Western Philosophy Timeline

May 1, 2025 | 9,842 words | 47min read

This is a timeline of the most relevant philosophers in Western philosophy. When I say Western, I mean continental Europe, parts of the Middle East, England, and later America.

The Pre-Socratics

This philosophical era is called “pre-Socratic” because of the importance of Socrates in Western philosophy, often thought of as a starting point for philosophy. All philosophers before him are included in this era.

626 BC – Thales
Summary:
Theorized that the ultimate substance of which everything is made is water — this idea is called monism. He was the first to reject myths and legends, seeking natural explanations behind events, and is often considered the inventor of philosophy. Stories say he was the first to create options and futures by buying up all the olive presses in town and renting them out.

610 BC – Anaximander
Summary:
Student of Thales. He believed that the first humans lived inside the belly of a fish, where they grew up until they were self-sufficient and then cut their way out. He also thought that multiple worlds existed, created by the so-called infinite (Apeiron).

570 BC – Anaximenes
Summary:
Student of Anaximander. He believed that the ultimate substance of everything was air. He thought water was just condensed air, and if condensed even further, it would become earth.

570 BC – Pythagoras
Summary:
Student of Anaximander. He believed the universe is made up of a combination of units — pure forms of matter — and these units are numbers. He was the first to describe himself as a philosopher (a lover of wisdom). He is also famous for his belief in reincarnation, and thus thought it immoral to eat animals, as they could be the reincarnation of a human.

540 BC – Parmenides
Summary:
Believed that everything has always existed: “from nothing comes nothing, and from something, nothing can come.” His big claim was that there is no real change — all of reality is one. He was the first to argue that reasoning is superior to the senses, bringing deductive reasoning into philosophy.

540 BC – Heraclitus
Summary:
Believed that everything in the universe is governed by the logos, a universal cosmic law, which he identified with change: “everything is in a constant state of flux.” That’s why one can’t step into the same river twice. He also believed that everything is shaped by opposites: “Day and night are just two sides of the same coin.”

490 BC – Zeno of Elea
Summary:
Student of Parmenides. Most famous for his paradoxes, designed to prove that there is no change. For example: How can a runner ever reach a goal if he must first reach the halfway point, then halfway of the halfway, and so on? (Not to be confused with Zeno of Citium, founder of Stoicism.)

490 BC – Empedocles
Summary:
Tried to reconcile the dispute between Parmenides and Heraclitus by saying both were right. He believed everything is made up of earth, air, fire, and water, which are fundamental and unchanging, but by combining these elements, change appears — birth and death are just human conceptions. He was the first to differentiate between force and substance.

460 BC – Democritus
Summary:
Developed a complete mechanistic view of the universe: everything is made of atoms and empty space. The atoms were small, indivisible particles, unchanging like Parmenides’ “being.” He believed there were infinitely many kinds of atoms making up all matter. This theory also beat Zeno’s paradox: you can’t infinitely divide the distance between the runner and the goal because there’s a smallest indivisible unit — the atom. He was the first materialist.

Socrates and the Sophists

These are all philosophers who lived around Socrates’ time or shortly after and were directly influenced by him.

470 BC – Socrates
Summary:
Socrates was famous for his Socratic method, in which he questioned various people on the street about philosophical matters, first appearing ignorant, then pointing out contradictions in their positions. It was said that he left people either angry because he made them feel stupid, or angry because he wouldn’t leave them alone. One philosopher put it like this: “Socrates was the first to bring philosophy down from the heavens and place it into homes and cities.” In the end, he made so many people angry that they put him on trial and sentenced him to death.
He was one of the first philosophers to ask, What is the good life? His answer: to gain peace of mind through living virtuously. He disputed the Sophists’ claim that morals are relative and instead believed that morals were objective. He thought the only way to live a virtuous life was by knowing what virtues are through rigorous investigation: “The unexamined life is not worth living.”
Socrates also didn’t believe in evil; he thought humans were simply misguided or missing knowledge. Thus: “There is only good — knowledge — and one evil — ignorance.”

470 BC – The Sophists
Summary:
Sophists were teachers who taught anything for the right price: rhetoric, music, mathematics, and more. They became important because of the need to win battles in court, but the Sophists didn’t teach true knowledge. Instead, they taught how to win arguments through rhetoric.
They were skeptics, refusing to accept claims just because reason seemed to support them; instead, they demanded hard proof, which for them was human experience. They rejected abstract ideas like those from Democritus or Empedocles.
The Sophists believed that the experience of all people is equally valid, meaning they embraced moral relativism: “Man is the measure of all things.”
“Nothing is inherently good in itself; something is only right because a person judges it to be right.”
Sophists would say they didn’t teach people more true knowledge but more useful knowledge.

430 BC – Plato
Articles: What is Love?, Euthyphro Dilemma
Summary:
Student of Socrates. He founded the first philosophical academy, which, in some form, survived for around 900 years.
Like Empedocles and Democritus, Plato thought that everything in the sensory world is in constant flux, but that there is still something infinite and unchangeable. For Plato, this unchanging reality was the Forms — leading to his famous Theory of Forms.
According to this theory, behind the world we experience with our senses exists another world: the world of Forms. While the sensory world is imperfect, the world of Forms is perfect and contains the patterns and archetypes of all things.
Plato believed we can understand these Forms not through our senses but through reason, and that the life goal of every philosopher should be to understand as many Forms as deeply as possible, shown vividly in the Allegory of the Cave.
Plato also believed that humans consist of two parts: the body and the soul. The soul is immaterial, immortal, and has always existed in the world of Forms. Since the soul is trapped in the human body, it feels longing for the world of Forms — this longing is what Plato called Eros (love).
Thus, love of another human, or art, or music, is really the soul longing for the perfect Forms behind those things.
Humans seek immortality either through their children or through achieving lasting fame — what he called “intellectual children.”
He also founded political philosophy by presenting his vision of an ideal state.

