Seeking a Systematic and Unified Ontology: Thales Looks for the Foundational Principle of Physical Reality

The first philosophers in the history of the world are grouped together as Presocratics. Among the Presocratics are several subgroups, the earliest of which is the Milesians. Among the Milesians, the initial individual was a man named Thales. He did his work around 600 B.C., give or take a decade. So he was the first of the first of the first.

As Donald Palmer writes:

Philosophy makes its first self-presentation in three consecutive generations of thinkers from the little colony of Miletus on the coast of Asia Minor — today’s Turkey — in the sixth century.

The first recorded philosopher is Thales of Miletus.

Apparently, he did not write a book, or if he did, it is long lost.

So, this most fascinating fellow — potentially the world’s first philosophy — did not leave directly anything for modern readers. How does one know about him? What did he think?

Although there is no major text written by Thales left for us, there are a few dubious and sketchy quotes. Most of those are recorded in books written by Aristotle, who wrote about three hundred years after Thales. Donald Palmer reports:

If we can trust Aristotle and his commentators, Thales’s argument was was something like this:

If there is change, there must be some thing that changes, yet does not change. There must be a unity behind the apparent plurality of things, a Oneness disguised by the superficial plurality of the world. Otherwise the world would not be a world; rather, it would be a disjointed grouping of unrelated fragments.

So what is the nature of this unifying, ultimately unchanging substance that is disguised from us by the appearance of constant change?

Thales was looking for a unifying and systematic principle behind physical reality — behind the phenomena which people detect with their five senses. What is the basic and foundational stuff of the world? Of the universe?

The questions which Thales posed are not that much different than the questions of modern physics more than 2,000 years later. The search for a unifying principle behind all forms of matter is the essence of subatomic physics. Likewise, the search for a unity behind all forms of energy, and eventually, behind both matter and energy, is a common theme among the great physicists of the past, present, and foreseeable future.

The physicists of the modern age look to various and increasingly smaller subatomic particles, look to a continuum of electromagnetic energy, and look to equations like Einstein’s to encompass both matter and energy.

Thales looked to something rather common yet remarkably subtle. He wondered if the underlying principle of all physical reality might be water.

It’s easy to dismiss Thales as simple-minded, primitive, or naive. But the reader might consider his choice more patiently. Water is one of the few things which is readily experienced in all three states: solid, liquid, and gas. Water constitutes the majority of the earth’s surface: 75% by some accounts. Water is also essential to all known forms of life, and constitutes a majority of the bodies of all known plants and animals.

So Thales could have done worse.

In addition to seeking a unifying and systematic principle for the sensible world, Thales was also trying to develop a conceptual explanation of that world, an explanation that would add a layer of depth beyond the already-available mythological explanations.

Contrary to the current casual usage of the word, ‘myth’ does not refer exclusively to falsehood. There are true myths. A myth is an explanation by means of a narrative. True myths give an accurate explanation of some aspect of reality, but they often give an incomplete explanation. They are true but incomplete.

Thales, his fellow Milesians, and the Presocratics generally, sought to give conceptual explanations of the physical world around them. This is why their early philosophy is often so closely bound to physics. There was no sharp distinction between physics and philosophy in those days.

Thales thought that everything was water. Modern physicists think that everything is atoms or subatomic particles. The difference may not be so large.

The Unreliable Sources for Reliably Influential Inventiveness: The Obscure But Powerful Effect of Presocratic Thought

The good news about the Presocratic philosophers is that they are among the most thought-provoking, creative, and inventive thinkers in the history of philosophy. The bad news is that they are among the worst-documented authors ever.

That means that modern readers have very little information about them, and very little reliable information about exactly what they wrote or hypothesized. As Donald Palmer writes, “the problem is that in fact very little is known about the pre-Socratic philosophers. Most of the books that they wrote had already disappeared by the time that the philosopher Aristotle” summarized and explained their views.

Aristotle, who lived from 384 B.C. to 322 B.C., “tried to catalog and criticize their views.” Aristotle wrote about these Presocratic philosophers, and what they wrote and asserted. The problem is, modern readers can’t be sure of how accurate Aristotle was. Did Aristotle understand the Presocratics correctly? Did he report about them accurately?

