Anaxagoras Philosophy Explained: Nous, Infinite Seeds & Greek Cosmology

Learn Anaxagoras’ key ideas — Nous (Mind), infinite seeds, theory of mixture, and his influence on Greek cosmology and the rise of philosophy in Athens.

Table of Contents:

Anaxagoras: Life and Background

Anaxagoras was born around 500 BC and died in 428 BC.
He was originally from Clazomenae, an Ionian city, but later moved to Athens.
He lived in Athens for about 30 years before being exiled.
In Athens, he faced charges of impiety (insulting the traditional gods).
He claimed that the sun is a burning stone and the moon is part of the earth, not divine beings.
Since Athenians worshipped the sun and moon as gods, this was considered offensive.
The outcome of his trial is unclear — some say he was imprisoned, later released, and moved to Lampsacus, another Ionian city.
Anaxagoras wrote a book, parts of which still survive, giving insight into his philosophy.
His philosophy, however, has many difficulties — possibly due to inconsistencies or misunderstanding over time.
The lecture connects his ideas to Empedocles, who said the world is made of four eternal elements — earth, air, fire, and water, combined or separated by love and strife.

Summary:
Anaxagoras, an Ionian philosopher who lived in Athens, challenged traditional Greek religious views by explaining the sun and moon scientifically. Accused of impiety, he left Athens for Lampsacus. Though only fragments of his writings survive, they reveal a complex and sometimes inconsistent philosophy that followed thinkers like Empedocles.

Anaxagoras’ Critique of Empedocles

Anaxagoras was the first philosopher to criticize Empedocles.
He rejected Empedocles’ idea of four elements (earth, air, fire, water) as the ultimate reality.
Instead, Anaxagoras proposed that reality is made of infinite elements, which he called “seeds” (spermata).
Each seed has its own unique qualities — shape, taste, color, and nature — completely different from others.
All things in the world are formed through the mixture of these countless seeds.
His reasoning was similar to Anaximander’s criticism of Thales — just as everything cannot come from only water, everything also cannot come from just four elements.
He argued, “How can hair come from what is not hair, or flesh from what is not flesh?” — meaning true transformation is impossible.
Like Parmenides, he believed that one thing cannot turn into another; what is not “hair” can never become “hair.”
Therefore, Anaxagoras concluded that change is not transformation but rearrangement of existing seeds.

Summary:
Anaxagoras disagreed with Empedocles’ four-element theory, saying reality consists of infinite “seeds,” each with its own qualities. He reasoned that one substance cannot turn into another — hair cannot come from what is not hair — so all visible change is just a new combination of eternal seeds.

Anaxagoras on the Nature of Change

The central idea in Anaxagoras’ philosophy is his denial of transformation as real change.
Like Parmenides, he argued that true change — one substance turning into another — is impossible.
For example, water cannot become fire, and earth cannot become a tree or an animal.
He asked: if an element does not contain a quality, how can that quality appear by simply combining elements?
According to him, elements never transform, but their mixtures can rearrange to form new things.
So, change means rearrangement or recombination of eternal elements, not creation of new substances.
This idea explains why the basic elements remain constant while their combinations produce variety in the world.
However, Anaxagoras faced a problem: in everyday life, we clearly see change happening — grass turns into milk, milk becomes ghee.
He needed to explain how such visible change is possible if transformation is impossible.

Summary:
Anaxagoras denied that one element could transform into another. Instead, he saw change as the rearrangement of eternal elements or “seeds.” Yet, this created a challenge — if transformation isn’t real, how do we explain everyday changes like grass becoming milk? This question shaped the next step in his philosophy.

Anaxagoras’ Three Premises of Reality

To solve the problem of visible change, Anaxagoras proposed three main premises.
First premise: The entire world is made of an eternal substance — something that has always existed and will always remain.
Second premise: This eternal stuff is a mixture of infinite seeds (spermata) — countless tiny elements that make up everything.
Every object in the universe already contains all kinds of seeds within it.
Hence, Anaxagoras said: “In everything there is a portion of everything.”
Third premise: Motion exists, and it is motion that causes the mixing and separation of these seeds, producing different things.
Thus, ultimate reality is not made of one, two, or four elements, but of infinite changeless seeds, all eternal like Parmenides’ being.
Every object is just a different mixture of these seeds — even a tiny part of anything contains all seeds within it.
For example, grass doesn’t turn into milk; instead, milk’s elements already exist in the grass, and motion simply brings them out.
Similarly, milk contains the elements of ghee, which appear through further rearrangement.

