Preface: This piece was co-written by ChatGPT and me. But let me be clear—I spent a hell of a lot of time revising what it wrote. So I’m claiming at least half the credit.

Notes for myself:

• Trier: One of the oldest cities in Germany and the birthplace of Karl Marx, located in present-day western Germany near the Luxembourg border.

• Kingdom of Prussia: One of the most powerful German states in 18th–19th century Europe, known for its militarism and bureaucratic system. Marx spent his youth under Prussian rule.

• German States: In the 19th century, what we now call “Germany” was not yet unified, but made up of dozens of independent, German-speaking principalities. They were unified only in 1871 under Prussian leadership.

• Lutheranism: A major branch of Protestant Christianity stemming from Martin Luther’s Reformation. It emphasizes salvation through faith. Marx’s father converted from Judaism to Lutheranism to assimilate into Prussian society.

• University of Bonn: A prestigious German university. Marx enrolled at 17 to study law, but was more interested in philosophy, literature, drinking, student societies, and even dueling.

• Dueling: A common practice among 19th-century European students to defend personal honor—often with swords or pistols. Marx took part in one, which shows a rebellious streak.

• Humboldt University of Berlin: A major intellectual hub in Germany, where Marx delved deeply into philosophy and first encountered Hegel’s ideas.

• German Classical Philosophy / German Idealism: A major philosophical movement from the late 18th to early 19th century, with figures like Kant, Fichte, and Hegel. It emphasized reason, freedom, and historical development. Profoundly influential on Marx’s own thinking.

• Humoral Theory originated with ancient Greek physicians Hippocrates and Galen. It held that the human body was composed of four bodily fluids: blood, yellow bile, black bile, and phlegm. Health was seen as the balance among these four humors, while disease resulted from their imbalance. This theory dominated medieval medicine, advocating treatments such as bloodletting and induced vomiting to “adjust” the humors. It remained influential until William Harvey’s discovery of the circulatory system gradually displaced it.

• Two Treatises of Government, published by John Locke in 1690, is one of the most important works of political philosophy from the Enlightenment. The first treatise refutes the idea of the divine right of kings. The second introduces several key concepts: Natural rights: life, liberty, and property; Social contract: government derives its authority from the consent of the governed; Right of revolution: people have the right to overthrow tyranny. This work laid the foundation for liberal political theory and had a profound influence on the American Revolution and the French Revolution.

• Critique of Pure Reason, published by Immanuel Kant in 1781, is a monumental philosophical work that marks the beginning of the German classical philosophical era. Its central question is: How is knowledge possible? Kant argued that knowledge is not a passive reception of experience but a synthesis of experience and the mind’s rational structures. The book established his system of transcendental philosophy and became a turning point in modern philosophy.

• Transcendental Philosophy is the philosophical method proposed by Kant. “Transcendental” does not refer to something mystical, but to the a priori conditions that make cognition possible. Kant believed that our capacity to know the world presupposes certain innate forms (such as time and space) and categories (such as causality and quantity). These structures do not come from experience; rather, they are the way in which experience becomes possible. This is what Kant called the “Copernican turn.”

• Philosophy of Nature is a concept developed by Schelling. He argued that nature should not be seen as a passive object but as something imbued with spirit and creative force. He sought to overcome the traditional oppositions of subject vs. object and spirit vs. matter, proposing that nature and consciousness are unified at a higher level. His philosophy of nature served as a bridge between Romanticism and scientific thought, and it significantly influenced later ecological philosophy.

• Aufhebung, often translated as “sublation,” is a core concept in Hegel’s dialectics. The German word Aufhebung simultaneously means negation (cancellation), preservation (maintenance), and elevation (transcendence). It describes the developmental process of things: one stage encounters contradiction, is negated, but its rational content is preserved and then transcended at a higher level. In simple terms, “negation of the negation” does not mean destruction, but transformation into a higher form.

• Absolute Knowledge appears in the final stage of Hegel’s Phenomenology of Spirit. It does not mean knowing all facts or possessing total information. Rather, it refers to the realization that the world is not something external, but a structure that unfolds through the activity of the self in practice and history. In other words, knowing is no longer about observing the world, but about creating it. Truth is not a fixed, external standard but the evolving totality produced through the interaction between consciousness and reality.

