Logical empiricism

Logical empiricism, also called neopositivism or logical positivism, is a current in the philosophy of science that limits the validity of the scientific method empirical and verifiable. This limitation, known as verificationism, prohibits inducing a general rule from particular observations, which eventually aroused criticism about the incompatibility of this current with many branches of science based on induction to build valid knowledge. Logical empiricism or neopositivism is even stricter than positivism and its defense of the scientific method as the only valid form of knowledge.

Logical empiricism arose during the first third of the 20th century around the group of scientists and philosophers who formed the famous Circle from Vienna.

Logical empiricism and verificationism

Although logical empiricists tried to offer a vision of science that mainly encompasses its epistemological and methodological aspects, perhaps their best-known thesis is verificationism, which maintains that a statement is cognitively significant only if it has a method of verification. empirical verification (empiricism) or is analytical (logicism). Only statements from empirical science meet the first requirement, and only statements from logic and mathematics meet the second. Typically philosophical or theological statements do not meet either of the two requirements, so philosophy, as such, must go from being a supposed body of propositions to a method of logical analysis of the statements of science.

With the progress of science, the study of fields that are beyond experience began, such as high energy physics or atomic physics. In this situation, the empiricist criterion of truth led to many problems, which led to various nuances of it. Strict verificationism ended up being abandoned and replaced by the contrast between propositions and observations, which allows a gradually increasing confirmation of theories.

The assertion introduced by empiricism that there are pure data (without any kind of interpretation or elaboration) and the positivist assertion that science should use an observational language devoid of theory are especially criticized by scholars. major philosophers of science for decades and, today, strict neopositivism is no longer considered viable. However, in his day he held sway in the philosophy of science. His influence has been capital and is traceable in many philosophers today. The positions of logical empiricists regarding some key issues in the philosophy of science (the origin of the meaning of statements, the testing of theories, the concept of scientific explanation and the unity of science, among others) are known by the collective name of "inherited view" (received view).

Empiricism and logicism are the two main sources of the origins of analytic philosophy, and logical empiricism was one of the first strong movements within analytic philosophy. Within it also has a special place the study of logic and language.

Vienna Circle

It is usually considered that the philosophy of science reached its adulthood in the 1920s with the appearance of the Vienna Circle, which included a large group of philosophers such as Rudolf Carnap (1891-1970), Otto Neurath (1881-1945), Hans Hahn (1879-1934), Kurt Gödel (1906-1978), Willard V. Quine (1908-2000). In imitation of the one in Vienna, Hans Reichenbach (1891-1953) founded the Berlin Group or Circle.

The original group that constituted the Circle was a group of scientists and philosophers started in 1924 by Moritz Schlick; later, Rudolf Carnap would be the follower and leader.^{[citation required]} Most of the components of the Vienna Circle emigrated to other countries from 1933, as a result of the coming to power of Nazism.

As antecedents, personalities such as Locke and Hume were mentioned in the Vienna Circle Manifesto, while others such as Karl Marx (for his scientific treatment of history), Leibniz (for his mathematics and logic) were also considered precursors, but without counting on its metaphysics. The positivism of the XIX century is also considered an influence, although with nuances. It must be remembered that, for the positivists of the XIX century, «only what is given is real».^{[citation needed]} To logical empiricists, this proposition is simply meaningless.^{[citation needed]}

Other powerful influences were the empirical methodology developed during and after the mid-XIX century, as well as symbolic logic. Among the developers of the first, there are scientists like Helmholtz, Ernst Mach, Henri Poincaré, Pierre Duhem and Boltzmann. Among the developers of the second are, among others, Frege, Russell, Whitehead, Giuseppe Peano and Tarski.

The Circle of Vienna included, among others: Rudolf Carnap (1891-1970), who proclaimed the overcoming of metaphysics through the logical analysis of language (see The overcoming of metaphysics through the logical analysis of language language); Kurt Gödel (1906-1978) who never came to share the positivist theses of the Circle, as he would finally demonstrate when formulating his famous incompleteness theorem, incompatible with certain theses of the philosophy of mathematics held by some of they; David Hilbert (1862-1943) the famous editor of The Future Problems of Mathematics; and others such as Herbert Feigl, Philipp Frank, Hans Hahn, Carl Gustav Hempel, Karl Menger, Richard Von Mises, Otto Neurath, Hans Reichenbach, Moritz Schlick, and Friedrich Waismann. In England, Sir Alfred Jules Ayer (1910-1989) was the most important representative of this current (see Language, truth and logic )

Dr. Craidoff proposed a model of science in which science proceeds by generalizations (induction) from data. Dr. Craidoff's central idea is that science should use theories as tools to predict observable phenomena and should give up seeking explanations. The search for explanations is a function of metaphysics, a discipline that, according to the verifiability criterion of positivism, would be devoid of meaning. Thus, neopositivism presents an instrumentalist vision of science.