384 BC – Aristotle
Articles: Virtue Ethics from First Principles, Nicomachean Ethics: Action Theory
Summary:
Student of Plato. Aristotle was the first truly systematic philosopher, writing extensively on many subjects.
He disagreed with Plato’s Theory of Forms, arguing that the so-called “Forms” were not independent, pre-existing realities (a priori), but rather constructs of human cognition.
While Plato believed nature is merely a reflection of true reality (the Forms), Aristotle believed that Forms and ideas are human reflections of nature. As a result, he focused much more on everyday life than Plato did.
Aristotle was also much more empiricist, believing that there is no such thing as a priori knowledge — all our knowledge comes from experience.
He believed everything in the world, including humans, has a telos — a purpose or end it is meant to fulfill. For example, rain exists to nourish plants and animals.
Connected to this idea, he argued that every cause ultimately leads back to one primal cause, which he called the Unmoved Mover — the first cause that moves everything else but is itself unmoved and self-causing.
He also developed virtue ethics, believing that living a virtuous life is living a well-lived life. This belief is justified by the idea that everything has a telos, and the telos of a thing is what is unique to it and what it excels at — in the case of humans, virtue.

Hellenistic Philosophy

This time period begins with the conquests of Alexander the Great, during which Athens lost its leading position. During this era, Greek culture and language became dominant across all major kingdoms — Syria, Egypt, and Macedonia.

400 BC – Cynicism:
Key Figures: Antisthenes, Diogenes, Crates of Thebes
Articles: [Lucian], The Cynic
Summary:
The Cynics believed that the only thing that mattered for a life well lived was virtue. Everything else — wealth, power, social status — should be rejected. In that vein, they also rejected social conventions and engaged in public displays of non-conformity, such as urination, masturbation, or even sex in public, to shock and challenge societal norms.

300 BC – Stoicism:
Key Figures: Zeno of Citium, Chrysippus, Epictetus
Articles: Seneca on Trial: The Case of the Opulent Stoic, Ancient Greek Logic, The Cambridge Companion to the Stoics
Summary:
Inspired by the Cynics, the Stoics also believed that virtue was the highest good. However, unlike the Cynics, they did not reject worldly things like wealth or power — they viewed them with indifference. Having money was fine; not having money was also fine.
Stoicism developed an elaborate systematic philosophy. They believed that the universe was guided by a universal reason called the Logos, which consisted of an active principle acting upon a passive matter.
God was not seen as a personal agent but as a rational force identified with nature and the universe itself. Everything that happens — death, disease, change — follows the will of this divine Logos. Thus, humans should learn to accept their fate calmly and live in accordance with nature. For example, if one falls ill, one should not whimper but accept it serenely.

300 BC – Epicureanism:
Key Figure: Epicurus
Articles: Letter to Menoeceus, Principal Doctrines, Letter to Herodotus
Summary:
The Epicureans were the main opponents of the Stoics. They believed that pleasure was the highest good, not virtue. However, they taught that the highest pleasures were not found in indulgence, but in restraint.
Pleasure was understood broadly, including not just physical pleasures but also higher pleasures like friendship, art, and intellectual pursuits.
On death, Epicurus famously said: “Death is nothing to us, since when we are, death has not come, and when death has come, we are not.”
They believed in the existence of gods, but thought that the gods had no concern for the material world — they existed apart from human affairs.

270 BC – Neoplatonism:
Key Figures: Plotinus, Porphyry
Articles: Nature of God
Summary:
Neoplatonism built upon Plato’s theory of Forms, the Stoic idea of Logos, and mystical elements from the East.
They differentiated between the Nous (God), from which everything emanates outward, producing first the realm of Forms, then nature and all matter.
The farther something is from the divine Nous, the less divinity and goodness it possesses. Matter without a soul — like stones or water — is thus the farthest from God.
However, humans retain a spark of the divine within them and an innate desire to return to the divine source. Through practice and discipline, one can achieve a mystical experience in which the soul reunites with the Nous — this was seen as the ultimate goal of life.

Classical Rome

0 BC – Jesus
Summary:
Founder of Christianity. Jesus introduced two major developments in theology:

1. The shift from polytheism (the belief in multiple gods) to monotheism (the belief in a singular God), which brought many philosophical advantages. For example, the concept of one ultimate unmoved mover.
2. In the Greek tradition, the world was seen as something that could be explored through reason, and faith wasn’t highly emphasized. In contrast, Christianity introduced the view that God is fundamentally mysterious and cannot be fully understood by human reason. As such, faith became a virtue to strive for.

Christianity also brought a new worldview. The Greek tradition held a cyclical view of the world, where time repeats in cycles. Christianity, however, adopted a linear view of history: the world was created at the beginning of time, and someday it will all end with the Last Judgment. Additionally, in Christianity, there is no idea of an immortal soul separate from the body; instead, the flesh itself, the body, will be resurrected by God and made immortal.

Middle Ages

The medieval age began with the fall of the Roman Empire and was deeply shaped by Christianity.

350 CE — Augustine of Hippo:
Summary:
One of the most famous Christian theologians, Augustine, in his book Confessions, described a proto-archetypical story of a sinner’s journey toward redemption through Christianity. He also wrote extensively against what he deemed Christian heresies, two of the most important being Manichaeism and Pelagianism.

Manichaeism believed that, besides the Christian God, there was another god responsible for all the evil in the world. Augustine argued this belief was problematic because it removed human agency—people could always blame their wrongdoings on the evil god, making it morally fatalistic.

Pelagianism, on the other hand, believed humans could achieve perfection and grace on their own. Augustine thought this was equally problematic, as it demanded moral perfection without reliance on divine grace. Instead, he proposed a “middle way”: while virtuous actions are important, grace ultimately comes from God. This view later became the foundation of Catholic doctrine.