1-0: Karl Marx

In 1848, The Communist Manifesto was published. Marx and Engels penned the rallying cry: “Workers of the world, unite!” Although it had little impact at the time, it laid the theoretical foundation for future revolutions.

Karl Marx was born on May 5, 1818, in Trier, a city in the German states under Prussian rule. His father was a Jewish-born lawyer who had converted to Lutheranism; his mother came from a Dutch-Jewish family. Marx was raised in a well-off middle-class household—not rich, but comfortable. He was immersed in Enlightenment ideas from an early age and was familiar with religion, philosophy, and classical literature. At the time, “Germany” was not a unified nation. The German Confederation consisted of 39 sovereign entities: kingdoms, duchies, electorates, and free cities. Among them:

• Kingdom of Prussia: The dominant military-industrial power in the German lands, ruled by the Hohenzollern dynasty. It would later spearhead German unification.

• Austrian Empire: A multi-ethnic empire ruled by the Habsburgs, the most powerful force within the Confederation and beyond.

• Kingdom of Bavaria: A conservative, Catholic kingdom in southern Germany, known for its rich cultural traditions and regional pride. Capital: Munich.

• Kingdom of Saxony: A cultural powerhouse in eastern Germany, known for its craftsmanship and for Dresden, the “Florence on the Elbe.”

• Kingdom of Hanover: A mid-sized power in the northwest. Once shared a monarch with Britain but began independent rule in the 1840s—later absorbed by Prussia.

• Kingdom of Württemberg: Located in the southwest, balancing agriculture and industry. Politically, it often maneuvered between Prussia and Austria. Capital: Stuttgart.

Kingdoms, duchies, electorates, and free cities had different ranks:

• Kingdoms (Königreiche): Ruled by kings, with large territory and strong military.

• Duchies (Herzogtümer): Ruled by dukes, generally smaller and often subordinate to greater powers.

• Electorates (Kurfürstentümer): Nobility with the right to vote for the Holy Roman Emperor, enjoying elevated status.

• Free Cities (Freie Städte): Cities like Hamburg and Bremen, directly under imperial authority with high degrees of autonomy.

This fragmented power structure made Germany a patchwork of complex jurisdictions—a bit like the autonomous regions, municipalities, and special zones in early PRC. And just like in China today, local disputes never really stopped.

Judaism is one of the world’s oldest monotheistic religions, meaning it worships one (or more) supreme deities—like Judaism, Christianity, and Islam do. It emphasizes the sovereignty and creative power of God. Unlike Christianity, which emphasizes faith and redemption through belief in Jesus (especially in Protestantism), Judaism centers on law(mitzvot), covenants with God, and communal responsibility. “Salvation by faith” is not the core of Judaism—it’s a Protestant logic (especially Lutheran). In Judaism, what matters is not what you believe, but what you do. Judaism is thus not only a religion but also an ethnic and cultural identity. In the Jewish tradition, Jewish children are born into the covenant, which caused tension with other religions, as non-Jews wanted in on the “chosen people” deal. Christians recognize the Old Testament too, but that’s where the common ground largely ends.

Karl Marx’s father, Heinrich Marx, came from a long line of rabbis (Jewish religious teachers and legal scholars, often akin to bureaucrats or public intellectuals). But just before Karl was born, Heinrich converted to Lutheranism—not out of spiritual conviction, but because of institutional discrimination. In early 19th-century Prussia, Jews were barred from holding many public offices, including being a lawyer or judge. As a well-educated legal professional, Heinrich would have lost his career if he had clung to his Jewish identity. He wasn’t particularly religious anyway—more aligned with Enlightenment rationalism, viewing religion pragmatically and even critically. You could say: his body was in Cao camp, but his heart remained in Han("人在曹营心在汉").

At age 17, Marx enrolled in the University of Bonn to study law—but preferred poetry, drinking, and sword duels (yes, he had actual duel records). Later, he transferred to the University of Berlin, where he immersed himself in German Classical Philosophy, especially the works of Hegel.

1-1: The Enlightenment

The relationship between the Enlightenment and German classical philosophy can be understood as one between a “matrix” and its “mature form”: the Enlightenment provided the foundational ideas and problem consciousness, while German classical philosophy deepened, responded to, and transcended those problems.

