Logical positivism

Copyright 2016 Graham Berrisford. One of about 300 papers at http://avancier.website. Last updated 17/03/2019 13:32


For more discussion of ideas and issues raised here read papers under “Systems science and philosophy” on this system theory page https://bit.ly/2yXGImr


Logical positivist philosophers focus on analysing the meaning of language used in philosophical propositions.

People use the words and grammar of a language to describe things.

The fluidity and imprecision of natural language enables human creativity and assists survival in a changing world.

The position in these papers is studying natural language is not a good basis for a science or philosophy of systems.

To specify a system in an unambiguous and testable way, an artificial domain-specific language is needed.


Wittgenstein. 1

Wittgenstein 1: His seven propositions. 1

Wittgenstein 2: Family resemblances and natural languages. 3

A different Tractaco. 4

The logical syntax of language. 5

Conclusions and remarks. 6




Ludwig Wittgenstein (1889-1951) influenced the “Vienna circle” of logical empiricists (aka logical positivists).

He argued philosophical disagreements and confusions can be resolved by analysing the use and abuse of language.

In his “Tractatus Logico-Philosophicus” he set out seven propositions.

The propositions are famous for being a tough read, and have been interpreted in various ways.

Eventually, Wittgenstein realised his “Tractatus” was self-contradictory, and developed an entirely different linguistics.

Wittgenstein 1: His seven propositions

 I gather the premises are as follows.

·         Philosophical propositions have logical structures.

·         Many propositions are poorly formulated; and futile debates arise from misunderstandings.

·         Philosophical disagreements and confusions can be resolved by analysing the use and abuse of language.


Proposition 1) The world is all that is the case

Wittgenstein’s first proposition includes these statements.

1 The world is all that is the case.

1.1 The world is the totality of facts, not of things.
1.2 The world divides into facts.


I understand this to say: the world is the totality of facts, and language is the totality of propositions.

The world and language are structured the same way.

Philosophy should confine itself to facts set out in well-structured propositions.


Here, we challenge the view that "facts" are the only reality.

The world is mysterious, unknowable as it is.

There are infinite ways to describe the world in terms of facts that are true enough.

Any description that helps us to predict or direct how the world moves forward must be a reasonable model of that world.

The better and more completely we can predict and direct reality, the closer our model to that reality.


Proposition 2) What is the case, the fact, is the existence of atomic facts

Wittgenstein’s second proposition includes a discussion of objects, form and substance.

2.02 Objects are simple.
2.021 Objects make up the substance of the world. That is why they cannot
be composite.


Here, we say our perceptions and descriptions of reality divide it into discrete chunks.

We can divide the universe in infinite ways - into stars, planets, the eyes in a peacock’s tail, the verses of a song.

With the exception of atomic physicists, people always perceive and describe composite objects and events.

What we regard as atomic differs according to the context.

What we regard as an atomic entity differs according to the context.

What we regard as an atomic event differs according to the context.


Wittgenstein goes on to say:

2.0271 Objects are what is unalterable and substantial; their configuration is what is changing and unstable.

Here, we say "facts" are atoms of description rather than atoms of reality.

All real objects are alterable, and they have a limited life time.

Every object is created, it may change during its existence, and it will be destroyed in the end.


Proposition 3) The logical picture of the facts is the thought

Does this confuse static facts with dynamic thinking?

Here, we say a thought is a process that involves creating and using logical models.

Thinking abstracts logical models from other logical models and from physical bio-electro-chemical models.


On meeting somebody we start thinking “What is that person’s name?”

That thought process explores our physical brain and might end in our expressing a logical “fact” -  a name, right or wrong.

Or it might continue unsuccessfully, eventually fizzling out when other thoughts occupy our thinking resources.


Proposition 4) The thought is the significant proposition

Proposition 4.003 says:

“Most of the propositions and questions of philosophers arise from our failure to understand the logic of our language.”

Later: In Philosophical Investigations Sect. 90 Wittgenstein said this.

“Our investigation is a grammatical one. Such an investigation sheds light on our problem by clearing misunderstandings away.

Misunderstandings concerning the use of words, caused, among other things, by certain analogies between the forms of expression in different regions of language.”


Here, we say our language is naturally messy and imprecise.

That almost all our thoughts and propositions are fuzzy rather than true or false.

Most if not all our propositions can be true or false only with reference to others within a limited descriptive ontology.


Proposition 5) Propositions are truth-functions of elementary propositions

Ditto. Here, we say our language is naturally messy and imprecise.


Proposition 6) The general form of a truth-function or proposition is…

Ditto. Here, we say our language is naturally messy and imprecise.


Proposition 7) Whereof one cannot speak, thereof one must be silent

Here, we say people are well advised to ignore this rule, because natural language is not reducible to true or false sentences.