Donald Palmer explains:

Today’s understanding of the pre-Socratics is based mostly on summaries of their ideas by Aristotle and by later Greek writers who had heard of their views only by word of mouth. Many of these accounts are surely inaccurate because of distortions caused by repetition over several generations by numerous individuals. (Have you ever played the game called Telephone, in which a complicated message is whispered to a player, who then whispers it to the next player, and so on, until the message — or what’s left of it — is announced to the whole group by the last player in the circle?) Also, these summaries often contained anachronistic ideas, that is, ideas from the later time projected back into the earlier views. Only fragments of the original works remain in most cases today, and even those few existing passages do not always agree with one another. Remember, these “books” were all written by hand on papyrus (a fragile early paper made from the crushed and dried pulp of an Egyptian water plant), and all editions of these books were copied manually by professional scribes. Furthermore, the meaning of many of the fragments is debatable, both because of the “fragmentary” nature of the scraps — key words are missing or illegible — and because of the obscure style and vocabulary in which many of these works were written. Nevertheless, a tradition concerning the meaning of the pre-Socratics had already developed by Aristotle’s time, and it is that version of their story that influenced later philosophers and scientists. Aristotle is not the only source of our information about the pre-Socratics, but unfortunately most of the additional information comes from post-Aristotelian commentators giving interpretations of Aristotle’s remarks. We do not know to what extent the material provided by these other sources is informed by extraneous sources. So Aristotle appears to be our real source, and we have no clear idea of his accuracy because he paraphrases the various pre-Socratics.

Donald Palmer summarizes the situation bluntly: “Therefore, the tradition” which he describes “is flawed and distorted in many ways.”

So, if this data is so garbled, if this information is so distorted, why should modern readers invest their time reading it?

It’s worth wading through these disjointed and obscure texts because the Presocratics started exploring so many questions which lie at the three-way intersection of mathematics, philosophy, and physics. They explored exponential calculations — algebra class before algebra had been discovered — as they investigated rapidly accumulating accelerations and asymptotic curves. They hinted at calculus 2,000 years before Gottfried Wilhelm Leibniz and Isaac Newton discovered calculus.

Scholars continue to explore this tantalizing yet frustrating batch of quotes and snippets from the world’s first philosophers because they directly connect with the most modern, and post-modern, questions about the universe.

Revealing the Foundations of the Universe: The Presocratics Establish Modern Physics

Who were the Presocratics? They were a group of philosophers who did most of their work between 600 B.C. and 400 B.C., give or take a few decades. They did not all live in the same place; they were separated by hundreds of miles, at a time when travel and communication were much slower than they are now.

They did not all know each other, and they certainly did not all agree on many topics. They are divided into a number of different subgroups.

Yet they are all categorized together, and for good reasons. Yes, it’s true that they all — or most of them — did their work prior to the famous career of Socrates. But there is a better reason for lumping them all together. It’s the way they thought — the way they reasoned. Even when they came to different conclusions, they were using similar methods.

Donald Palmer explains that “the thinkers who were active in Greece between” 600 B.C. and 350 B.C. “are known today as the pre-Socratic philosophers, even though the last group so designated were actually contemporaries of Socrates.” Those dates are, of course, approximate, because these kinds of trends fade into, and out of, existence in a gradual way.

While the beginning and ending of a construct like the Presocratic era is fuzzy, the life of Socrates had definite beginning and ending points. Socrates was born in 469 B.C. and died in 399 B.C.

Donald Palmer explains some common threads among the diverse group: “What all the pre-Socratic philosophers have in common is their attempt to create general theories of the cosmos (kosmos is the Greek term for “world”) not simply by repeating the tales of” what happened, but rather explaining why and how it happened.

The Presocratics thought that myths — even when they are true — are not sufficient explanations. A myth is an explanation by means of narrative. A myth can be true or false. In slang and casual speech, ‘myth’ is sometimes used to refer to a falsehood, but that is not its meaning in philosophical discourse. The Presocratics pointed out that, if a conceptual explanation was given in addition to a myth, then the net amount of knowledge and understanding would be greater.

For example: a person might ask about how the first men arrived on the moon and walked around on it. A mythological answer would talk about Wernher von Braun and Neil Armstrong and the Apollo spacecraft, etc.. That myth would be true as far as it went, but it lacks some information.

A conceptual answer would talk about the forces of gravity, how much acceleration a spacecraft needs to reach a certain speed, what the escape velocity is for earth orbit, etc.

The Presocratics wanted to explain physical phenomena, not by giving a narrative, “but by using observation and reason to construct general theories that would explain to the” rational “and curious mind the secrets behind the appearances in the world.” A conceptual answer articulates principles which can be applied beyond the case in question. A mythological answer, even when it’s true, is usually limited to a concrete and specific instance.