The Enlightenment began around the latter half of the 17th century, when most European countries were still under absolute monarchy. Louis XIV of France likened himself to the sun, because just as the sun is the center of the universe, governing day and night and the seasons, he considered himself the center of the nation, around whom all of France revolved. He famously said, “L’État, c’est moi” (“I am the state”), expressing the divine right of kings and absolute royal authority. Through centralization of power, suppression of the nobility, control of local parliaments, and the strengthening of the bureaucratic system, he turned France into the quintessential example of European absolutism. He made laws, decided wars, appointed ministers—parliament had almost no power. He also built the Palace of Versailles, not just as a lavish residence, but as a political tool to draw nobles to the court and entangle them in elaborate rituals, thus weakening their regional influence. Simultaneously, through art, theater, architecture, and ballet, he shaped his image and instilled the sanctity of the “Sun King” into the minds of the people. His era became the golden age of classical French culture.

Meanwhile, the Catholic Church and national Protestant churches still held authority over education, morality, and the interpretation of truth, forming a powerful religious hegemony. Any thought that deviated from orthodox doctrine was suppressed—for instance, Galileo was put on trial for supporting heliocentrism. In such a system, knowledge was confined within theology, and the world was interpreted as a manifestation of “divine will” rather than governed by natural laws. Reason was treated as subordinate to faith, individual thinking was stifled, and questioning was seen as dangerous. Yet it was precisely this intellectual suppression and monopoly of power that pushed some thinkers to reflect and resist. They turned to reason, observation, and experience as new sources of truth, seeking to break free from the dual control of religion and monarchy. This impulse toward exploration marked the eve of the Enlightenment’s eruption.

At the same time, the Scientific Revolution was gaining momentum. Nicolaus Copernicus’s De revolutionibus orbium coelestium (On the Revolutions of the Celestial Spheres), published in 1543, was one of the foundational works of the Scientific Revolution—and also his final work, published as he was near death. Copernicus, a Polish astronomer, clergyman, and mathematician, never married and held a church post while quietly pursuing astronomical studies. In the Middle Ages, the geocentric model was widely accepted in Europe. This view not only stemmed from ancient Greek traditions but also aligned with the Biblical worldview that placed Earth at the center, and thus was upheld by the Catholic Church. Although Copernicus had written the theory, he published cautiously—likely because he was a clergyman himself. In his book, he used the word “hypothesis” to avoid directly challenging church authority. A younger astronomer, Andreas Osiander, even wrote a cautious preface claiming the model was merely a “computational tool.” For these reasons, Copernicus’s theory didn’t cause an immediate stir. It wasn’t until the 17th century, when Galileo confirmed heliocentrism through observation and publicly challenged the Church, that the theory was officially condemned as heretical.

Galileo Galilei observed irregularities on the Moon’s surface and Jupiter’s moons through a telescope—findings that directly challenged the Church’s geocentric model and Biblical cosmology. He supported Copernicus’s heliocentric theory, arguing that the sun, not the Earth, was the center of the universe. As a result, he was tried and forced to publicly recant. Johannes Kepler proposed the three laws of planetary motion, proving that planets move in elliptical, not perfect circular, orbits. This shattered the ideal of “divine perfection” in celestial movement and emphasized that cosmic order could be mathematically described.

William Harvey, a 17th-century English physician, through systematic animal dissections and live experiments, was the first to fully describe the circulatory system, showing that the heart pumps blood throughout the body like a machine. This discovery undermined the ancient Galenic theory of the “four humors,” which claimed that health depended on the balance of bodily fluids. Harvey’s work marked the rise of empirical anatomy and experimental medicine. Robert Boyle, an English chemist known as the “father of modern chemistry,” rejected the mystical notions of matter found in alchemy. Through rigorous experiments, he studied the properties of gases and proposed the famous Boyle’s Law (inverse relationship between pressure and volume). He emphasized repeatable experiments and verifiable results, helping standardize scientific methods and deeply influencing the development of physics and chemistry. And finally, Isaac Newton—arguably the pinnacle figure of the Scientific Revolution—published Philosophiæ Naturalis Principia Mathematica in 1687, systematically presenting the laws of motion and universal gravitation. He used mathematics to explain celestial and terrestrial motion, marking the first time the universe was seen as a predictable, calculable “mechanical system,” free from mysticism and theological domination. Newton laid the foundation of classical physics and pushed the Scientific Revolution to its peak.