Augustine was also highly influenced by Neoplatonism and Platonic thought, believing that the theory of forms existed within the mind of God, and that evil is simply the absence of good.

1225 CE — Thomas Aquinas:
Articles: Ontological Argument and Apophatic theology
Summary:
Famous for his work Summa Theologiae, Thomas Aquinas sought to derive Christian doctrine through natural theology—that is, not directly from sacred texts, but by observing nature. His project can be seen as “Christianizing” Aristotle: unlike Plato’s influence on Augustine, where the divine was found in a realm of ideas, Aquinas, following Aristotle, looked to the natural world. Like Aristotle, Aquinas was extremely systematic in his approach.

His fundamental project was integrating the newly reintroduced Greek philosophical texts—especially Aristotle’s works, which had been preserved and transmitted through Arabic scholars—into a Christian framework, making them compatible with Christian theology.

1260 CE — Meister Eckhart:
Articles: A Commentary on the 9th Sermon of Meister Eckhart
Summary:
One of the most important Christian mystics, Meister Eckhart is most famous for his collection of sermons in which he describes his mystical experiences. He stands in stark contrast to the mainstream theory of Scholasticism of his day, as logic alone is not enough to understand God’s grace.

Central to his sermons is the idea that Eckhart speaks from the viewpoint of God, arguing that only when we step outside of time, space, and even logic can we gesture towards God.

If Aquinas is the greatest systematic theologian of Catholicism, then Meister Eckhart is the greatest anti-systematic theologian. His writing is very similar to Nietzsche’s, but unlike Nietzsche’s aphorisms, Eckhart’s points toward the divine rather than away from it.

Meister Eckhart makes a fundamental distinction between God and the Godhead. God can be seen as the creator who made everything around us, and we can talk about Him in a rough way. This God is dynamic: He began creation and is revealed in scripture. He is imminent. The Godhead, however, is the divine essence, which cannot be spoken about and is totally static. The Godhead is as far away from God as heaven is from earth; it is transcendent.

How can we account for experiences in which the object and subject break down, where grammar and language no longer work? All we can use is metaphors and imagery. Eckhart tries to talk about something that doesn’t fit into language, and when one speaks or communicates about these religious experiences, all one can use are inspired metaphors. These metaphors don’t directly tell us something about God, but they gesture toward Him, bringing within us some change or inspiration.

The big problem, with mystics, is that it’s hard to discern what they are truly talking about. They offer beautiful metaphors or imagery, but they can’t give us much more than that. But at the very least they make us think.

Renaissance and Age of Enlightenment

The Renaissance and Age of Enlightenment, spanning roughly from 1400 to 1700.

1483 CE – Martin Luther
Summary:
Founder of the Protestant movement. Luther wanted to distance himself from Christian doctrine because he saw the Church as misusing its power and going against scripture by selling indulgences. He sought to return to the origins found in the New Testament, emphasizing that the Church was no longer necessary to receive God’s grace. Instead, personal connection to God took precedence. His motto was “grace by faith and scripture alone.”
One can think of Luther’s ideas as a radicalization of Saint Augustine’s thoughts on human depravity — that humans can only await God’s grace. He rejected the scholastic tradition, such as the work of Thomas Aquinas, criticizing their attempts to reconcile Aristotelian reason with religion. For Luther, “reason was the devil’s whore.”
Luther shifted Christian doctrine from a focus on works to an incorruptible faith: salvation came not through actions, but through a change in the soul infused by God. It was no longer necessary to go to a priest to receive salvation; instead, he introduced the concept of the priesthood of all believers.
Through this doctrine, Luther was the first to move away from the corporate and communal identity of people toward a more individualistic one. This paved the way for later Enlightenment thinkers, shifting moral responsibility from the group to the individual — a trajectory that eventually led to the modern concept of human rights. Luther stands as a bridge between the medieval scholastic static-self and the modern idea of the rights of man.

1599 CE – Thomas Hobbes
Articles: Selected Chapters of Hobbes’ Leviathan
Summary:
Most famous for writing Leviathan, in which he argues about the nature of government and society. Hobbes believed the natural state of humanity is chaos — a “war of all against all.” Only through the establishment of an absolute sovereign, to whom all power is transferred, can peace and order be maintained.

1596 CE – René Descartes
Summary:
The most famous of the Rationalists, Descartes believed that knowledge is gained through reason. He was the first systematic philosopher of the Enlightenment era to incorporate the Renaissance’s new image of humanity into a coherent system addressing all major philosophical questions of his time.
A major contribution of Descartes was his theory about the relationship between the body and the soul. He argued for a strict separation between them — a view known as dualism.
Another key idea was his radical skepticism: the only certainty he could find was that he existed — “Cogito, ergo sum” (“I think, therefore I am”). From this starting point, he reasoned that the idea of a perfect being (a priori) must come from God, and thus God must exist.
Building on this, Descartes concluded that experiences we perceive clearly and directly must also be real — because a benevolent God would not deceive us.

1632 CE – Baruch Spinoza
Summary:
Another prominent Rationalist, Spinoza advocated for a critical reading of the Bible, taking into account the historical context of its creation.
He rejected Descartes’ dualism, proposing instead a monist philosophy: that there is only one substance, which he identified with both nature and God — a view known as pantheism, inspired by Stoic thought.
Spinoza’s most important work focused on ethics. He argued that everything that exists is either cogitatio (thought) or extensio (extension) — the two modes (modi) of existence.
Since everything operates according to natural laws and is completely deterministic, Spinoza concluded that human thoughts and actions are simply manifestations of nature — and thus of God.
However, Spinoza’s God was not a personal deity, but more akin to a force or natural law.
Because humans do not control their bodies or their thoughts, he argued, we lack free will. Everything happens out of necessity. Therefore, Spinoza advised viewing the world sub specie aeternitatis — from the perspective of eternity.

