically, to the potential for authentic living.

A third theme in existentialist thought pertains to authenticity and bad faith. Authenticity involves acknowledging the absurdity, freedom, and isolation of one's existence and embracing the resulting responsibility. On the contrary, bad faith involves self-deception, denial of freedom, and evasion of responsibility.

Importantly, existentialism also provides a critique of societal conventions and institutions that limit human freedom and authenticity. This critique led to diverse applications of existential thought, influencing not just philosophy but also literature, arts, and psychotherapy.

It is important to remember that existentialism is not about hopelessness or nihilism. Despite its sober view of existence, at its heart, it affirms the possibility of creating meaning and value in an indifferent universe. Though hinging on high intellectual discourse, existentialism at its core is remarkably accessible—it asks, and attempts to answer, timeless questions about the human condition, questions we all grapple with in our quiet moments. Thus, existentialism remains a profoundly influential force in our modern philosophical landscape, compelling each of us to confront our existence and search for authenticity in our individual paths.

Georg Wilhelm Friedrich Hegel, a celebrated figure in 19th century philosophy, was born in Stuttgart, Germany in 1770. Coming from a religiously inclined family of modest means, Hegel found himself immersed in theological studies from an early age, a training that would later provide substantial fodder for his radical philosophical ideas.

As a career academic, Hegel meandered his way through various universities. He started his intellectual journey at Tübingen Seminary, an academic institution renowned for fostering some of the brightest minds of the time, including Friedrich Hölderlin and Friedrich Wilhelm Joseph Schelling, both of whom later became notable figures in German idealism. This intellectual trifecta shared what could be called a philosophical marathon, endorsing knowledge over faith and tossing revolutionary ideas on epistemology back and forth.

In 1801, Hegel moved to Jena, a city that set the stage for his ascendancy in the philosophical world. Working as an unsalaried lecturer while living barely above the poverty line, Hegel found the impetus for his most iconic philosophical works. His life at Jena culminated in the completion of his opus "The Phenomenology of Spirit" in 1807, where he introduced his dialectical method of arriving at truth — Thesis, Antithesis, and Synthesis.

Hegel’s life was at the mercy of a tumultuous political and social backdrop, marked by the French Revolution and the Napoleonic Wars, events that culminated in the creation of the modern state system. The political zigzags of his time were imprinted in his theories, particularly in his Philosophy of History. He proposed the idea of an "Absolute Spirit", a universal consciousness that progresses through conflicts and contradictions, consequently influencing the course of history.

A champion of the State, Hegel believed that it was the earthly embodiment of the Absolute Spirit, an idea which would come to be exploited by totalitarian regimes of the 20th century. His magnum opus, "Science of Logic", called for a reconciliation of individual freedom with the requirements of community in the modern state, a subject matter relevant even in the context of today's political spectrum.

Hegel's influence on the philosophical world was substantial in scope, influencing luminaries like Karl Marx and Friedrich Engels, which led to the birth of Marxism. At the same time, his writings elicited strong criticisms, especially from existentialist philosophers like Sören Kierkegaard and Friedrich Nietzsche, who would later star in our podcast series.

Hegel’s academic career saw its peak upon his appointment as the Rector of the University of Berlin in 1829, a station he retained until his sudden death from cholera in 1831. His death marked the end of an era for German Idealism, but not an end to his influence which continues to unravel in contemporary debates on politics, history, and philosophy. Spanning across systems of thought and across centuries, the oeuvre of Hegel remains a beacon guiding philosophical discourse even today. Let's delve deeper into his primary ideas in the next sections.