On Why I Loathe Existentialism

The Sartrean school loves to talk about human freedom and the moral responsibility that accompanies it: "Man can do what he wants, therefore he is free, and therefore he must be responsible for his actions." This is treated as some sort of self-evident truth, but it is precisely this premise that is untenable. Here is why:

1. For a person to bear responsibility for their actions, they must both need to and be able to take responsibility for their own nature (personality), because their actions are the direct result of their nature.
2. However, one cannot be held responsible for their own nature because nothing in this world can generate itself; nothing is causa sui (self-caused).

A person's nature is jointly shaped by genetics, heredity, external environment, and other factors over which they have absolutely no say. They did not freely choose their nature when they logged into this game of "Earth Online"; rather, they were assigned a nature by the game's system. This nature drives them to do what they desire, yet they cannot master their own desires. That a person can do what they want merely means their body is not physically restrained—it only signifies physical freedom. The question we ought to ask is: Is this person's nature free? Do they possess freedom in a moral sense, rather than merely a physical one?

The answer is no. Although individuals harbor a subjective illusion that their actions are self-authored and therefore free, they are merely experiencers of this world. Like anything else in the universe, a person's nature is simply an object of their consciousness and is thus subject to strict necessity (determinism).

Furthermore, if the world were not governed by strict necessity, it would be a living nightmare. It would mean humans could act with complete randomness—even a saint might attack you for no reason at all. If human free will existed in an absolute sense, moral responsibility would precisely thereby become impossible.

Moral responsibility is nothing more than a product of human social construction. Without human civilization, there would be no morality, only the law of the jungle found in the animal kingdom. Morality is not sacred; it is simply a set of rules that individuals must follow in order to live within human society. The Golden Rule—"Do not do unto others what you would not have them do unto you"—adequately summarizes morality in the eyes of the vast majority. As for those capable of unconditional, pure altruism and compassion, they are merely a rare exception. Without laws, people would very quickly understand the meaning of homo homini lupus (man is a wolf to man). Therefore, it is not that morality birthed law, but rather that law birthed morality.

Figures like the ancient Chinese strategist Guiguzi tore away the mask of morality long ago, exposing the baseline of human nature. He mapped out human relationships in what is essentially a four-quadrant matrix based on desire and circumstance:

• When people share the same circumstances and grow close, it is because cooperation yields mutual benefit and a win-win outcome.
• When people share the same desires but remain distant and defensive, it is because their interests are mutually exclusive, destining them to a zero-sum game.
• When people share the same aversions (threats) and huddle together, it is out of a "lips and teeth" interdependence; if one falls, all fall.
• When people face the same crisis but distance themselves and shift blame, it is because as long as disaster can be redirected, one party can save themselves at the other's expense.

This matrix illustrates that whether people become allies or enemies is determined solely by human desire and external circumstances. There are no eternal allies and no eternal enemies. As Guiguzi further stated:

"There are no permanently elite individuals, and no fixed rules for handling affairs. The sage has no permanent allies, nor anyone he absolutely cannot ally with; he has no counsel he blindly listens to, nor any he absolutely refuses to hear. As long as it brings success to the endeavor and aligns with the strategic calculus, he will engage with it and make it his guiding principle."

If my loathing for Sartrean existentialism stems from a distaste for its pedantic moralizing, then my loathing for Camus’s absurdism stems from how his Sisyphean rebellion—against a cold, unfeeling universe that couldn't care less whether you rebel or despair—feels entirely like an exercise in self-indulgent ego-stroking. (I categorize Camus’s absurdism here as a broad subset of existentialism, despite his own adamant efforts to distance himself from the label).

Furthermore, Camus sidestepped the real issue: In a godless world, where death means absolute annihilation and the erasure of all life's meaning, why exactly should humans keep living?