Summary:
Anaxagoras explained visible change through three ideas: the world is eternal, it’s made of infinite seeds, and motion rearranges these seeds. Nothing truly transforms — each substance already contains all others in minute form. So, grass becomes milk not by changing, but because milk’s elements were already within it.

Why Things Look Different: “Everything is in Everything”

Anaxagoras explained that although all things contain all elements, they appear different because the proportion of seeds varies.
For example, grass has all infinite seeds within it, but grass seeds dominate — so it looks like grass.
Milk also contains every kind of seed, yet milk’s elements are present in higher quantity, so we see milk.
The dominant proportion of a certain type of seed gives each object its visible identity.
He likely drew inspiration from mining — where a single stone may contain gold, copper, and silver, but whichever element is most abundant determines what we notice first.
Similarly, in nutrition, an apple contains water, fiber, iron, calcium, and vitamins, yet it still looks like an apple because apple elements dominate.
So, no object transforms into another; instead, each already contains all other elements in smaller amounts.
This leads to Anaxagoras’ bold claim: “Everything is in everything.”
It means every object in the universe is a microcosm of all existence, defined only by which seeds are most present.

Summary:
Anaxagoras believed things appear different because of the varying proportions of infinite seeds within them. Each object has all elements, but one type dominates — making grass look like grass or milk look like milk. His idea, summed up as “everything is in everything,” means all substances contain traces of all others.

The Concept of Nous (Mind) in Anaxagoras’ Philosophy

Anaxagoras rejected Empedocles’ four elements, claiming that infinite, eternal, and qualitatively different elements make up the universe.
To explain movement and order among these infinite seeds, he introduced the idea of Nous — meaning Mind, Intellect, or Reason.
Just as Empedocles used Love and Strife as forces of combination and separation, Anaxagoras used Nous as the ordering principle of the cosmos.
He described Nous as the “thinnest of all things”, pure, unmixed, and all-knowing — it knows and directs everything.
Nous maintains cosmic order by guiding and moving all seeds into proper arrangements.
According to Anaxagoras, Nous exists within living beings — humans, animals, and plants — giving them inner direction and life.
Non-living things do not have Nous inside them, but Nous still controls them externally.
He believed the same Nous is present in all living beings; differences arise due to variations in physical bodies.
For example, just as the same electricity powers both a fan and a laptop, but they perform different functions, the same Nous acts differently in humans and trees.
Anaxagoras was among the first thinkers to clearly distinguish between living and non-living beings through the idea of an inner mind or intelligence.

Summary:
Anaxagoras introduced Nous (Mind) as the intelligent force that organizes and moves the infinite seeds of reality. It is pure, all-knowing, and present in all living beings, giving them inner life and order. Though the same in essence, Nous acts differently depending on the physical form — making it the first clear link between mind and matter in early Greek philosophy.

Confusions About Nous in Anaxagoras’ Philosophy

There are two major confusions in Anaxagoras’ concept of Nous (Mind).
First confusion: Is Nous material or immaterial?
- It behaves like a force or process that moves the seeds in a rational and orderly way.
- Yet, when Anaxagoras describes it, he sometimes makes it sound like a substance, similar to material things like gold or iron.
- This creates debate — is Nous a physical entity or a non-material guiding principle?
Second confusion: Does Nous act with purpose or randomly?
- Nous moves the seeds, but Anaxagoras never clearly says why it moves them.
- Is it like wind blowing papers around without purpose, or like a person arranging them with intention?
- Both seem present in his writings — at times Nous appears purposeful, at other times mechanical or random.
This uncertainty — whether Nous is a conscious intelligence or a natural force — becomes an important issue for later philosophers, especially Aristotle, who tried to clarify its meaning.

Summary:
Anaxagoras’ Nous raises two big questions: Is it a material or immaterial force, and does it act with purpose or randomly? Though he introduced Nous as the rational mover of the cosmos, his writings leave both points unclear — a gap that later philosophers, including Aristotle, sought to resolve.

The Idea of Ultimate and Indestructible Matter

Both Anaxagoras and Empedocles believed that ultimate matter is indestructible, but Anaxagoras rejected Empedocles’ four elements as the final reality.
He argued that earth, air, fire, and water cannot be the ultimate or eternal substances.
To define what truly indestructible matter means, Anaxagoras gave a clear principle:
- An element is ultimate if, when divided into smaller parts, each part has the same quality as the whole.
In other words, dividing the substance does not change its nature or quality.
For example, if you divide a block of gold into many smaller pieces, each piece remains gold — the quality stays the same.
But if you divide a living cat into parts, the parts do not remain cats — their nature and function disappear.
Similarly, cutting a laptop into two parts doesn’t give you two smaller laptops; its functional quality is lost.
Therefore, only that matter whose parts preserve the same nature as the whole can be called ultimate, eternal, and indestructible.
According to Anaxagoras, such seeds (spermata) form the true foundation of all reality.

