The idea that there is a difference between “science” and “philosophy” is a very recent one, in many ways dating to the eighteenth century CE (i.e. only about 300 years ago). The word “philosophy” literally means “love of knowledge,” and in the ancient world the people we might identify as Greek “scientists” were simply regarded as philosophers by their fellow Greeks, ones who happened to be especially interested in how the world worked and what things were made of. These first Greek scientists are today called “Pre-Socratic” philosophers (a label also not coined until the 18th century) due to this connection to their desire for knowledge, and, in fact, science was not considered a separate discipline until the Renaissance; science was called “natural philosophy” before then. This term was also intended to differentiate those who came before Socrates, who offered sustained moral analysis versus the more scientific orientation of the “Pre-Socratics.” (There are, incidentally, many disagreements about the usefulness and meaning of this term.) Unlike earlier thinkers, the Greek scientists sought to understand the operation of the universe on its own terms, without simply writing off the details to the will of the gods.

The underlying assumptions of the early philosophers, the early scientists of Greek culture were:

• There is an intelligible coherence in the phenomenal world
• The universe is an intelligible whole
• There is an order, a cosmos, that underlies the chaos of our perceptions and that
• The Order of the universe is comprehensible to reason

In the works of the pre-socratics there is obviously the progression from mythopoetic thought to a primitive scientific thinking in the form of speculative inquiry and from that form of thought to philosophy as rational inquiry. These thinker were searching for the ARCHE or the very first or most fundamental principles or causes. They wondered about the immanent and lasting ground for existence. They were critical of the cosmogony they had in the mythopoetic tales. They were looking for a cosmology (an explanation for the order of the universe) that did not rely on the gods.

They did not base their thinking on belief but on reason.

These thinkers were naturalists and materialists as they sought answers to physical questions that were rooted in the physical itself. They were looking for the stuff out of which the universe was composed and they wanted an answer that was itself made of the same stuff. The matter of the universe would have its explanation in matter. They were, for the most part, materialists, rejecting spiritual or religious explanations for the causes and stuff of the universe.

The Milesians (Ionians): 7th-6th Centuries B.C.

Thales (625-545 BC) was looking for the basic stuff (physis) out of which all else is made. He expressed his idea concerning the basic stuff in his claim that “All things are made of WATER”! Now at first you might think that his idea is pretty silly and definitely wrong, however, that would be the wrong approach. What do you suppose was meant by that claim? Thales was attempting to express an idea at a time when his language was not developed to the point where he could express an abstraction. We are accustomed to thinking in abstraction and we are that way in part because we have a language with many words that are linked with abstractions.  The Greeks at this time did not have that to work with.  For example, if someone wanted to call for justice, they would call upon the goddess who in their tales represented what today we consider in the abstract as justice. So instead of saying” I want justice” or “Give me justice” they might say something of this sort ”May the goddess Themis settle this by sending us a sign”

Thales claim is most likely the claim that there is “Unity in Difference”! In other words, Thales was attempting to claim that there was some basic stuff out of which all things are made.  He selects water perhaps because it has properties which enable all the people of his time and our time to experience water in three different states: Liquid, solid and gas. Now if one thing such as water can exist in three very different forms then there must be something , like water, that is the basic stuff, physis, of the universe. Today, scientists make a similar claim. All reality, all that exists in the universe is made of or composed of or manifests as: energy. So from Thales comes the idea that no matter how things may appear, all things are made up of the same stuff: Everything is one thing!

Anaximander (612-545 BC) rejected Thales basic stuff, water, and speculated that the ultimate reality could not be identified with any one particular element. He came up with the basic stuff being the  BOUNDLESS or the INFINITE or the UNLIMITED. This basic stuff was infinite and without a beginning. He also conceived of the theory of species evolving from one another through time in response to the need to adapt. He thought of the earth as revolving. He speculated that all life originated in the sea and moved onto the land. With this thinker abstraction and materialism developed further.

Anaximenes (585-528 BC) hypothesized that it was not water but AIR that was the fundamental stuff of the universe and that air can be condensed or rarefied to take on the properties of what appear to be other elements. He sought to simplify and clarify the model of the universe.

The Ionians: 6th-5th Centuries B.C.