Another commonality was that all the pre-Socratic philosophers stemmed from the outlying borders of the Greek world: islands in the Ionian Sea or Greek colonies in Italy or along the coast of Persia (in today’s Turkey).

Some scholars speculate that social life on the edges of the Greek Empire was more interesting than life back home on the Greek mainland, and that this circumstance occasioned the birth of philosophy. This is an interesting hypothesis, with plausible arguments both for and against it.

In any case, “knowledge of these thinkers is tremendously important not only for understanding the Greek world of their time, but” for gaining insights into modern physics, modern mathematics, and modern philosophy. Of course, one must also define when the modern era begins.

One of the reasons that the study of the Presocratics is good “for grasping the origins of” most subsequent “philosophy and science” is that they developed a concept of matter. One might look at different objects: a tree, an iceberg, a distant planet.

Those objects seem dissimilar to one another, but the Presocratics saw that they were all physical objects, and that there is some underlying commonality shared by all physical objects. They are all composed of matter. This is an abstraction. Abstraction is important in philosophy, in physics, and in all rational thought.

The Latin words from which the word ‘abstract’ arises mean to “pull away” or to “take off.” In abstraction, the thinker “pulls away” a concept or a principle from the specific instance in which she or he finds it. Having separated the concept from the context, she or he can then apply that concept elsewhere — or everywhere.

The Presocratics developed a way of understanding the universe which was systematic and unified. Their understanding revealed an underlying structure to reality which made modern physics possible. This understanding included that reality is intelligible, i.e., that it can be understood; that some laws of nature are universal, i.e., they apply everywhere and everywhen; and that certain elements of logic and mathematics are the foundations of the universe.

Topics in Early Greek Philosophy: The Presocratics Explore New Disciplines

Before Siddhartha formulated his thoughts in India, and before Confucius in China, the first philosophers lived and worked in Greek territories and colonies. Thales, who is reasonably cited as the world’s first philosopher, did his work around 600 B.C.

What constitutes philosophy? What was it that the Greeks did to qualify as the inventors of philosophy? Donald Palmer writes that “early Greek philosophers reframed the perennial puzzles about reality in such a way as to emphasize the workings of nature rather than the” dramatic explanatory power of a narrative. In other words, the Greek found a new way to explain things. In addition to myth, the Greeks began to formulate conceptual explanations.

Mythical explanations are narratives; in this sense of ‘myth,’ it’s important to remember that there are “true myths.” This is in contrast to the colloquial or informal use of ‘myth’ as a synonym for ‘falsehood.’

So the birth of philosophy among Greeks is, in part, about the “how” of explanations — aside from whether those explanations are true or accurate.

Not only did the Greeks arguably invent philosophy, they also created many of the various subtopics within philosophy. Donald Palmer identifies some of these specific subdisciplines:

This new direction represents the beginnings of a way of thinking that the Greeks would soon call “philosophy” — the love of wisdom. We can discern in these early efforts what we now take to be the main fields of the discipline that we too call philosophy: ontology (theory of being); epistemology (theory of knowledge); axiology (theory of value), which includes ethics, or moral philosophy (theory of right behavior), and aesthetics (theory of beauty, or theory of art); and logic (theory of correct inference).

One particular subtopic, cosmology, fascinated many of the earliest philosophers, including Thales, Anaximander, and Anaximenes. Cosmology asks about the foundational principles of the universe: What constitutes the universe? What keeps the universe in existence? What are the underlying essential components of the universe?

Donald Palmer remarks about these earliest philosophers:

They tended to demote cosmogony (theories about the origins of the world) and promote cosmology (theories about the nature of the world).

In addition to getting credit for inventing philosophy, the Greeks can plausibly get credit for inventing the natural sciences. To be sure, early Babylonians, Egyptians, and Persians made some interesting astronomical observations. In order to give the Greeks the honor of inventing the natural sciences, a clear boundary between the mere collection of observational data and scientific reasoning would be necessary.

“In fact, the theories put forth in ancient Greece could be called the origins of” modern science and mathematics “with as much justification as they can be called the origins of” philosophy “even though at that early period no such distinctions could be made.” Among ancient thinkers, there was no sharp separation between philosophy and the natural sciences.

Even today, there are ambiguous areas of overlap between mathematics, philosophy, and physics.