1632 CE John Locke
Summary:
Locke was the first empiricist, believing that we can gain knowledge only through our senses and experiences. As such, he rejected the notion of a priori knowledge. His most important work was An Essay Concerning Human Understanding, in which he describes how all thoughts and imagination are reflections of our sensory experiences. Prior to receiving sensory input, he claimed, the mind is like a blank piece of paper.
Based on our senses, we develop simple sense ideas, and through thinking and reflection on these ideas, more complex reflection ideas are created — these are made by piecing together simpler ideas.
Furthermore, Locke differentiated between primary qualities and secondary qualities: primary qualities include form, weight, movement, and number, while secondary qualities include things like sweetness, sourness, and colors such as green or red. Locke believed that people could generally agree on primary qualities, but not on secondary qualities, as they differ from animal to animal and from human to human.
Despite his empiricism, Locke did hold some rationalist views, believing that natural laws, foundational ethical principles, and the knowledge of God’s existence are innate to every human being.

1685 CE George Berkeley
Summary:
Berkeley was the third major empiricist, alongside Locke and Hume, and at the same time one of the earliest idealists. He believed that everything we can know comes through our senses, and that the world is exactly as we perceive it. However, he argued that what we sense is not made of matter or substance but of the will of God — in other words, reality is made of spirit.
God is intimately present within our consciousness and calls forth all the ideas and sensory experiences we have. Nature itself, in Berkeley’s view, is an expression of God, who is the sole cause of all existence.

1711 CE David Hume
Articles: An Enquiry Concerning Human Understanding and Other Writings: Sceptical doubts, David Hume and Empiricism
Summary:
Probably the greatest empiricist. Like Locke, he believed in composite ideas, arguing, for example, that things like angels do not exist independently but are combinations of simpler ideas like man and wings.
Hume was very radical in his criticism of metaphysical and religious works, famously writing:

“If we take in our hand any volume of divinity or school metaphysics, for instance, let us ask, ‘Does it contain any abstract reasoning concerning quantity or number? No. Does it contain any experimental reasoning concerning matter of fact and existence? No.’ Commit it then to the flames: for it can contain nothing but sophistry and illusion.”

Hume distinguished between impressions and ideas: impressions are direct perceptions of reality through our senses, while ideas are the memories of impressions. Both impressions and ideas can be simple or composite. Importantly, Hume emphasized that some composite ideas created by our minds do not correspond to reality (e.g., angels, Pegasus) and can lead to false beliefs about things that do not truly exist.
He also pointed out the problem of induction — that we cannot logically justify inductive reasoning and therefore cannot be certain that natural laws (like causality) will hold forever.
In ethics, Hume rejected the idea of inborn ethical natural laws. Instead, he believed morality was based on emotions: we help others or think killing is wrong because of feelings like compassion, not because of reason.
In works such as Dialogues Concerning Natural Religion, Hume argued that even if God exists, we cannot know anything about Him beyond the fact that He created the world. A priori knowledge of God is impossible because God is not bound by any logical axioms, and a posteriori knowledge reveals only that the world exists, without attributing any properties to God. Any attempt to describe God would limit His nature (e.g., saying a table is made of wood excludes it being made of steel).
Hume also influenced how we think about miracles, arguing that we should only believe in a miracle if not believing would require accepting an even greater miracle.
Through these ideas, Hume undermined the Enlightenment project of reconciling faith and reason — particularly deism — and laid the foundation for Romanticism, which chose faith over reason.

1724 CE Immanuel Kant
Media: No Country for Old Men
Summary:
Coming after the era of empiricism and rationalism, one of Kant’s major projects was to resolve the dispute between the two camps. He argued that both reason and sensory experience are crucial for gaining knowledge of the world.
Kant agreed with the empiricists that all knowledge originates in sensory experience, but he also argued that certain structures in our reason shape how we experience the world. He compared this to wearing colored sunglasses: the world itself remains the same, but the sunglasses (reason’s structures) tint everything we perceive.
One such innate structure, according to Kant, is that we perceive everything within time and space. Thus, time and space are not properties of the external world but of human consciousness. This means consciousness is not passive but actively shapes our experience.
Another inborn structure, Kant argued, is the law of causality, which, contrary to Hume’s doubts, exists not in the external world but within our reasoning.
Kant distinguished between das Ding an sich (the “thing-in-itself,” reality as it truly is, which we can never access) and das Ding für mich (the “thing-for-me,” reality as shaped by our consciousness). Therefore, there is a boundary to human knowledge we cannot cross.
For Kant, this is where religion enters: as a Protestant, he believed that only faith can cross the boundary of knowledge. He described belief in God’s existence as a practical postulate — something we accept because it is practically necessary, similar to an axiom in mathematics.
In ethics, Kant argued for natural laws of morality, which are inborn in every human, universal across all places and times. He called this the Categorical Imperative, a moral law that commands (“imperative”) unconditionally (“categorical”).
Central to the Categorical Imperative is the idea that we should act only according to principles we would want to become universal laws.
Kant believed that only when humans freely choose to follow moral laws do they truly exercise free will; otherwise, they are slaves to their desires, money, or egoism.
Importantly, Kant extended the Categorical Imperative beyond individuals to groups — families, clans, and nations — leading to ideas like the League of Nations, founded with Kantian moral principles in mind.

1770 CE Georg Wilhelm Friedrich Hegel –
Summary:
A German Romantic idealist philosopher. Central to Hegel’s thought is the notion of the world soul or world spirit (Weltgeist), which he understood as the sum of all human spirits and consciousnesses. Only humans, according to Hegel, possess spirit, and when he speaks of spirit, he means the life of humanity — our thoughts, our culture, our history.
Hegel rejected Kant’s idea of das Ding an sich (“the thing-in-itself”). For Hegel, all truth is subjective; all knowledge is human knowledge. The only truth is that which we experience through our subjective spirit. In other words, if, as Kant said, there is no way for us to experience the “thing-in-itself,” perhaps it does not even exist?
However, this leads to a danger: if only individual subjective experience exists, it could result in idealistic solipsism — the belief that only one’s own mind truly exists and everything else is a construction of the mind.
Hegel avoids this trap by proposing that the world is not constructed by individual minds but by a collective mind — the world spirit or Geist. This spirit can be identified with the divine or the unfolding rationality of the universe.