Pythagoras (580-496 BC) not only quests after the basic stuff of the universe but his works reveal that he explored truth itself and the idea of the good life; questions of ethics. He was concerned with the nature of reality and of life. He developed spiritualism in contrast to the materialist schools of his time. He was a mathematician, spiritualist, mystic, musician and leader of a cult. His fundamental contribution to the world of thought was that the world is really not material at all but made up of NUMBERS. Numbers are things and in some way constitute the essence of reality. All things are, despite appearances, made up of numbers. The original number, the ONE, being as with fire, is in motion and set all else into being. He was inspired in this mode of thought by his observations. The sound made by a string pulled tight and picked will vary with its length. So he thought the amount of a thing leads to its properties and its very being. His is a naturalistic explanation. How far off is it from contemporary science which instructs us that all things are made up of energy and take on different properties depending on the amount of energy. Consider that the difference between hydrogen and oxygen is the number of protons in the nucleus of the atoms of each.

The more important contribution made by Pythagoras was in his thinking that is to be in what is reached by REASON over and against what is given to the senses. Truth is reached through reasoning. Reasoning reveals that mathematics is in all things. Numbers relate to shapes and all that exist has or takes on shape. The individual who develops reason is on the correct path for the truth and the path to realize the proper destiny for the reasoning soul. Reason is the source of the world itself. Pythagoras taught that people should surrender to their higher self, the soul, the reasoner. It is the reasoning part of the person that can contact reason itself, the LOGOS, or universal reason that generates the universe. The reasoning principle is in all things. For Pythagoras that principle, god, is the hidden measure in all that is real.

Heraclitus (535-475 BC) believed that all things are in perpetual flux. BECOMING is the basis for all that is real. BEING is unreal. All is changing. Permanence is an illusion. All things are one and one-in-many. That which is the essence of all is FIRE. The LOGOS is the universal principle of reason through which there is a law like process in the universe that provides its existence and order.

Empedocles (492—432 BC) conjectured that there are four basic elements: EARTH, AIR, FIRE and WATER. They were moved about by the two basic forces: LOVE and STRIFE. Together these ideas explained everything that was physical.

The Eleatics: 6th-5th Century B.C

Parmenides (540-470 BC) taught that all that is has always been and always will be. Reality is that which never changes. Reality is BEING  and not becoming. Changelessness is the nature of all reality.  This is not at all obvious to our senses. Parmenides trusted in his reason over his senses. The appearance of things can be deceiving, so trust in reason. All change is illusion for Parmenides!  Change can not be real. The truth is what is arrived at by thought and the truth is set over and against opinions based upon sense impressions and common beliefs. The REAL is changeless.

So with Parmenides Philosophy comes to trust in REASON over the senses. His thought liberates reason from the senses. There is in his work the recognition of the autonomy of thought and the use of independent criteria for judging thought; namely, coherency & consistency over probability.

The Atomists: 5th-4th Century B.C.

Anaxagoras (500-428 BC) appears to have taught that all that is can be explained with a combination of NOUS and MATTER. For him the universe of matter was set into its form and motions by Nous or MIND. This mind is immortal, homogeneous, omnipotent, omniscient and orders all phenomena. He did not believe in gods and goddesses. He did not think that the sun was a god and the moon a goddess. He thought the sun was a ball of fire and the moon  a rock which reflected light from the sun. He was to be executed for blasphemy by the Athenians but escaped to another land. Socrates was interested in his theories until Socrates learned that for Anaxagoras the NOUS acted at the beginning of the universe, setting all in motion, and was not invoked by Anaxagoras to explain motions including those of humans. Socrates was to focus on the actions of humans and believed that their minds had a great deal to do with their actions.

Leucippus (450 BC) and Democritus (460-370 BC) believed that there were an infinite number of ever moving ATOMS (indivisible-not separable) that composed all that is. Each was imperceptible. The atoms exist in a void. They move and interact through necessity and chance.

The Sophists: 5th-4th Century B.C.

Most of early Greek philosophy prior to the Sophists was 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 interests. The Sophists were the first professional educators. For a fee, they taught students how to argue for the practical purpose of persuading others and winning their way. While they were well acquainted with and taught the theories of philosophers, they were less concerned with inquiry and discovery than with persuasion.

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 their entrepreneurial interest in teaching argument for the sake of best serving their client’s interests leads Plato to derisively label the Sophists as “shopkeepers with spiritual wares.”

One of the better known Sophists, Protagoras (481-411 B.C.), authored several books including, 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. This is a classic expression of epistemic relativism. Accordingly, Protagoras rejects any objectively knowable morality and takes ethics and law to be conventional inventions of civilizations, binding only within societies and holding only relative to societies.