Among the Presocratics, thinkers like Zeno of Elea are still cited today in university departments of physics and mathematics. Zeno wrestled with concepts of time, space, and infinity — and wrestled with them in a way which kept his musings relevant for 2,000 years.

Other presocratics, primarily the Milesians, worked out a relationship between density, heat, and motion — anticipating the physicist Robert Brown by two millennia. The Milesians were the philosophers who lived in or near the city of Miletus: Thales, Anaximander, and Anaximenes.

Roughly, I would say that science deals with problems that can be addressed experimentally by subsuming the observable events that puzzle us under the dominion of natural laws and by showing how these laws are related causally to those events. Philosophy, on the other hand, deals with problems that require a speculative rather than an experimental approach. Such problems often require conceptual analysis (the logical scrutiny of general ideas) rather than observation or data gathering.

Before the birth of Socrates, around 470 B.C., these earliest philosophers had invented philosophy, invented most of its subdisciplines, and laid the foundations of modern physics and modern mathematics.

Greek Beginnings: The Origin of the Word ‘Philosophy’

While debatable, it is convenient to take the Ionian philosophers on the west coast of Turkey, formerly known as Asia Minor or Anatolia, as the first philosophers. Certainly, the Greeks dominated philosophy for its first few centuries: There was little philosophical activity outside of the Greek lands, so philosophy was not only predominantly Greek during these years, but exclusively so.

So it was that the word ‘philosophy’ arose out of the Greek language. ‘Sophia’ is a Greek word for wisdom, and ‘Philo’ is a Greek word for love. Philosophy is etymologically the love of wisdom, as Donald Palmer writes:

The Greek word “Logos” is the source of the English word “logic” as well as all the “logies” in terms like “biology,” “sociology,” and “psychology,” where “logos” means the theory, or study, or rationalization of something. “Logos” also means “word” in Greek.

Reasoning is impossible without words. “Logos” can mean “word,” but it can also mean reasoning or any ongoing interactive linguistic activity, “so it involves the act of” writing, “or setting forth an idea in a clear manner.” Philosophy is impossible without language, and without writing, only simplistic reasoning is possible. Complex trains of thought require writing.

But there are complications to this simple story about how the word ‘philosophy’ came to be. The Greek language has at least four words that can be translated into English as ‘love.’ Why was ‘philo’ chosen, instead of another similar word? The Greek language reflected the awareness that there are different types of love. A person might love ice cream, and parents love their children. The same word ‘love’ is used to refer to two different relationships.

Likewise, the word ‘gnosis,’ from which the English word ‘cognition’ arises, could have been used instead of ‘sophia.’

So the simple story about the origins of the word ‘philosophy’ is not so simple after all.

“Logos,” therefore, designates a certain kind of thinking about the world, a kind of logical analysis that places things in the context of reason and explains them with the pure force of thought. Such an intellectual exercise was supposed to lead to wisdom (Sophia) and those who dedicated themselves to Logos were thought of as lovers of wisdom (love = philo), hence as philosophers.

Greek philosophy began around 600 B.C., plus or minus a decade, and Greek philosophers were active until sometime after 100 A.D. There were quiet periods during those centuries when philosophy was inactive, and other periods when it was prolific.

It was in this context that the word “Logos” was applied to Jesus, and to the Hebrew concept of God which Jesus made accessible to larger audiences.

“What was there before philosophy, before Logos? There was Mythos — a certain way of” explaining things by means of narrative, i.e., by telling a story. Used in this way, the word ‘myth’ doesn’t necessarily mean falsehood. Contrary to everyday usage of the word, in philosophy, one can speak of a true myth. Myths tell of “events that caused the world to be as it is now.”

It’s understandable that philosophers would like to get rid of false myths. People like to think that they’re correct, and that what they believe is true.

But if some myths are true, why would philosophers still want to investigate the matter and find another, Logos-based, explanation?

Philosophy was, in part, a drive to develop concept-based explanations, which not only explained why things are the way they are, but explained it in a way which used reason instead of narrative, which used abstractions instead of concrete details.

In some situations, it is possible for myth-based and logos-based explanations to coexist. A true myth can give a specific and historical narrative to explain a certain state of affairs, while philosophy can explain the same state of affairs conceptually.

What Existentialism Might Be: From Kierkegaard to Sartre

The word ‘existentialism’ appears often in writings of the twentieth and twenty-first century. The frequency of its use is one of several reasons for its ambiguity. The word began to be used regularly in the 1920s and 1930s, and its appearances multiplied even more in the postwar decades.