Camus pulled a bait-and-switch. Right out of the gate, he declared: "There is but one truly serious philosophical problem, and that is suicide." But I can't help but ask him: Who told you that someone confronting the meaninglessness of the universe would inevitably commit suicide? Who told you that asking "Why live?" (i.e., inquiring about the meaning of life) is synonymous with asking "What reason is there not to die?"

Inquiring about the meaning of life merely indicates that a person has fallen into a state of bewilderment. This question can be purely philosophical, not psychiatric. Yet Camus, striking a self-serious posture, displayed a kind of pity that is entirely inappropriate to direct at a nihilist.

If his The Myth of Sisyphus is to be viewed as a response to existential nihilism, it can only be seen as a clumsy, evasive, and self-congratulatory one.

My dissatisfaction with Heideggerian existentialism stems from the fact that he evades all the aforementioned problems and downgrades them to issues unworthy of discussion. What I dislike most is his repeated insistence that his concept of "Being-towards-death" (Sein-zum-Tode) is not a normative ethical standard, but purely an ontological speculation. What does that even mean? It means he fashioned himself as having diagnosed the fundamental flaw in millennia of Western philosophy, yet he shrank back at the exact moment he should have proposed an ethics. It is a duplicitous, hypocritical stance.

As for Nietzschean existentialism, my assessment of it can be summed up in four words: Putting on a brave face.

When Nietzsche realized the terrifying possibility revealed by Schopenhauer—that "Truth" does not equal "Good"—his reaction was not to hold back his tears and accept this dark reality, but rather to try and flip the entire table. In a manner that may have seemed subversive at the time, but today looks incredibly pretentious (with its underlying motives all too transparent), he attempted to prove that objective truth simply does not exist, thereby dodging the problem entirely. Accompanying this denial of objective truth was his insistence that one must "affirm the value of life no matter what"—a rhetoric that reads as though he were simply triggered by Schopenhauer.

Finally, there is Irvin Yalom. Though strictly speaking he is not a philosopher, I cannot bypass his Existential Psychotherapy here, because all my grievances with existentialism can essentially be encapsulated in my critique of this book's themes.

Yalom first defines the four "ultimate concerns" of life:

1. Death
2. Isolation (referring to existential isolation, meaning everyone is trapped in their own physical shell and can never truly merge minds with another)
3. Freedom (a seemingly infinite freedom accompanied by endless bewilderment and the heavy burden of responsibility)
4. Meaninglessness

It is regrettable that a book with such profound themes ultimately drifts into a quasi-cynical attitude—essentially advising readers not to overthink, not to ask "why," and to just focus on opening themselves up to the world and building connections with others.

But in reality, only Death and Meaninglessness truly matter here, and perhaps only Death actually constitutes a problem. Compared to death, meaninglessness is nothing more than the shattering of symbolic immortality. People do not suffer because the universe lacks meaning; they suffer because they realize that the universe's meaninglessness dictates that, no matter how hard they strive, they will leave nothing behind to be remembered by others after they die. It is the subsequent realization of their own transience and mortality as animal beings that causes them agony.

There is only one true philosophical problem, and that is learning how to face death—in an absolutely atheistic sense, of course.

"At that time, Prince Bala went to the assembly of the Six Heretical Teachers and asked Purana Kassapa: 'What is the doctrine you revere? What do you teach your disciples? What fruit is obtained by diligently practicing the holy life?'

The teacher replied: 'O Prince! The doctrine I hold, and the view I proclaim is this:
There is no giving of alms, no receiving of them, and no sacrifices. There are no good or evil deeds, no karma, and no karmic retribution. There is no this world, and no next world. There is no father, no mother, and no beings born through transformation. There are no Arhats in this world... All these things do not exist.