Unlike most philosophers before him who sought eternal, unchanging truths, Hegel rooted philosophy in history. He saw history as a dynamic, flowing process — like a river that constantly changes, so that while we cannot focus on a single static point, we can still understand the river as a whole.
For Hegel, reason is dynamic and evolves over time: what was once considered acceptable (like slavery) is now rejected, showing that truth itself progresses through history. This view sharply contrasts with Kant, who believed the a priori forms of knowledge were fixed and unchanging.
For Hegel, the historical development of reason — the unfolding of the world spirit — is a process of gradual awakening to self-consciousness, ultimately striving toward infinity and absolute knowledge.

A key concept in Hegel’s philosophy is the dialectical method. In this process:

• A thesis (an idea) arises.
• It encounters an antithesis (its opposite).
• From the conflict between them, a synthesis emerges, combining elements of both.

This dialectic drives the development of history and thought. For example, the thesis of rationalism faced the antithesis of empiricism, leading to the synthesis found in Kant’s philosophy.
Another example:
Being (thesis) vs. Nothing (antithesis) results in Becoming (synthesis).

Because of his belief in the world spirit manifesting through collective humanity, Hegel had a strong appreciation — almost worship — of the state. He saw the state as the realization of the world spirit in a particular historical moment. Everyone is born into a historical context as part of a state, and participation in the state is, for Hegel, participation in history and in the evolution of the world spirit.

1788 CE Arthur Schopenhauer
Summary:
For most of his life, Schopenhauer was almost completely disregarded. He only gained recognition later, primarily for his masterpiece The World as Will and Representation. All his later writings were aimed at expanding and deepening this central work.

Although his philosophy follows in the tradition of Kant and Western thought, Schopenhauer was also deeply familiar with Eastern traditions such as Hinduism and Buddhism, which heavily influenced him. He was also an impressive system-builder in his own right.

Schopenhauer sought to understand the world he lived in by identifying its underlying reality. Starting from Kant’s epistemology, he agreed that we only perceive the world as phenomena — shaped by the human mind — and that the noumenon (or das Ding an sich, the “thing-in-itself”) lies beyond our direct experience.

While Kant claimed we could never know the thing-in-itself, Schopenhauer tried to find clues to it through introspection and analysis of experience. He argued that for anything to be different from something else, it must differ in time or space — both of which are forms of human perception, not part of the world-in-itself. Therefore, the noumenal world must be fundamentally one, lacking multiplicity or separateness.

This view echoes certain ideas in Hinduism and Buddhism — not because Schopenhauer borrowed directly from them, but because he reasoned toward similar conclusions through Kantian philosophy.

He believed that while we perceive ourselves externally as physical objects, we also have immediate, non-sensory access to ourselves from the inside — through our inner life. This introspective awareness, however, is still limited; much of our behavior is unconscious, and our self-perception is filtered through time and subjectivity. Thus, even this doesn’t give us full access to the thing-in-itself.

So how did Schopenhauer attempt to grasp the noumenal world?

By analyzing our internal experience, he concluded that its core is not thought, reason, or matter — but will. This “will” is not a personal or conscious force, but a blind, aimless striving — an impersonal, energetic principle. One could also think of it as analogous to “energy,” long before Einstein’s equation (E=mc²) described matter and energy as interchangeable.

Based on this view, Schopenhauer saw the world as a horrifying place — full of suffering, disease, death, and relentless struggle. If the world of appearances reflects the nature of the underlying reality, then the noumenal world must be deeply troubling. That’s why Schopenhauer is often called one of the great philosophical pessimists.

Still, he believed there were temporary ways to escape suffering. One was through aesthetic experience — art. Normally, when we see something (e.g., food), we immediately desire it. But when we view a painting, we engage with it in a detached, contemplative way. Art, then, allows us to step outside our will-driven existence and glimpse something deeper.

Because Schopenhauer believed that all reality is one, he also thought that all humans are fundamentally one. Therefore, compassion and empathy are the basis of morality. To harm another is to harm oneself. This sense of unity in suffering forms the foundation of ethical behavior.

Ultimately, since reality is driven by a blind and painful will, Schopenhauer believed the best path was to deny the will — to detach from worldly desires and reject striving altogether. This final step in his philosophy mirrors certain Buddhist ideas about renunciation.

The philosophers most influenced by Schopenhauer include Nietzsche, Freud, and Wittgenstein.

Modern Age

The Modern Age, spanning roughly from 1800 to 1950.

1813 CE Søren Kierkegaard
Media: Angels Egg 1985
Summary:
A Christian existential philosopher and partly Romantic. Kierkegaard was less concerned with this world, as most Romantics were, and more focused on the next world — the world of God. Passion, for him, was not for its own sake, but for God and faith. He responded to the Enlightenment’s failure to reconcile faith and reason by choosing faith. A strong critic of European culture, particularly what he called “Sunday Christianity,” Kierkegaard believed that true Christianity cannot be turned on and off; its message is so powerful that it must permeate one’s whole life. Faith for him was like water and fire with reason — incompatible. He didn’t consider objective truth or reason to be very important. Instead, he focused on the truth of how one should live. For Kierkegaard, living well was the most important thing.

A critic of Hegel, Kierkegaard was deeply individualistic, in contrast to Hegel’s emphasis on the communal. He thought Hegel stole away human agency, making people mere products of history. For him, the individual’s existence and life were central, and philosophy should not dwell on metaphysical speculations. Our time on earth is short, and we should focus on living well and finding subjective truths.