While each author who uses the word seems to be confident about what it means, the kaleidoscope of usages does not allow for a clear meaning. A near-infinite collection of quotations about which authors are, or are not, existentialists would yield a mass of contradictions.

Alasdair MacIntyre writes:

Existentialism is not easily definable. Its protagonists have traced it back to Pascal, to St. Augustine, even to Socrates. It has been alleged in our time to be the doctrine of writers as various as Miguel de Unamuno and Norman Mailer. At first sight, characteristics of the doctrine are almost as various. That two writers both claim to be existentialists does not seem to entail their agreement on any one cardinal point. Consequently, to define existentialism by means of a set of philosophical formulas could be very misleading. Any formula sufficiently broad to embrace all the major existentialist tendencies would necessarily be so general and so vague as to be vacuous, for if we refer to a common emphasis upon, for example, the concreteness of individual human existence, we shall discover that in the case of different philosophers this emphasis is placed in contexts so dissimilar that it is put to quite different and incompatible uses. How then is existentialism to be defined?

Yet MacIntyre bravely ventures forth to attempt some semblance of a definition. Voluntarism is a common theme among those who are frequently labeled as existentialists.

If any single thesis could be said to constitute the doctrine of existentialism, it would be that the possibility of choice is the central fact of human nature. Even the thesis that existence precedes essence often means no more than that people do not have fixed natures that limit or determine their choices, but rather it is their choices that bring whatever nature they have into being. As existentialists develop this thesis, they are involved in at least three separate contentions.

The theme of voluntarism runs through, and loosely connects, the writings of thinkers like Kierkegaard, Dostoyevsky, Ibsen, and Dickens. In each, individuals are seen as making choices, or exhorted to make choices, with the awareness that the choices of individuals are significant.

This aspect of existentialism can perhaps be highlighted by contrasting it with those thinkers who oppose it. In the writings of Marx, Freud, Darwin, and sometimes Nietzsche, there is a certain mechanism or determinism which either denies choice to the individual, or minimizes its significance.

Maybe one could attempt to define existentialism by what it opposes. Marx argues that the individual human is the passive object which the grand forces of history and economics toss about like a cork on the ocean’s waves. Freud hypothesized that an individual’s thoughts and emotions were determined by experiences. Darwin constructed a system which saw choices as issuing from being who is the product of the impersonal forces of chemistry and physics.

Existentialism could be seen as a response to, or reaction against, Marx, Freund, Darwin, and similar thinkers. On the other hand, Kierkegaard, often cited as the father of existentialism, largely predated them.

By contrast, the existentialists would argue that human beings make numerous choices. Even when these choices seem to be dictated by a relatively rigid value system, that value system itself was chosen by the individual. These choices are not determined in any calculable way; therefore, any analogy to chemistry or physics is rejected.

This emphasis on choice is accompanied by a fondness, among at least some existentialist writers, for the words “free” and “freedom.”

Alasdair MacIntyre explains:

The first is that choice is ubiquitous. All my actions imply choices. Even when I do not choose explicitly, as I may not do in the majority of cases, my action bears witness to an implicit choice. The second contention is that although in many of my actions my choices are governed by criteria, the criteria which I employ are themselves chosen, and there are no rational grounds for such choices. The third is that no causal explanation of my actions can be given.

These partial hints about what existentialism might be, or about how the word ‘existentialism’ might be defined, notwithstanding, it remains difficult to answer questions like “Is Martin Heidegger an existentialist?” or “What does existentialism say about the afterlife?”

Existentialism is a construct, not a primary source. As such, it is of secondard concern relative to the actual texts of individual thinkers. Jean-Paul Sartre once famously remarked, “Existentialism? I don't know what that is. My philosophy is a philosophy of existence.”

The best and wisest route for scholarship is to treat each thinker as an individual, and to examine each thinker by means of the close reading of that philosopher’s texts.

Logical Positivism: The Influential if Unloved Innovations of the Vienna Circle

During the first half of the twentieth century, several major philosophical trends shaped the era’s significant thought. One of those movements is known by at least three names: Logical Positivism, Logical Empiricism, the Vienna Circle. These three names are almost synonymous, with only slight differences between them.

The Vienna Circle was a group of philosophers and other thinkers who met on a regular basis, discussing and publishing, in the city of Vienna during the 1920s and 1930s. While Vienna was the location of the earliest and most influential developments within this movement, Berlin and other cities were also important locations for the development of Logical Empiricism.