So, we need feedback to refine our thoughts and our speech.

We say what is in our minds, partly to open our thoughts to inspection and correction - by ourselves and others who listen to us.

Wittgenstein 2: Family resemblances and natural languages

Eventually, Wittgenstein realised his “Tractatus” was self-contradictory, and developed an entirely different linguistics.

In “Philosophical Investigations”, published after his death, he developed an entirely different linguistics

He dropped the metaphor of language “picturing” reality and replaced it with language as a tool.

He turned his focus from the precision of language to the fluidity of language.


To describe something as the game is to suggest it is the only one of that named type.

To describe something as a game is to suggest it is one of a set containing many things of that named type.

Wittgenstein considered games as a set, and “game” as a type name.

The set includes activities as varied as chess, archery and Super Mario.

He argued the set members have overlapping lists of features, but no single feature in common.

Thus, Wittgenstein used “game” as an example to tell us that words are not type names.

Rather, games exhibit family resemblances.


This is disappointing if you are a mathematician who had hoped that a word naturally defines the members of a set.

But it is no surprise to a biologist or psychologist coming at this from a different direction.

Natural language is a biological phenomenon rather than a mathematical one.

We use words to indicate one thing resemble another in a loose and informal way.

No word, description or message has a universally-agreed meaning.

Since the words and grammar we use are so flexible, there is ambiguity and fuzziness in natural language

And degrees of truth in how well a reality matches a description we make of it.


The marvel is not that words are used so loosely in natural language.

The marvel is that we can force them to act as the names of types that do have one or more features in common.

E.g. A biologist might define a game as “an activity that serves as a direct or indirect rehearsal of skills useful to survival.”

For science, and to create a holistic, unambiguous and testable description of a system, we must do this.

We have to create an artificial domain-specific language in which words act as type names.

A different Tractaco

There was no description of reality before life.

Description is a side effect of biological evolution.

Descriptions appear mental phenomena and in external representations of them in speech, writing and models of various kinds.


Many more or less accurate copies of a description can be made.

There is no ethereal description aside from what exists in one or more copies of it.

Delete all copies of a description and it disappears from the universe.


Descriptions are created when actors encode them in some form of matter and/or energy.

Descriptions are used when actors decode them from those forms.

Communication between actors succeeds when the encoded and decoded meanings are the same.


With those assertions in mind, here is a short Tractaco Logico Philosophicus - different from Wittgenstein’s.

A new Tractacus Logico Philosophicus

In so far as philosophy is about language, knowledge and truth, it seems to have been overtaken by biological and software sciences.

This new attempt at a “tractacus” is written from the perspective of a psycho-biologist rather than a linguist or mathematician.


-1- Reality is what exists in matter and energy, in space and time.

The context is the universe we live in, as observed and described by physicists.

Whether the same system theory would apply in alternative universes is out of scope here.


-2- A description is created by an actor (internally or externally) to represent a reality that is observed or envisaged.

A description is a representation of a reality – real or imagined.

Other kinds of information (directions and decisions) are mostly out of scope here.


-3- A description is also a part of reality

Description is not an ethereal concept.


-4- There are degree of truth in description creation and use, which makes them subjective.

The words “true” and “false” may be read as “true enough” and “false enough”.

Because truth and falsehood are judgements made by description creators and users at a moment in time.

And those judgements may be different on different occasions.


E.g. “Standing on that railway track is dangerous” may be judged as:

·         True to an actor who creates the description with the intent to represent a reality - well enough to be useful.

·         True to an actor who finds (in empirical or logical tests) that it does represent a reality - well enough to be useful.


E.g. “This horse has five legs” may be judged as:

·         False to an actor who creates the description with the intent to misrepresent a reality.

·         False to an actor who finds (in empirical or logical tests) that it does misrepresent a reality.


-5- A description (e.g. of a unicorn) is fanciful to an actor who believes it represents an imaginary reality

However, it might later turn out to true.


-6- Communication succeeds when the meanings/information in a description are the same when encoded and decoded - near enough.

Communication is a process that conveys a description (and/or other information) from a creator to a user.

The description and communication processes are performed by actors that may be animals or machines.

“Thinking” and “intelligence” includes the ability to create and use descriptions, and more that is out of scope here.


-7- Communication requires that speakers and listeners share the same language for encoding and decoding a description.

A language contains a set of symbols used in the process of creating and using descriptions.

Mostly, we are talking about languages with verbal or graphical symbols, but symbols can also be gestures or even smells.


-8- To share a language, human speakers and listeners must share a lot more.

They largely share same biology, psychology, experience of the world and education.

-9- A description typifies what is described; it attributes general properties or qualities to particular things.

Every description could, potentially, be realised in several realities.