With the scientific groundwork laid, philosophy also began to flourish. In 1690, John Locke published Two Treatises of Government. Locke, an English philosopher, proposed the concepts of natural rights (life, liberty, and property), the social contract, and the people’s right to overthrow tyranny. These ideas directly challenged the divine right of kings and feudal absolutism, becoming the foundation of later liberalism and democratic institutions. His political philosophy is considered the cornerstone of Enlightenment political theory, deeply influencing the American Revolution and the French Revolution.

Between 1751 and 1772, Denis Diderot edited the Encyclopédie, one of the most iconic publications of the 18th-century French Enlightenment. Co-edited with mathematician Jean le Rond d’Alembert, the project spanned 28 volumes. On the surface, the Encyclopédie aimed to compile knowledge across all human disciplines—mathematics, astronomy, medicine, mechanical arts, literature, philosophy, music, fine arts, and political institutions. It was among the most ambitious publishing projects of its time and featured contributions from Enlightenment giants such as Voltaire, Rousseau, Montesquieu, and Holbach. It democratized knowledge and, through the dissemination of that knowledge, challenged the existing order—especially the Catholic Church’s spiritual monopoly. At the time, knowledge was a tool controlled by the clergy, nobility, and monarchy. Ordinary people had almost no access to an accurate understanding of the world. The Encyclopédie symbolized the emerging ideal that “knowledge belongs to everyone.” It presented complex academic, scientific, and artisanal knowledge in accessible form, allowing readers to gain cognitive independence rather than rely on priests or traditional authorities. This decentralization of knowledge was a direct embodiment of the Enlightenment’s central belief: human beings should achieve freedom through their own reason. Because of its strong anti-clerical and anti-feudal content, the Encyclopédie was banned several times by the French government and the Catholic Church. In 1752, the Church accused it of “spreading heretical ideas,” and publication was halted. Diderot faced threats of imprisonment, and the final volumes were printed in secret. Its very publication became a practical act of resistance against feudal authority. The Encyclopédie circulated widely in France and influenced intellectual and political thought across Europe, sowing the seeds for revolutionary change.

In 1784, German philosopher Immanuel Kant published the essay What is Enlightenment?, widely regarded as the philosophical summation of the Enlightenment era. In the essay, Kant gave a piercing definition: “Enlightenment is man’s emergence from his self-imposed immaturity.” By “immaturity,” he did not mean lack of intelligence, but rather the willingness to let others think on one’s behalf—whether priests, monarchs, or institutions. Kant argued that this condition was not due to coercion, but to a lack of courage and will. He called on people to “dare to use your own reason!” (Sapere aude!)—a rallying cry for independent thought. People, he argued, must become the masters of their own minds and not blindly follow tradition, dogma, or authority. In the same essay, Kant also reflected on the tension between freedom and order, arguing that while reason should be free, it must be exercised in a gradual, rational way. He warned that unexamined or “radical Enlightenment” could lead to chaos or violence.

1-3: German Classical Philosophy

Kant is considered the founding figure of German classical philosophy. He sought to reconcile empiricism and rationalism by proposing a system of “transcendental philosophy.” In Critique of Pure Reason, he argued that our knowledge of the world does not arise purely from experience, but is shaped by the internal structures of human cognition, such as time, space, and categories. This view is known as the “Copernican turn,” meaning that it is not the mind that conforms to the world, but the world that appears according to the structure of our cognition. In ethics, Kant emphasized “practical reason,” asserting that human beings are free and autonomous moral agents who should treat others as ends in themselves, not merely as means. He also attempted to preserve a space for rational faith within religion. Kant was both a summarizer of Enlightenment ideals and a starting point for modern philosophy.

Johann Gottlieb Fichte (1762–1814) is often regarded as Kant’s successor, though he radicalized Kant’s idea of the “transcendental subject.” He claimed that the foundation of all knowledge, reality, and morality is the self (Ich). According to Fichte, the self posits itself and simultaneously posits the not-self. This self is not only the basis of cognition but also the source of creative action and the driving force behind the world. He emphasized the activity of the subject, free will, and a strong sense of historical mission, giving his philosophy revolutionary and nationalist undertones. Fichte developed a form of subjective idealism that paved the way for the more systematic philosophies of Schelling and Hegel.