Since humans can never fully comprehend God’s truth, we must believe. He emphasized that it does not matter if Christianity is objectively true; what matters is whether it is true for the individual.

He divided life into three stages:

• Aesthetic: Living for pleasure and momentary joys (common in Romanticism).
• Ethical: Living according to virtue.
• Religious: Following Christian tradition and making a leap of faith.

Kierkegaard believed that one must choose between a life of religious faith or secular skepticism and reason — they cannot mix, and there is no objective standard for making this choice. This existential decision shapes the rest of one’s life.

1818 CE Karl Marx
Summary:
Marx’s starting point was Hegel, but he diverged from Hegel’s idealism into a more practical, political philosophy. He can be described as a historical materialist, arguing that the material conditions of life shape human reasoning. Marx agreed with Hegel’s dialectical method, but instead of the spiritual development of society (as Hegel thought), he argued that the material conditions — the basis of society — determine its spiritual and intellectual life — the superstructure. The basis consists of the economic forces, particularly the ownership of production, which determines the political and ideological structure of society.

Marx believed the ruling class, who controls the means of production, also controls the moral framework of society. There is no eternal natural law, and all of history is a history of class struggle, where those who control the means of production dominate society. Marx’s theory of capitalism predicted that the system would eventually collapse. As capitalists reinvest in production, creating more efficient factories, fewer workers would be needed, leading to a classless society where everyone owns the means of production, thus resulting in communism.

1844 CE Friedrich Nietzsche
Summary:
Existentialist thinkers differ greatly: when Kierkegaard asks the question of faith versus reason and chooses faith, Nietzsche chooses reason. Nietzsche is amoral; for him, morality is an impediment to the superior man. Instead, Nietzsche focuses on power. He wants to replace religion with art. One can compare Nietzsche to a seismograph—he could sense the beginnings of an intellectual earthquake that would later disrupt academia greatly. He did not create this earthquake, but he was able to foresee the implications of Western thought and the crisis the West entered after Darwin.

This earthquake Nietzsche detects can be encapsulated in the sentence: “God is dead, God remains dead, and we have killed him.” Nietzsche did not kill God; rather, the development of Western culture and science—shifting from a mysterious, mythological interpretation of the world to a more sophisticated, naturalistic, and scientific outlook—did.

Nietzsche is warning of the end of theology, metaphysics, morality, and the tradition of Western philosophy. The goal of his works is to undermine theology, God, and metaphysics, and to bring people fully into this world, destroying the illusions they have lived in. Just like Kierkegaard, he is very radical: he believes one must go the full way with all of one’s being.

Nietzsche thinks thinkers like Socrates and Jesus have led the West astray by pointing people toward another realm—the realm of forms and heaven. But, he insists, there is only one world. We should love this world, find the beauty in it, and perfect it, instead of looking toward another world. As such, we should reject all metaphysics. In other words, he aims at a reevaluation of all morals and values. With that, Nietzsche sees himself as the destroyer of all theology and the tradition of Western philosophy, since philosophy needs metaphysics, and he believes he has exposed its foundations as hollow. He thinks philosophy ends with him.

Just as Socrates uses irony as a literal trick, so Nietzsche uses oxymorons. But unlike Socrates, Nietzsche is often much more obscure, rarely committing himself to any clear logical position, instead using his writing to perplex people and stimulate thinking. It reminds me of the Buddhist practice of koans: short phrases meant to perplex and shake the student, thus leading to enlightenment. Nietzsche is therefore more of a poet-philosopher, like Plato, than a systematic thinker like Aristotle.

For Nietzsche, what makes man great is the ability to give up herd morality. All our moral values have been created to suppress the superior man. “I don’t care about the masses of human beings; the only people worth something are the superior people,” he suggests. Humans are simply animals that emerged from evolution, yet somehow got it into their heads that they are special and that the world revolves around them. But even if that is false, we humans must still do something. Here Nietzsche says the natural motive of all living things, including humans, is the “will to power.” The reason why organisms reproduce, compete, and conquer is because all organic life is driven by the will to power. For example: a king conquering territory is an expression of the will to power; a scientist making a discovery is an expression of the will to power; even a saint fasting and sacrificing himself is the saint’s will to power. And if there is no God and thus no salvation, then the only serious, worthwhile thing left is art—an attempt at worldly salvation.

1870 CE John Stuart Mill
Summary:
Most widely known for developing the theory of Utilitarianism, the belief that what is moral is what maximizes happiness and minimizes suffering. In his work On Liberty, he argued that society should allow individuals the maximum possible freedom unless their actions harm others.

1889 CE Martin Heidegger
Media: My Dinner with Andre
Summary:
Although Heidegger himself was not an existentialist, existentialism can be seen as a child of his philosophy. He borrowed concepts from Kierkegaard but reformulated them in a unique way. Heidegger’s greatest work, Being and Time, focuses on the fundamental question: what does “being” mean? Instead of looking outward at the external world, he approached the problem by turning inward, focusing on human experience.

In everyday life, we understand being in relation to objects — for example, “the grass is green” or “the sun is a star” — but we lack an understanding of being itself in a general, fundamental sense. Heidegger wanted a definition of being that wasn’t abstract and disconnected from life but was rooted in everyday experience. To achieve this, he introduced his concept of Dasein — a term for human existence — arguing that only by examining Dasein could we truly understand being.

Dasein experiences the world through three interrelated structures: understanding, mood, and discourse.

• Understanding refers to our ability to interpret and give meaning to the world around us.
• Mood represents our emotional state, shaping how the world appears to us — for example, experiencing things differently when we are joyful or sorrowful.
• Discourse refers to language, which is essential for expressing and interpreting experience; things can only truly be understood when they are articulated in language and shaped by our mood.

