The Presocratics


Pre-philosophical mythology in ancient Greece


The early Ionian epic poet Homer had given an account of the world as under the influence of the Olympian gods.  The Olympian gods were much like humans, capricious and willful.  In the Homeric view of the world, human qualities are projected onto the world via human like gods.  Here explanation of the natural world is modeled on explanation of human behavior


The Milesian's



The beginning of philosophy in ancient Greece is often given as 585 BC, the year that the first Milesian philosopher, Thales, predicted a solar eclipse.  Thales brings a new naturalistic scientific approach to explaining the world.  There is no distinction between science and philosophy at the beginning (or, arguably for that matter, throughout the ancient Greek tradition).


Thales holds that water is the fundamental substance of the world.  All things are ultimately constituted of water.  While this view is certainly false and sounds absurd to us, the significant contribution offered by Thales is not the answer but the question and how Thales proposed to answer it.  Prior to this, answer questions about the ultimate nature of the worlds would be given in terms of the supernatural.  Thales takes an important step away from mythology and superstition, a step away from projecting ourselves onto the world.  Thales poses a question that invites intellectual investigation of the world, as it is independent of the will of humans.

Thales recognizes that the world is not just what it appears to be and asks about its fundamental nature.  Change is apparent.  Thales asks about the nature of that which endures change.  What is the nature of the underlying substance that goes through changes?  The question here raises a metaphysical issue and does so in a way that invites rational investigation rather than mere speculation or appeal to myth and the supernatural.

Thales and the olive presses, practical value of philosophy.





Anaximder argues that the fundamental stuff of the world is not identical with any of the known elements, but is rather "the indeterminate boundless".  Anaximander anticipates the theory of evolution.  He holds that humans and other animals evolved from fish.  Anaximander takes all change to be the product of "injustice", or imbalances among the basic elements: earth air fire and water.



According to Anaximenes, the basic stuff of the world is air.  It is both boundless as is underlying reality according to Anaximander, and specific, one of the four elements, as on Thales view.




Pythagoras  (fl. 525-500 BC)

Pythagoras traveled in Egypt where he learned astronomy and geometry.


All things consist of numbers

Mathematics as purifier of the soul

Thinking about numbers takes one's attention off of particular things and elevates mind to the realm of the eternal.


Pythagorean theorem:  square of the hypotenuse of a right triangle equal to the sum of the squares of the remaining sides.


Music - noted relations between tones and numbers. 

Octave  - 2:1 ratio


Points and dimension suggests correlation between number and magnitude (extension, form etc.)

1 point defines location

2 points define line

3 points define planes

4 points define solid 3 dimensional magnitude.


Pythagoras introduces the concept of form.  The earlier Milesians only addressed the nature of matter.  They asked what is the stuff of the universe.  A full account of the nature of the world must also address that the various forms that underlying stuff takes. 

Form implies limits.  For Pythagoras, this is understandable in numerical terms.

Number represents the application of limit (form) to the unlimited (matter)

The notion of form takes on greater sophistication and importance in the philosophy of Plato.



The Homeric Gods are not sources of salvation or spiritual purification.  They are, like humans, capricious and willful. (Though they do punish mortals for their hubris.  Humility is a virtue in ancient Greece - and in every intellectually vibrant society.  By contrast, the true “power of pride” is to breed vanity and ignorance)


There was Dionysian religion, which sought spiritual purification and immortality through drunken carnal feasts and orgies. 


Pythagorean religion aims at spiritual purification and immortality.


Pythagoras argued that there are three kinds of men, just as there are three classes of strangers who come to the Olympic games. The lowest consists of those who come to buy and sell, and next above them are those who come to compete. Best of all are those who simply come to look on. Men may be classified accordingly as lovers of gain, lovers of honor, and lovers of wisdom. That seems to suggest the doctrine of the tripartite soul, which is sometimes attributed to the Pythagoreans, though it is common now to attribute that doctrine to Plato.


Phythagoras founded a religious society based on the following precepts:



(1) that at its deepest level, reality is mathematical in nature,

(2) that philosophy can be used for spiritual purification,

(3) that the soul can rise to union with the divine,

(4) that certain symbols have a mystical significance, and

(5) that all brothers of the order should observe strict loyalty and secrecy.