What possesses life is merely labeled as being "alive." When this body expires, the great elements separate, and there is no further continuation of life—this is called "death." Earth returns to earth, water returns to water, fire to fire, wind to wind, and the senses dissolve into the void. Four men carry the corpse to the cremation ground and burn it with fire; nothing remains but bones, entirely devoid of consciousness. In this, the fool and the wise suffer the exact same fate. Therefore, giving is an illusion, receiving is an illusion, and those who claim these things exist speak only falsehoods.'" (Mūlasarvāstivāda Vinaya)

There is only one truly serious philosophical problem, and that is death. To confront the biological inevitability of one's own mortality, yet still choose to live, is to answer philosophy's ultimate question through action.

Once this truth is understood, the vast majority of life's daily anxieties naturally pale in significance. In psychology, Terror Management Theory (TMT) attempts to prove—or perhaps has already proven—that the ultimate driving force behind all instinctual human behavior is the desperate attempt to evade the biological reality of our inevitable death.

Religion attracts followers by promising literal immortality. Conversely, nations, cultures, and societies encourage individuals to build worldly legacies and contribute to grand narratives, thereby offering a form of symbolic immortality: though you will die, your name will be remembered. The Norwegian philosopher Peter Wessel Zapffe taught a similar doctrine. When these theories are integrated and complement one another, the framework looks like this:

The most common coping mechanisms are "denial" and "isolation"—outright denying one's mortality, or denying that death is the absolute end, thereby banishing all thoughts of death from conscious awareness. Because this defense mechanism operates closest to the center of conscious awareness when triggered, it is known in psychology as a proximal defense.

The next strategy is "distraction"—amusing ourselves to death. We indulge in hedonism, scroll endlessly through short videos, and stuff our lives full of trivialities. This perfectly aligns with what Martin Heidegger described as the "fallen" (inauthentic) state of everyday human existence.

Finally, there is "anchoring" and "heroism"—dedicating oneself to collectives such as the state, a culture, a corporation, or a religion, in a desperate bid to find an anchor amidst the chaos of consciousness. We rely on these anchors to endow our lives with meaning, order, and the hope of continuity. If the anchor shatters, the individual collapses, and raw death anxiety is awakened. Therefore, people will defend their anchors at all costs—fanatical nationalism being a prime example. Because this operates furthest from immediate conscious awareness, it is termed a distal defense. While people are aware of what they are doing, they rarely understand why they are doing it, assuming their actions are simply natural or self-evident. But this is an illusion; there is a profound psychological cause behind all human behavior.

When an individual feels they are meeting the standards of their internalized cultural worldview, and thus believe they are worthy of the literal or symbolic transcendence of death that this worldview provides, they acquire self-esteem. Self-esteem and anchoring are two sides of the same coin, collectively known as the cultural anxiety buffer.

Viewed from this perspective, those who walk the path of "Being-towards-death" are acting in direct defiance of their biological instincts—which is tantamount to rebelling against the very order of nature.

It is a secular, non-religious form of spiritual discipline, one that is destined to be solitary and arduous. Yet, whoever truly comprehends it grasps the key to unlocking an entirely new way of living.

Prologue Hello everyone! I am from China, and I originally wrote this essay in Chinese to help readers without a philosophical background understand this foundational text. To share it with the r/Schopenhauer community, I used an advanced AI language model to carefully translate and adapt it into English. I have previously posted a similar essay in this subreddit, and I hope you find this breakdown just as helpful and thought-provoking!

Arthur Schopenhauer (1788–1860) was a German philosopher who is primarily remembered in the history of philosophy for his pessimism. While his undisputed masterpiece is The World as Will and Representation, his earlier philosophical book, On the Fourfold Root of the Principle of Sufficient Reason, lays the critical foundation for his entire system.

The purpose of this essay is to make the core essence of this foundational text accessible to readers without a philosophical background. To achieve this, the essay is divided into two parts. The first part introduces the prerequisite knowledge necessary to understand the book, including some brief fragments of philosophical history. The second part directly introduces the book's core arguments, providing a thorough explanation of each.