Friedrich Wilhelm Joseph Schelling (1775–1854), who began from Fichte’s ideas, eventually moved beyond the self-centered model. He argued that the world cannot be understood solely from the standpoint of the subject, and that nature itself possesses spirit and creative power. He proposed a “philosophy of nature,” claiming that nature and spirit, object and subject, are unified at a higher level. This “philosophy of identity” views the world as an organic whole, rather than a dualistic division. He emphasized intuition, art, and the vitality of life, moving toward a philosophical style with romantic characteristics. Schelling’s ideas influenced Hegel and later existentialist and ecological thought.

Georg Wilhelm Friedrich Hegel (1770–1831) represents the culmination of German classical philosophy. He constructed a grand system of “absolute idealism” and attempted to explain the evolution of the world through dialectical logic. For Hegel, reality is not a static entity but a dynamic process unfolding through contradiction, conflict, and sublation (Aufhebung). This process applies not only to history but also to thought, art, religion, and the state. His dialectical method is often simplified as the triadic structure of thesis, antithesis, and synthesis, though more fundamentally it is the unfolding of self-consciousness.

The Phenomenology of Spirit (Phänomenologie des Geistes, 1807) is one of Hegel’s most important and complex works. Its structure can be understood as seven stages in the development of consciousness, with each stage overcoming and transcending the previous one, forming a spiraling ascent from experience to absolute spirit. The first stage, sense-certainty, represents the most immediate and raw layer of experience. Yet this level is full of subjectivity and ambiguity, and cannot provide stable knowledge. The next stage, perception, involves an effort to grasp the permanence of objects, though it remains trapped in the dualism of subject and object. The third stage, understanding, sees reason using abstract concepts such as causality to explain the world, but this leads to rigidity and formalism. When consciousness reaches the stage of self-consciousness, it no longer merely observes the world but becomes aware of its own subjectivity and begins to interact with the world. The most famous part of this section is the master–slave dialectic, which depicts a struggle for recognition between two consciousnesses, and the resulting power reversal. The fifth stage is reason, where consciousness believes that the world can be understood rationally, but gradually becomes aware of the limitations and contradictions of reason itself. This is followed by the stage of spirit, where consciousness moves beyond individual reason and enters the historical and social structures of family, society, and the state, within which the individual achieves a higher level of self-understanding. The final stage is religion and absolute knowledge. This last part is quite complicated, and I had to study it carefully just to grasp the general idea.

Absolute knowledge does not mean knowing everything or storing all facts in one’s mind. It means the realization that consciousness itself is the source of the world’s unfolding. In other words, I am not a detached observer analyzing an objective world. Rather, my identity is formed through the very process of encountering contradiction, engaging in practice, negating, and creating. Truth is not something already out there waiting to be discovered, but is continuously produced through the interaction between consciousness and the world. The observer and the observed co-create the concepts of self, world, and other. This actually resonates with some ideas in quantum mechanics.

We usually understand knowledge as: I am here, the world is there, and I observe it and try to understand it. At the level of absolute knowledge, consciousness finally realizes that the world is not an external object but the product of its own unfolding. My reason is not merely an eye to look at the world, but a force that shapes the world itself. All seemingly “external” realities—labor, language, institutions, history—are in fact expressions of spirit. The real world is the self-realization process of spirit.

Here is a simple metaphor. You can think of absolute knowledge as someone finally realizing that they are not just watching a movie, but are simultaneously the director, actor, script, audience, and camera. This person has not just learned a lot about how movies work—they have come to understand how the film is created by and through themselves. The divide between subject and object is overcome. Traditional philosophy maintains the opposition between subject (self) and object (world), thought and being, reason and reality. Hegel says this opposition is an illusion held by an immature consciousness.

This is radical, because it implies that truth is not an external God, a natural order, or an eternal law. Truth is the cumulative self-understanding of humanity, constructed through labor, history, culture, and philosophy. To know ourselves through our history and practice is, in essence, to know what people have long called God.

Under the influence of this philosophical system, Karl Marx wrote The Communist Manifesto.