One of Heidegger’s major ideas is that freedom must be earned. It emerges as a response to the confrontation with human existence itself. Our true reality lies in Being, not in the distractions of everyday trivialities. If one lives constantly in distraction, one forfeits the chance to be genuinely human. Heidegger warned against becoming a “mass-man,” someone who merely follows the herd, avoiding authentic engagement with reality. His imperative is to strive for authenticity — to become a true individual through deep inner cultivation and confrontation with existence.

A crucial part of confronting reality is facing our own mortality. Heidegger emphasizes the immediate, personal realization that we will die. Time — as the horizon of all possibilities — is central to human existence.
This realization leads to a deep anxiety:

• We project ourselves into the future and recognize death as the end of all possibilities.
• We look into the past and realize what we could have been but failed to achieve.
• We see ourselves in the present as incomplete and not fully understanding Being.

This creates a sense of guilt: a debt to ourselves that can never fully be repaid. This tension — between our unrealized possibilities and the certainty of death — defines the human condition. Thus, Heidegger suggests: it is not what you do that matters most, but how you do it — with authenticity, facing Being and mortality honestly, rather than evading them.

1905 CE Jean-Paul Sartre
Media: Synecdoche, New York
Summary:
A French existentialist philosopher, Jean-Paul Sartre centered much of his work around a fundamental question: why is it that even when we are housed, fed, and comfortable, we still manage to feel dissatisfied with life?

Sartre argues that inanimate objects are complete — they simply exist. They have no need for progress or aspiration; they are what they are. However, humans are different: we are beings-for-itself. We can not only think about what is but also about what could be, what might be, and what ought to be. As conscious agents, we can make decisions. Sartre calls this ability to imagine and move toward possibilities — things that are not yet — nothingness.

From this insight, Sartre concludes that nothing internal prevents us from making any decision, no matter how destructive it might be. In other words:

“We are condemned to be free.”

With this radical freedom comes radical responsibility for our actions — and an anxiety over the destructive possibilities our freedom opens up. Sartre calls this feeling the anguish of the future. But there is also an anguish of the past: the regret of missed potentials, the sorrow of not having lived up to our own standards, of having broken our own promises. At any point, we can betray our commitments — nothing is forcing us to be consistent. Even following rules requires active reaffirmation at every moment, and this perpetual freedom itself is a source of anxiety.

If there were a God, Sartre says, we would have a predetermined place in the world, and we would not experience this crushing freedom. But since there is no God, we alone must decide what is right, how to act, and what to value. We cannot hide behind anyone or anything.

Sartre further argues that most people do not deeply feel this anxiety. They live their lives in bad faith, ignoring the reality of their radical freedom. They live more like things — fixed objects — rather than conscious beings. For instance, a waiter who completely identifies with his role, saying “I am a waiter” and nothing more, is living in bad faith. But bad faith is not limited to professional roles; even casual phrases like “That’s just who I am” express the same illusion — the idea that there is a fixed, static self. For Sartre, the desire to be a fixed object is ultimately the desire to be dead.

Other people also play a huge role in Sartre’s philosophy. Our personhood is closely linked with others: it is through others that we become self-conscious in certain ways. Sartre describes a common experience: you are going through your routine in public when you suddenly feel that you are being watched. Instantly, your behavior changes — you shift from being a subject acting freely to becoming an object in someone else’s eyes. Sartre calls this phenomenon the look (see ‘I see them Watching’).

So what can we do? How can we make ourselves “complete”?

Sartre’s answer: we must live authentically, both individually and in relation to others. We create who we are and what we value through action. Who we are is made, not found. To live authentically is to craft our own values, to choose our path, and to walk it with full awareness of the freedom and anguish that come with it. We must embrace the truth that we are totally free — the authors of our own lives.

1913 CE Albert Camus
Media: Taste of Cherry, Sunset Limited
Summary:
A French existentialist, Camus is nowadays most famous for his phrase: “One must imagine Sisyphus happy.”

Unlike earlier existentialists, Camus begins his worldview with the assumption that life is meaningless and uncaring, and instead focuses on how to deal with it. Existential philosophers before him, such as Kierkegaard, often tacitly assumed that life had inherent meaning, and that an existential crisis was merely the temporary loss or forgetting of that meaning. In other words, they were concerned with rediscovering life’s objective, transcendent value.

But Camus rejected this approach. For him, trying to imbue life with a false, transcendent meaning was a betrayal of reason — it was choosing comforting illusions over facing the truth of nihilism.

Central to Camus’ thought is the concept of the absurd: the tension between the apparent meaninglessness of life and the human need for meaning. This tension is most deeply felt during an existential crisis, which he calls a “sudden awareness of the absurd” — the realization that life is dishonest, like a stage play pretending to have a deeper plot.

Many people, when confronted with this realization, do as Kierkegaard suggests and make a “leap of faith” toward some higher meaning. But Camus wanted to explore a life without hope and without appeal. He famously wrote:

“One of the only coherent philosophical positions is thus revolt. It is a constant confrontation between man and his own obscurity. […] It challenges the world anew every second. Just as danger provided man the unique opportunity of seizing awareness, so metaphysical revolt extends awareness to the whole of experience. […] It is not aspiration, for it is devoid of hope. That revolt is the certainty of a crushing fate, without the resignation that ought to accompany it.”

For Camus, it is not enough to simply realize life’s meaninglessness; one must also fully acknowledge the conflict between the human desire for meaning and the world’s indifference. We must live our entire lives in full knowledge of the absurd. This, for Camus, is the only consistent philosophical position.

This revolt or rebellion means doing things with the full knowledge that they are ultimately pointless — doing them precisely because they are pointless, as an act of defiance. This battle against the absurd can best be fought not alone, but together with others. Through solidarity with our fellow humans — who are fighting the same battle against the absurd — we can embrace a universal revolt, one that unites all of humanity in a shared, courageous defiance.

Contemporary

As defined, starting after the end of World War 2 or after the end of time of the major existentialist.