First, let us look at the definition of the Principle of Sufficient Reason:

"The Principle of Sufficient Reason is a powerful and controversial philosophical principle stipulating that everything must have a reason, cause, or ground. This simple demand for thoroughgoing intelligibility yields some of the boldest and most challenging theses in the history of philosophy." — Stanford Encyclopedia of Philosophy

Schopenhauer’s own definition of the principle goes like this: "Everything that is, is only in so far as it is through another." (On the Fourfold Root, §47)

Let's break down the meaning of the book's title to make it clearer:

● On (A treatise concerning)

● the Fourfold (Four different forms or manifestations of)

● Root (The foundation or basis)

● of the Principle of Sufficient Reason.

Put together, it means: An argument clarifying the four distinct ways the foundation of the Principle of Sufficient Reason manifests.

It is crucial to note that there are not four separate principles. There is only one Principle of Sufficient Reason, but when applied to four different types of objects, it reveals four distinct faces (or forms).

When Schopenhauer was 64 years old, he wrote in a letter: "For my entire exposition is merely the completion of Kantian transcendental idealism." (Denn meine ganze Darstellung ist bloß die Vollendung des Kantischen transscendentalen Idealismus.)

Therefore, understanding Kant's transcendental idealism is an absolute prerequisite for understanding Schopenhauer's philosophy.

But first, we need to know what epistemology is.

Epistemology is the branch of philosophy that studies the nature, origin, and limits of human knowledge. The "transcendental idealism" pioneered by Kant is a specific kind of epistemology. Compared to general epistemology, it asks much deeper questions: What can we know? What can we not know? How are pure mathematics and geometry even possible? What is the true nature of things that exist prior to experience and are considered universal laws (like the law of causality)?

All of these questions actually hint at Kant's ultimate answer: If something exists in the world, yet is not inherently part of the world as an object in itself, then it can only be something that the subject (the human mind) imposes onto the world.

Next, let's look at Kant himself. To do so, we must outline the primary philosophical problems of Kant's era.

Before Kant, Western philosophers were methodologically trapped in two extreme, opposing camps, both of which had gone off the rails.

One camp was Empiricism. They believed all knowledge must be rooted in experience; without experience, conclusions drawn from pure rational speculation could be completely detached from reality. When this line of thinking was pushed to its extreme by David Hume, he despairingly discovered that we have no way to prove through experience that "causality" actually exists. If the sun shines on a stone and the stone becomes hot, the entire event already presupposes the law of causality, so you cannot derive a proof of causality from the event itself. No empirical event can do this. Because Hume did not believe in "complex ideas that cannot be proven by experience yet are necessarily true," he concluded that causality is merely a psychological illusion. We preserve this illusion out of habit simply because it makes understanding the world convenient.

The other extreme was Rationalism. Philosophers in this camp believed we didn't need to worry about experience at all; human reason and the universe share the same underlying structure, so we can discover universal truths simply by sitting and thinking. A key representative of this school was Leibniz, the first to systematically formulate the Principle of Sufficient Reason. However, as a "philosopher" devoted to God, he summarized the approaches of earlier theologians and cleverly tried to use this principle to "prove" God's existence. The argument went like this: The world must have a cause, and that cause cannot be the result of yet another cause (otherwise, we fall into an infinite regress). Therefore, there must be a "first cause," and that is God. Furthermore, since God is supremely good, this world must be the best of all possible worlds.

This philosophical farce continued until Kant arrived on the scene...

Kant was originally a university lecturer who taught science for many years and adhered to Leibniz's philosophy. Because of this, when he read Hume's doctrines, he was violently awakened from his "dogmatic slumber." He was deeply dissatisfied by the almost total silence of his contemporaries regarding Hume's challenge. Kant believed that if Hume was left unanswered, the very foundation of science—causality—would be completely destroyed. Kant spent over a decade thinking and finally wrote The Critique of Pure Reason.