-10- Natural language types are loose, fuzzy and flexible (as Wittgenstein observed).

However, the process of forming a system description involves formalising descriptive types - as follows.


-11- A description may be a singular type (e.g. tasty) or a compound type (hot, tasty, liquid).

A system description, however large and complex, can be seen as a compound type.


-12- A singular description/type is explained in a circular fashion in terms of other descriptive types.

E.g. A “rock” might be described/typified as “dry”, “perceptibly discrete entity”, “solid body” and “mineral material”.


-13- To create a consistent and coherent domain-specific language we must break the circularity by agreeing some basic axioms or base types.

To describe a system, we must create a domain-specific language.


-14- In languages for describing systems, the base types divide along the lines of space and time.

System describers typically perceive and describe systems in terms of

·         actors (cf. objects) that occupy space at a moment in time and

·         activities (cf. motions) that occur over time..


Nothing said above depends on human language or linguistics.

However, the ability to form descriptions using words (and graphical symbols of them) dramatically extended human descriptive/typification ability.

The logical syntax of language

Rudolf Carnap (1891 – 1970) was a member the Vienna circle who contributed to the philosophy of science and of language.

Carnap has been called a logical positivist, but he disagreed with Wittgenstein.

He considered philosophy must be committed to the primacy of science and logic, rather than verbal language.


Carnap’s first major work, Logical Syntax of Language can be regarded as a response to Wittgenstein 's Tractatus.

the sentences of metaphysics are pseudo-sentences which on logical analysis are proved to be either empty phrases or phrases which violate the rules of syntax.

Of the so-called philosophical problems, the only questions which have any meaning are those of the logic of science.

To share this view is to substitute logical syntax for philosophy.”

— Carnap, Page 8, Logical Syntax of Language, quoted in Wikipedia.


He defined the purpose of logical syntax thus:

to provide a system of concepts, a language, by the help of which the results of logical analysis will be exactly formulable.”

“Philosophy is to be replaced by the logic of science – that is to say, by the logical analysis of the concepts and sentences of the sciences...”

Foreword, Logical Syntax of Language, quoted in Wikipedia.


He defined the logical syntax of a language thus:

the systematic statement of the formal rules which govern [the language] together with the development of the consequences which follow from these rules.

Page 1, Logical Syntax of Language, quoted in Wikipedia.


Carnap’s second major work, Pseudoproblems in Philosophy asserted that many metaphysical philosophical questions were meaningless.

His Principle of Tolerance says there is no such thing as a "true" or "correct" logic or language.

His concept of logical syntax is important in formalising the storage and communication of information/descriptions.

Computers require that logical data structures are defined using a formal grammar called a regular expression.

It is said that Carnap’s ideas helped the development of natural language processing and compiler design.


As I understand it, Carnap said:

A statement is only meaningful with respect to a given theory - a set of inter-related domain-specific predicate statements.

And only true to the extent it can be supported by experience or testing.

Conclusions and remarks

Here, we do not regard natural language as the basis for a philosophy of system theory.

Friedrich Nietzsche (1844 to 1900) was a philosopher whose metaphysical ideas influenced many Western intellectuals.

He took the view, called “perspectivism”, that our conceptualisations of the world are shaped by how we view it.


“Against positivism (the position ‘There are only facts’) I would say: no, there are precisely no facts, only interpretations.

To the extent that the word ‘knowledge’ has any sense, the world is knowable: but it is interpretable differently, it has… innumerable senses, ‘perspectivism.’

It is our needs that interpret the world: our drives and their to and fro.” Nietzsch


Some postmodernists read Nietzsch as saying there is no objective truth or accurate knowledge of the world.

Some interpret his assertion as meaning all descriptions of the world are equally valid.

Any appealing belief or poetic assertion carries the same weight as scientific evidence.


To some extent, different people do perceive the world differently from each other, and from birds, bats and bees.

But more importantly, their conceptualisations are shaped by testing them against reality.

All animal life depends on two facts: a) there is a real world, and b) only some descriptions of reality prove accurate enough when tested.


Here: natural language is a biological phenomenon, a product of evolution that gives us tools we need to communicate.

But it is imprecise, ambiguous and fluid.

The role of words in biology is to help us to remember and communicate descriptions that are true enough.

Words didn’t evolve to enable us to formulate perfectly true propositions (a concern of philosophers and mathematicians) they are not good for that.

Usually, any "state of matters" or "fact" that one animal recalls or communicates to another is a perception that has "degrees of truth".

Newton’s laws describe the motion of things in the reality we normally experience.

The laws are true to the degree of accuracy we need, but only approximations, neither wholly true nor wholly false.


For more discussion of ideas and issues raised here read papers under “Systems science and philosophy” on this system theory page https://bit.ly/2yXGImr



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