1919 CE G. E. M. Anscombe
Articles: The Meaning of Ought
Summary:
Student of Wittgenstein, she was best known for her influential paper ‘Modern Moral Philosophy,’ in which she criticized modern moral theories like utilitarianism and Kantianism, and advocated for a return to virtue ethics. She was also known for her work ‘Intention,’ which laid the foundation for modern philosophy of action.

1921 CE John Rawls
Summary:
Famous for his theory of justice, Rawls argued that a just society would be one where individuals could determine the structure of society and its laws, but with the trick that, once the rules are set, individuals would not know their position in society (e.g., whether they would be male or female, rich or poor, a worker or a capital owner). This “veil of ignorance” would produce a just society, as people would design a system that protects the most vulnerable because they wouldn’t know if they would be among them.

Less Relevant Philosopher

1646 CE Gottfried Wilhelm Leibniz
Summary:
Gottfried Wilhelm Leibniz tackled the problem of evil by famously arguing that our world is “the best of all possible worlds.” He believed that, although suffering and imperfection exist, they are part of a greater harmonious whole that only a divine, omniscient being (God) could have conceived — a world that balances all possible goods and evils better than any alternative.

Leibniz also formulated the principle of the identity of indiscernibles, which states that if two entities share all the same properties, then they are not two entities but one and the same. There can be no true duplicates in reality.

In his metaphysical work “Monadology,” Leibniz introduced the idea that the universe is composed of an infinite number of simple, indivisible substances called monads. These monads:

• Have no parts (they are simple, like atoms, but not material),
• Do not exist in space or time i.e. are not part of material world,
• Do not interact with one another directly,
• Are entirely defined by their internal qualities or perceptions,
• Are all unique — no two monads are the same.

Instead of interacting, monads follow a “pre-established harmony” — a kind of divine programming instilled by God. Each monad unfolds its internal program perfectly in sync with every other monad, creating the illusion of causation and interaction in the world. This model allowed Leibniz to preserve both scientific determinism and theological order, while avoiding materialism.

1806 CE Max Stirner
Media: Rope
Summary:
Max Stirner is a German philosopher. His central thesis—and what he is most famous for—comes from his work The Ego and Its Own, where he presents the concept of egoism: “each human being should only care about themselves.”

Stirner outlines a three-stage progression in the development of human values, which he believes culminates in egoism. The first stage he calls “realism.” This refers to individuals concerned with real-world objects and the fulfillment of their own appetites—essentially the mindset of young children. He believes ancient Greece exemplified this stage, as people there were focused on using their minds to influence the world. A prime example, he claims, are the Sophists, with Socrates being the exception. This could be challenged, for instance, by pointing out that Stoics in ancient Greece were more concerned with universal values than with the material world. The main characteristic of the realist is that their will is unfettered by internal principles but constrained by the external world and undisciplined desires.

The next stage in Stirner’s development is “idealism.” By this, he means being ruled by ideas—or “spooks,” as he calls them. In this stage, we become guided by abstract principles like justice and morality. Stirner associates this phase with adolescence or young adulthood, when individuals often dedicate their lives to causes they perceive as greater than themselves. Christianity is a prime example of this stage: it is not concerned with living life to the fullest but with principles that claim intrinsic value. Christ did not say, “Pick up your things and follow me” because they were useful, but because they had supposed intrinsic worth. The key characteristic of the idealist is loyalty to their ideas. They have conquered desire but are in submission to internalized principles. The ultimate idealist is someone willing to die for an idea—something we often admire, but Stirner sees as foolish.

Finally, we arrive at the stage of “egoism.” The egoist asserts total authority over their own person and actions. Egoists are not ruled by desires, the external world, or abstract ideas. They reject the authority of political or religious systems and act only in their own self-interest. Stirner associates this with the philosophy of full-grown adulthood. Importantly, Stirner does not think people should avoid acting on ideas or holding values. Rather, we should not regard those ideas as more important than ourselves. He asks: what was the point of Socrates’ moral stand, given that once he died, he was no longer around to see the fruits of his values?

Because of this view, Stirner was not a fan of democracy. He believed that under feudalism and monarchy, the state’s actions reflected the will of an individual. In democracy, however, the state’s authority stems from “the people,” which he considered just another “spook”—a fictional abstraction that reduces real, existing individuals to an idea. Stirner further argues that if the state protects our property instead of us doing so ourselves, then we don’t truly own that property. It is merely loaned to us by the entity securing it. Even our personal agency is loaned, since the state can pass laws restricting our behavior. If our actions can be revoked at any time, then our autonomy is not truly ours.

“Whoever knows how to take, to defend, the thing—to him belongs property.”

Thus, Stirner believes revolutionary and political movements are too focused on what gives people rights—like Marxists who ask who ought to own the factory. For Stirner, that misses the point. The output of the factory belongs to whoever can take it. He argues the entire concept of rights should be dissolved.

Stirner’s imperative is to embrace egoism and act solely in our own best interest. This can be interpreted in two ways:

1. A moderate reading, where egoism means accepting responsibility for our own decisions. When we make a choice, we shouldn’t appeal to a transcendent value but acknowledge it as our own, chosen value—similar to Sartre’s existentialism. The focus is not on the principle itself, but on the choice to follow it.
2. A radical interpretation, where egoism becomes pure self-interest. The goal is to extract everything possible from life, regardless of the consequences for others—essentially radical selfishness.

Finally, it must be said that Stirner’s philosophy struggles with the concept of destructive desires, which we now recognize as a real part of human psychology. He either suggests that we should not act on such desires—thereby reintroducing a form of idealism—or he implies that we should act on them, which reduces his egoism (the idea of doing what is best for ourselves) to simply doing whatever we want.

References:

• Book: Sophies World
• Podcast: Philosophize This!
• Professor: Michaeal Sugrue
• Lecture at the KIT: “Introduction to Philosophy”
• YouTube: UnsolicitedAdvice
• TV: The Great Philosophers

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