One of the book's goals was to critique the arrogance of human reason by drawing a strict boundary where it could effectively operate. Inside the boundary, everything is fine; outside the boundary, propositions detached from experience—such as "Does God exist?", "What is the essence of the universe?", or "How did the world begin?"—are pure nonsense. Another goal was to provide a philosophical foundation for the most advanced science of the time: Newtonian physics.

Kant's response was revolutionary. He argued that things like time, space, and the law of causality are not inherent properties of the universe itself, but rather the way human beings view the world—they are the default "factory settings" of our cognitive system. However, these factory settings are so fundamental that, even though the world as we experience it is largely the result of human mental processing, its reality is objective and independent of our personal will.

Kant's argument regarding time and space is very straightforward: We can imagine a period of time where nothing happens, but we cannot imagine the absence of time. We can imagine a space entirely empty of objects, but we cannot imagine the absence of space. For anything to be perceived by us, it must exist within space and time. Imagine the world is a movie; we used to think space and time were the sets and props inside the movie. Kant pointed out that space and time are not the contents of the movie at all—they are the screen on which the movie is projected, the fundamental prerequisite that makes viewing possible.

Kant offered another argument: Mathematics and traditional Euclidean geometry are necessarily true in any universe. We cannot even conceive of the contrary (e.g., "1+1 ≠ 2" or "the interior angles of a triangle do not equal 180°"). How is this possible? It can only be understood this way: counting is essentially derived from our innate concept of time, and geometry is derived from our innate concept of space. Therefore, concepts built upon the human mind's base code cannot be wrong, nor can we imagine them otherwise.

Kant called time and space the two a priori forms of sensibility (the capacity to sense), meaning they exist prior to all experience. Causality, on the other hand, was classified as one of the twelve innate cognitive structures (which Kant called categories) of the understanding.

Kant's a priori proof of causality is highly complex and counterintuitive, but it boils down to this:

Imagine a large house. Standing in front of it, you can look at the top half first, or the bottom half first. This subjective sequence of looking is arbitrary and reversible. Now imagine a boat floating downstream on a river. No matter how you look at it, your perception of the boat moving from upstream to downstream is mandatory and irreversible. In both examples, there is a temporal sequence to your perception. But how does your brain know the house is stationary while the boat is objectively moving? Kant explains that the state of the water and the boat upstream (cause) leads to the state of the boat downstream (effect). The causal relationship itself is irreversible. It is precisely because our brains are pre-equipped with the "glasses" of causality that we detect this irreversible compulsion and realize: "Oh! An objective event happened outside (the boat moved); it wasn't just my eyeballs darting around making me think the boat moved."

Schopenhauer thought Kant's explanation here was complete nonsense. Just because one event follows another in time absolutely does not mean there is a causal relationship between them, let alone prove that causality exists prior to experience. For example, night always follows day, and when playing a piece of music, the second note always follows the first. In both cases, there is a strictly mandated temporal sequence, but there is absolutely no "who caused who" causal relationship. Or, imagine someone walking down the street who gets hit by a falling object. Is there any causal relationship between "the person walking" and "the object falling"?

Schopenhauer provided his own a priori proof of causality: When light from the external world hits the human retina, it is merely a physiological stimulus (a blur of light). It is exactly because our brains are innately equipped with the cognitive mechanism of "causality" that our understanding immediately activates, recognizes this retinal sensation as an "effect," and projects outward to find the "cause" that produced the sensation. It is only at this step that we truly "see" external objects in our minds. In a sense, the objective world we see is already a manufactured product processed by the human mind via causality.

Schopenhauer's theory can be understood in a more grounded way: Imagine someone secretly pinches you. The sensation of pain happens entirely under your skin. If your brain did not have the pre-installed tool of "causality," you would simply feel an inexplicable pain and would never even think to ask, "What caused me to feel this pain?" This clearly contradicts reality. From this, Schopenhauer strictly distinguishes between "sensation" and "perception" (intuition): The five senses merely provide subjective sensations. The intellect acts like an artist, taking the raw materials handed over by its assistants (the senses) and using causality to craft our complete perception of the world.