Members of the inner circle were strict communist vegetarians.  They were also not allowed to eat beans.



Heraclitus(544-484 bc) 

Heraclitus was born in Ephesus on the coast of Asia Minor.  He is best known for his doctrine of eternal flux according to which everything undergoes perpetual change.  “One can never step in the same river twice.”  Like Xenophanes, he thinks of nature as a unified whole and thereby skirts problems of coming to be and passing away.  The underlying substance of the world is fire or heat according to Heraclitus.  This is the least stable of the elements and explains the transitoriness of all things.  Everything is a kindling or extinguishing of fire.  While everything is in a continual state of flux, this change is not without order.  Heraclitus saw a Logos or rational order as essential to the world.  Changes are injustices, which by natural necessity are redressed in further changes.  Heraclitus held ethical views worth noting as well. The good life involves understanding and accepting the necessity of strife and change. Strife and conflict are to be accepted not regretted (see fr. 43 44 62).  The soul of a human is part of the divine fire.  The purer (drier) it is the better.  Other notable fragments 105



The Eleatics

Xenophanes (570 – 475 bc)

Xenophanes main metaphysical work is “On Nature”.  Here he advances the thesis that all is one and therefore unchangeable. Xenophanes is also important as an anthropologist in adopting the view that agriculture, the use of fire, the technology for making wine, etc. were historical intellectual developments of human civilization rather than gifts from the gods. His philosophy of religion is also significant.  Xenophanes thinks that humans project their own image onto their gods.  But he does not infer atheism from this.  Rather, he recognizes divinity in the impersonal unchangeable unity.  The one is deified, so we have a sort of pantheism.


Parminides (540 – 470 bc)

Parminides rejects Heraclitus and agrees with Xenophanes on the unity and unchangeability of all being.  Being (existing matter) is everywhere indivisible and the same, motionless and unchangeable.  Reason gives us the only true idea of the world as unchanging being.  The senses mislead us in presenting the world as manifold and changing.  This view demands an “error theory”, an explanation of the ordinary person’s apparent experience of change and diversity.  In our ordinary experience of the world, our senses erroneously place Not-Being on a-par with being.  We get our perceptions of individual things by representing them as separated by empty space (which is Not-Being).  But in reality, there is no Not-Being.


Zeno (born between 495 and 490 bc)

Zeno was a student of Parmenides. He offered a series of arguments against the possibility of motion and of a multiplicity of things.


The Sophists

Most of early Greek philosophy prior to the Sophists were concerned with the natural world.  The desire to explain an underlying reality required natural philosophers to speculate beyond what is observable.  And they lacked any developed critical method for adjudicating between rival theories of substance change or being.  In this situation, it is easy to see how many might grow impatient with natural philosophy and adopt the skeptical view that reason simply cannot reveal truths beyond our immediate experience.  But reason might still have practical value in that it allows the skilled arguer to advance his political interests.  The Sophists were the first professional educators.  For a fee, they taught students how to argue for the practical end of winning their case.  While they were well acquainted with and taught the theories of philosophers, they were less concerned with inquiry and discovery than with persuasion.

Earlier Milesian philosophers were primarily interested in knowledge of the natural world.  Pythagoras and Heraclitus had offered some views on religion and the good life.  Social and moral issues come to occupy the center of attention for the Sophists.  Their tendency towards skepticism about the capacity of reason to reveal truth and their cosmopolitan circumstances which exposed them to a broad range of social customs and codes, lead the Sophists to take a relativist stance on ethical matters.  The Sophist’s lack of interest in knowing the truth for its own sake and entrepreneurial interest in teaching argument for the sake of best serving their clients interests leads Plato to derisively label the Sophists “shopkeepers with spiritual wares”



Protagoras (481-411)

Protagoras comes from Abdera.  Protagoras authored several books.  The most important of these is “Truth, or the Rejection” (the rejection of science and philosophy) which begins with his best-known quote:  “man is the measure of all things, of those that are that they are, of those that are not that they are not”.  Knowledge, for Protagoras is reducible to perception.  Since different individuals perceive the same things in different ways, knowledge is relative to the knower.  Accordingly, Protagoras rejects any objectively knowable morality and takes ethics and law to be conventional inventions of civilizations and binding only within societies.