Movements are by nature ambiguous at their boundaries, and Logical Positivism is no exception. It is impossible to identify precise starting and ending points in time for this movement. It is not always clear which philosophers were part of the movement, and which ones were merely similar to, or associated with, the movement. Despite this vagueness, and despite the fact that movements are always constructs and not specific data points, it is nonetheless meaningful and useful to speak of Logical Positivism.

What is Logical Positivism? A definition or description of the movement would include these points: It is heavily empirical; it is anti-metaphysical; it takes physics and mathematics as paradigmatic for knowledge; it seeks to clarify philosophical questions by analysis of the words and propositions used to formulate those questions; its understanding of language is encapsulated in the slogan “The meaning of a word or sentence is the method of its verification.”

Each point in that definition requires considerable expansion.

Writing in 1969, Herbert Feigl explains:

Logical positivism began to form a fairly definite outlook in philosophy about forty years ago. As is well known, it was primarily the influence of Ludwig Wittgenstein and Rudolf Carnap that initiated the early phase of this — then new and radical — departure from the traditional ways of philosophizing. To be sure, some aspects of logical positivism are derived historically from Hume and Comte; but, in contrast, especially to Mill’s positivism, a new conception of logic (having its origins in Leibniz, Frege, and Russell) was united with the empiricism of Hume, Mach, and the early Einstein.

When Logical Positivism is described as heavily empirical, it means that the movement took observation to be the foundation of most knowledge.

As an anti-metaphysical movement, it considered words and sentences which refer to nonobservable things to be not wrong, but nonsensical. Thus the movement would consider a discussion of the mind, as separate from the brain, to be nonsense.

Because it takes physics and mathematics as paradigmatic for knowledge, it tends to favor what is quantifiable and measurable in observation. It looks to mathematics, and mathematical logic, to provide a framework in which observations can be organized.

The group sought to resolve philosophical paradoxes — longstanding questions, riddles, mysteries — by analyzing the words and sentences which formulated them. The Logical Positivists thought that many problems which had puzzled philosophers for years were the result of poorly-phrased propositions.

The method by which the Logical Positivists hoped to clear up philosophical misunderstandings — or what they took to be misunderstandings — was called “verificationism.” This method looked at a sentence — a proposition — and asked: by which procedure would it be determined whether this sentence is true or false? If such a method were found, then the Logical Positivists asserted that the method is the meaning: The meaning of a sentence is the method of its verification.

Herbert Feigl was a member of the Vienna Circle, and recalls:

The Vienna Circle consisted mainly of scientifically trained philosophers and philosophically interested mathematicians and scientists. Most of the members were tough-minded thinkers, Weltzugewandt (as Hans Hahn put it), ‘this-worldly’ rather than ‘other-worldly.’ They were radically opposed to metaphysical speculation, especially of the a priori and transcendent types. Since the development of the Vienna Circle is by now a familiar chapter in the history of recent philosophy, I propose, after dealing with some of the antimetaphysical doctrines of logical positivism, to concentrate on some of the aspects that are not as well known. I shall refer particularly to the work of Moritz Schlick, the founder and leader of the Vienna Circle. Schlick’s early work anticipated a good deal of what in more precise formulations was later developed by Carnap, Reichenbach, and others. In his Allgemeine Erkenntnislehre (first edition, 1918; second edition, 1925) there were also anticipations of some of the central tenets of Wittgenstein’s Tractatus Logico-Philosophicus. I think it was Schlick’s extremely unassuming character, his great modesty and kindliness, and his deep personal devotion to Wittgenstein that made him forget or suppress the great extent to which his views, independently developed and quite differently stated, already contained very important arguments and conclusions regarding the nature of logical and analytic validity; the semantic explication of the concept of truth; the difference between pure experience (Erleben), acquaintance (Kennen), and genuine knowledge (Erkennen), etc. Indeed, so deeply impressed was Schlick with Wittgenstein’s genius that he attributed to him profound philosophical insights which he had formulated much more lucidly long before he succumbed to Wittgenstein’s almost hypnotic spell.

The methods and assertions of Logical Positivism arose, in part, as reactions against some overly metaphysical trends among other groups of philosophers, like the British Idealists and other neo-Hegelian and post-Hegelian schools of thought. Logical Positivism may have served as a corrective and as a challenge to such idealism.

While there was value in not letting idealism go uninspected, it is also the case that, after the movement’s heyday in the late 1930s, there are few self-proclaimed Logical Positivists among the philosophers of the early twenty-first century.