Now we enter Schopenhauer's territory:

Here is a summary of the four different forms of the Principle of Sufficient Reason:

1. The Principle of Sufficient Reason of Becoming (German: Werden) — The law of physical causality. Its object is physical matter, and its corresponding subjective faculty is the understanding (Verstand).

2. The Principle of Sufficient Reason of Knowing (German: Erkennen) — The law of logical inference. Its object is abstract concepts, and its corresponding subjective faculty is reason (Vernunft).

3. The Principle of Sufficient Reason of Being (German: Sein) — The laws of mathematics and geometry. Its object is pure, a priori space and time, and its corresponding subjective faculty is pure sensibility.

4. The Principle of Sufficient Reason of Acting (German: Handeln) — The law of motivation. Its object is the will, and its corresponding subjective faculty is self-consciousness (inner sense).

Let's break down each of the four forms in detail:

1. The Principle of Sufficient Reason of Becoming

This applies to changes in physical reality. When we witness a change (e.g., the sun shines on a stone, and the stone becomes hot), we consciously or subconsciously seek the cause of this change. This is what we commonly call the law of causality. Schopenhauer placed a very precise limitation on causality: it only applies to changes, not to objects themselves, nor to the "universe as a whole." Here is why:

(1) There are two things in the physical world not governed by causality (they have no cause, no effect, and are neither created nor destroyed):

● Matter itself: Matter is eternal; only its form changes.

● Natural forces: Such as gravity and electromagnetism.

If matter itself and natural forces are indestructible and uncreatable, what exactly does the law of causality govern in the physical world? The answer: It only governs the "changes in states" when these forces manifest in matter.

(2) For something to be a "cause," it must itself be a change that just happened.

Consider this: If the cause of the stone getting hot is simply that "the sun exists" or "the stone exists" (assuming causality applied to objects themselves), then since the sun and the stone were both there yesterday, why didn't the stone get this hot yesterday?

The answer must be that a change occurred—for example, the clouds just parted, or the sun just rose to a specific angle.

Conclusion: Only when a state of equilibrium is broken and a change occurs can the next state (the effect) be triggered. If the cause were not a momentary change but something permanently sitting there, the effect would have happened long ago.

Since the law of causality only governs changes, this means every state that acts as an "effect" must have been caused by a change in a preceding state (the "cause"). The chain of causality stretches infinitely backward in time. To Schopenhauer, theologians who try to find an uncaused "First Cause" at the end of the chain are completely ignorant of, and are abusing, the law of causality. The chain of causality has no beginning.

2. The Principle of Sufficient Reason of Knowing

Consider the following examples:

1. We say John is a good student because he scored 100% on his test.

2. John scored 100% on his test because he studied incredibly hard.

In these statements, studying hard is the physical/historical cause of John scoring 100%. However, scoring 100% is the logical reason (ground of knowing) that allows us to conclude he is a good student. Confusing the two leads to circular logic, such as: "We judge him a good student because he studies hard" and "He studies hard because he is a good student." Therefore, a physical cause and a logical reason must never be confused.

Ordinary people often confuse the logical reason for a judgment with the physical cause of a phenomenon.

Schopenhauer accused theologians and philosophers who tried to prove God's existence through logic of sheer sophistry. When asked to explain the cause of God's existence (demanding empirical evidence for how God came to be), these individuals offer a reason of knowing instead. They argue: "Such empirical evidence is impossible because, by definition, God exists outside the world. He is the first cause, so nothing created Him. Furthermore, by definition, since God is the most perfect being, He must necessarily exist."