Summary:
Anaxagoras defined the ultimate element as one whose parts retain the same quality as the whole — division doesn’t change its nature. Unlike a cat or a laptop, which lose their function when divided, substances like gold stay the same in every fragment. These unchanging, self-similar seeds are what he called the true, indestructible matter of the universe.

Aristotle’s Homoiomeros and Anaxagoras’ Primordial Mixture

Aristotle later named Anaxagoras’ idea of ultimate elements as “Homoiomeros” — meaning substances whose parts and whole share the same quality.
A Homoiomeros element remains unchanged in quality when divided, such as pure gold.
Anaxagoras believed that, in the beginning, the entire world was a complete mixture containing all eternal seeds.
This primordial mixture was perfectly balanced and uniform, with no single seed dominant over others.
Because of this equal proportion, the mixture had no distinct quality or form — it was a featureless totality.
He was likely responding to Anaximander’s idea of the “boundless” (apeiron), which was also an undefined source of all things.
However, unlike Anaximander’s one boundless substance, Anaxagoras’ mixture contained many distinct seeds — each eternal and unique in quality.
He explained that if all elements exist in equal proportion, then no particular quality can appear — our senses cannot detect any one element.
Just as we see grass as green only because grass elements dominate, a perfectly balanced mixture would appear as nothing specific.
In this way, Anaxagoras solved the problem of how the world could begin from something that has no specific property or form.

Summary:
Aristotle called Anaxagoras’ eternal, self-similar elements Homoiomeros. Anaxagoras taught that the universe began as a perfectly uniform mixture of infinite seeds, where no element dominated. Because all were in equal proportion, this original state had no distinct qualities — a balanced, neutral beginning from which order later emerged.

The Role of Nous and Problems in Anaxagoras’ Philosophy

In Anaxagoras’ view, the primordial mixture was completely uniform until Nous (Mind) entered it from outside.
Just as Empedocles’ Love and Strife caused motion and change, Nous acted as the initiating force in Anaxagoras’ cosmos.
Nous set the mixture into circular motion, which caused the seeds to separate from one another.
As this separation began, the mixture spread out through space, forming the ordered universe.
However, the process of separation was never complete — elements are still partially mixed with one another.
Anaxagoras said: “There are many portions in many things, but no thing is altogether separated or distinguished from anything else.”
This means that no object is purely one element — everything remains a partial mixture of all seeds.

Philosophical Problems in His Theory

Anaxagoras believed that matter is infinitely divisible — you can divide it endlessly, but there is no smallest part.
This idea contradicts atomic theory, which holds that matter is made up of indivisible particles (atoms).
In atomic theory, division ends at the smallest possible unit, but in Anaxagoras’ system, division never ends.
This concept is similar to Zeno’s philosophy, where space and distance can also be infinitely divided.
Thus, while Anaxagoras introduced a powerful idea of Nous as an organizing mind, his view of infinite divisibility created logical and physical difficulties in explaining matter.

Summary:
Anaxagoras taught that the universe began as a uniform mixture until Nous (Mind) entered and set it into motion, separating its elements to form the cosmos. Yet, he maintained that nothing is ever fully separated — everything remains mixed. His belief in infinite divisibility opposed atomic theory and raised unresolved philosophical problems about the nature of matter.

The Inconsistency in Anaxagoras’ Theory of Mixture

Anaxagoras maintained that the separation of the cosmic mixture is still incomplete — meaning nothing exists in pure form.
This fits with his famous claim that “everything is in everything.”
According to him, every object contains all kinds of seeds, but we identify an object based on which seed type dominates.
For example, a piece of gold contains not only gold seeds, but also iron, copper, and other seeds in smaller amounts.
Because gold seeds dominate, our senses recognize it as gold.
However, this leads to a logical contradiction: if pure gold particles truly exist within the mixture, then they cannot contain other seeds.
But if everything contains everything, then even those gold particles must include other elements too.
These two ideas —
1. “Everything is in everything” (no pure substance), and
2. “There are pure gold particles” (pure substance exists) —
  cannot both be true at once.
This contradiction shows an inconsistency in Anaxagoras’ theory: he wanted both universal mixture and distinct pure elements, which logically conflict with each other.