Schopenhauer's response to this trick was scathing:

"The proof is, in fact, already expressed in the concept itself, or at least exists complete within it, just as the chick exists complete in the egg that has been incubated for a long time... Thus, while all other things require a cause for their existence, the existence of God, brought to us by the cosmological proof, requires no such cause; the infinity existing in its concept is sufficient, or, as the proof itself expresses it: 'The concept of a supremely perfect being necessarily includes its existence.' This is the magician's clever sleight of hand... indeed a rather lovely joke... To such an ontological demonstration, the simple reply is: 'Everything depends on where you got that concept from: if it was drawn from experience, excellent, its object exists, and no further proof is needed; but if the concept was contrived from your own little empty head, then all its attributes won't help it; the concept is an absurd figment of the imagination.'" (On the Fourfold Root, §7)

Schopenhauer's radical separation of cause and reason has a profound purpose: to shatter human superstition regarding pure rationality. Since ancient times, humans have tended to believe, "As long as my logical reasoning is flawless, the conclusion must perfectly match reality." Schopenhauer completely rejected this. Unless a logical inference is not only formally valid but also based on premises grounded in empirical reality, it is merely a conceptual game. Even under ideal conditions, the order of thought (logic) can only be a reflection of the order of reality (physical causality). We must never detach from experience and dictate what the "truths of the universe" should be. To put it clearly: the order of thought must submit to the order of reality, not the other way around.

"The solution to the riddle of the world must come from an understanding of the world itself: the task of metaphysics is therefore not to fly above the experience in which the world exists, but to understand this experience fundamentally, for experience, whether inner or outer, is indeed the primary source of all knowledge." — Schopenhauer, Critique of the Kantian Philosophy

3. The Principle of Sufficient Reason of Being

In everyday English, we often use words like "being" and "existence" interchangeably to ask things like, "Do aliens exist?" or "Why does this object exist?" However, when we talk about the Principle of Sufficient Reason of Being, we are not talking about empirical "existence."

In the history of Western philosophy, "Being" (Sein) has a very specific meaning, typically contrasted with "Becoming" (Werden):

● Being (Sein): Refers to static, eternal, formally unchanging properties or relationships.

● Becoming (Werden): Refers to the dynamic process of transition from one state to another. (Because causality applies only to changes, Schopenhauer uses "Becoming" for the first root).

So, what is the Principle of Sufficient Reason of Being? Consider Schopenhauer's examples:

If you ask: Why are the three angles of an equilateral triangle equal? The answer is: Because its three sides are equal. But are the equal sides the cause of the equal angles? No, because we are not discussing a physical change or an effect that occurs over time. Is it merely a logical reason for knowing? No, because simply looking at the isolated concept of "equal sides" does not logically necessitate "equal angles" (the definition of equal sides doesn't explicitly mention angles). What we are dealing with here is a direct, structural connection within pure space.

Or, if you ask: Why is the past unchangeable and the future inevitable? This cannot be answered through logical analysis of concepts, nor has it anything to do with physical causality (causality governs events in time, not time itself). Similarly, what is the fundamental difference between moving left and moving right?

These questions cannot be answered by logic or physical causes; their answers must be directly, intuitively apprehended.

This is the Principle of Sufficient Reason of Being: It is the absolute law dictating that the structures of time (and mathematics) and space (and geometry) must necessarily be exactly as they are.

4. The Principle of Sufficient Reason of Acting (The Law of Motivation)

"Motivation is causality seen from within."

"With every decision we perceive—whether made by others or by ourselves—we feel justified in asking 'Why?' That is to say, we assume that something must have preceded the decision, out of which it arose, and this something we call the ground of the ensuing action, or more accurately, the motive. Without such a motive, making a decision is as inconceivable to us as a lifeless object moving without being pushed or pulled." — On the Fourfold Root, §43

The first three principles (Causality, Logic, and Space/Time) are the tools we use when observing the external world. The fourth principle is unique: it is the law we use when we look inward to examine our own inner world and the driving forces behind our actions.