Summary:
Anaxagoras’ belief that “everything is in everything” clashes with his idea that pure particles, like pure gold, exist. If everything remains mixed, nothing can be pure — but if pure elements exist, then not everything is in everything. This tension reveals a major inconsistency within his philosophy of infinite mixture.

Anaxagoras’ Scientific and Cosmological Ideas

Anaxagoras also made several natural and scientific observations beyond his metaphysical theory.
He believed that the Earth is flat, and that air supports it — when the air moves or shifts, earthquakes occur.
This idea of air supporting the Earth was also shared by another early philosopher (students are often asked to recall his name!).
He explained that river water comes from rain, and rainwater flows into the sea — a clear hydrological cycle understanding.
Remarkably, Anaxagoras gave the correct explanation of solar and lunar eclipses — they occur due to the blocking of light between the Sun, Moon, and Earth.
He also stated that the Moon has no light of its own; it reflects the Sun’s light, which was a groundbreaking idea for his time.
He further claimed that the Moon is like the Earth — not a smooth divine body, but one with mountains, valleys, and craters.
These scientific insights show that Anaxagoras was among the first thinkers to apply reason to natural phenomena, moving beyond mythological explanations.
Some modern writers even compare his cosmology to the Big Bang theory, since he described a primordial mixture set into motion by Nous, leading to the separation and formation of the universe.

Summary:
Anaxagoras combined philosophy with early scientific thought. He proposed that air supports the flat Earth, explained eclipses correctly, and understood the Moon’s light as reflected from the Sun. His view of a rotating cosmic mixture initiated by Nous resembles a primitive form of the Big Bang idea, making him a key link between mythic thought and rational cosmology.

Anaxagoras’ Cosmology and His Impact on Athens

In his cosmology, Anaxagoras said the primordial mixture was infinitely small and compact in the beginning.
Due to the action of Nous (Mind), this mixture began to expand and separate, continuously spreading outward.
As the mixture kept expanding, it suggested a process similar to the modern Big Bang theory, where the universe grows from an initial dense point.
Some modern scholars therefore compare Anaxagoras’ cosmology to the Big Bang, noting the resemblance in its idea of expansion from unity to diversity.
Anaxagoras also hinted at a multiverse concept — he argued that if separation happened here, it could also happen elsewhere in the cosmos.
Thus, he suggested that other worlds like ours could exist — an early form of the multiverse idea, later expanded by an Italian philosopher.
A crucial historical point: Anaxagoras was the first philosopher to live in Athens, though originally from Ionia.
Ionia was already known for its scientific and rational thinking, shaped by figures like Thales and Anaximander.
By bringing Ionian rationalism to Athens, Anaxagoras introduced scientific and logical inquiry into a city deeply rooted in religion and tradition.
His influence helped transform Athens into the intellectual and philosophical center of the ancient Greek world.

Summary:
Anaxagoras described a universe expanding from an infinitely compact mixture under the motion of Nous, a vision resembling the Big Bang and even hinting at the multiverse. As the first philosopher in Athens, he carried Ionian scientific thought into a religious society, laying the foundation for Athens’ rise as the center of philosophy and rational inquiry.

Evaluation of Anaxagoras’ Philosophy and Legacy

The theory of infinite seeds or elements proposed by Anaxagoras was seen as overly complex and less useful.
Earlier philosophers, from Thales onward, tried to simplify reality — to find one unifying principle that the human mind could understand.
In contrast, Anaxagoras’ idea suggested that there are as many elements as there are objects — grass, milk, gold, iron, skin, hair, bone, each having its own distinct element.
Such a system makes the world more complex, not simpler, failing to offer the unity philosophers sought.
However, his concept of Nous (Mind) stands out as a valuable contribution.
Unlike Empedocles, who used two forces (Love and Strife) to explain motion, Anaxagoras used only one principle — Nous.
Yet, thinkers like Socrates and Aristotle criticized him, saying Nous was only a “filler concept” — an idea used when he couldn’t otherwise explain the cause of motion.
Despite this, Nous later became influential, inspiring philosophical discussions about the relationship between mind and matter.
This concept eventually led to the idea of dualism, raising deeper questions:
- Can the world be explained only by matter, or do we also need something non-material, like mind or reason?
Thus, while his theory of infinite seeds may not have endured, Anaxagoras’ idea of Nous became a key step in the evolution of philosophical thought.

Summary:
Anaxagoras’ theory of infinite elements failed to simplify reality, but his concept of Nous (Mind) profoundly influenced later philosophy. Though seen by Socrates and Aristotle as a mere filler, Nous opened the path to exploring the dualism of mind and matter — a question that shaped much of Western philosophical thought.

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