A priori, a posteriori, analytical and synthetic

In the Critique of Pure Reason, Immanuel Kant proposed that statements are of two kinds: analytic and synthetic. The difference between these two statements lies in the way in which truth is preached to them: for the analytics, only according to the meaning of their terms; for synthetics, depending on how the world is. The analytics, then, tell us nothing about the world: they are pure tautologies. Synthetics do talk about the world. Examples of analytic statements: "All bachelors are unmarried"; "the color black is dark." Examples of synthetic statements: "there is a car out there" or "it is raining".

Now, there is also a difference between how statements are known: some are knowable a priori and others a posteriori. The a priori are knowable by a pure exercise of reason, without the need to resort to the world. The a posteriori need, in order to be known, that the subject resort to the world.

What is a priori is necessary (it cannot not happen) and what is a posteriori is contingent (it can not happen).

Kant had said that there are some synthetic statements a priori, that is, some statements that tell us things about the world and that can be known without resorting to empirical observation; and that, since they are a priori, then they are necessary. For Kant, a synthetic a priori would be mathematics, or the metaphysics of customs.

Logical empiricists accept Kant's distinctions, but deny that there can be a synthetic a priori: if there is, then there are statements that talk about the world but do not need empirical verification. But empiricists want to get away from this path. The next section will explain why.

The sense of a proposition, pseudo-propositions and pseudo-problems

How do we know that a statement like "It's raining today" is true? We hear the rain, or see the water fall and smell the wet earth: so we know that today, in fact, it is raining. So the statement "Today it is raining" it makes sense, because we can tell if it is true or false. Now, how do we know that a statement like "Being is immobile" it's true? Obviously we have never seen such a thing as "the Self", nor have we seen it move, stand still, or smile. So how do we know if that statement is true? The metaphysicians would have responded: of course not through empirical evidence, since that kind of evidence has not led us to talk about Being. They are statements that are demonstrated by pure reason, a priori. But remember that logical empiricists have denied that we can talk about the world -synthetic statements- without experience of it -a priori-.

Logical empiricists say: we can only talk about what the world is like if we have sensory experience of it. If we talk about the world, it is because we perceive it through our senses. Is there any other way to know the world, besides the senses? Yes, through logical-deductive reasoning, that is, the a priori, such as mathematics, logic and conceptual meanings.

The sense of a proposition is determined, early Wittgenstein, Russell, and the logical empiricists believed, by sensory experiences that can tell us whether that proposition is true or false. If there are no sensory experiences that can tell us if "The Being is immobile" is true or false, then "The Being is immobile" Meaningless.

It can be argued that 'Being is immobile' it is a completely well-structured statement, grammatically speaking; but the logical empiricists establish that only those that are the product of logic, of mathematics or that can be empirically verified can be qualified as propositions -or, for Popper, susceptible to falsification. Every other sentence is a pseudo-proposition.

Sentences like "Being is immobile" or "the Nothing swims" seem to be well structured in a subject-predicate form: "the Being" and "the Nothing" would be the subjects of the two sentences; "is motionless" and "nadea" their respective predicates. However, 'Being' and 'Nothing' they are not subjects: one is a verb and the other is a quantifier. We commit the fallacy of reification by believing that they are subjects. In other pseudo-propositions such as 'God possesses infinite attributes' or & # 39; I have free will & # 39;, the problem is that there is no way to verify this empirically: no one can see God and recognize him in his infinite attributes.

The problems of metaphysics, then, say the logical empiricists, are pseudo-problems: they cannot be solved, but must be dissolved by an analysis of language, with the help of logic. Such an analysis will prove to us that we were not referring to matters of fact, but that we were misusing language. This misuse is called by Carnap "pseudo-object language", because it seems to refer to objects or events in the world, but it is not. The "object-language" real is the language of science, as propositions like "The Moon is round" or "Water is H2O", which do refer to the world.

For this very reason, metaphysics would be wiped off the map simply by analyzing and finding the errors that lay in it. Something very similar would happen with ethics and aesthetics. Ethics would leave philosophy because statements like "hate is bad" They are not really declarative statements -they do not talk about matters of fact-, but imperatives: they say something that must be done. However, these imperatives commit the naturalistic fallacy by deriving what must be the case from what in fact is the case. For this reason, ethics would move from philosophy to the field of psychology, which would tell us why we actually believe that certain things are good and others are bad. The same, with appropriate substitutions, would happen with aesthetics. The metaphysical elements of the two subjects would, of course, be eliminated.

Reductionism, protocol statements, foundations of knowledge and epistemology

Then: the sense of a proposition is determined empirically. If this is so, then for every meaningful proposition in physical-language (such as "The Moon is round"), there is a corresponding proposition in sensory-language. (A proposition in sensory language is one that immediately reports the data received by the five human senses, adding quantifiers, connectives, and spatiotemporal coordinates to make it meaningful: "There is a soft and acid red here, at this moment"; or: "at 7 in the morning on Thursday, I saw a round white in such and such a place").

That is, the sentence "The Moon is round" can be reduced to statements like "There is a round white object at this moment such that we call it Moon". Carnap and some others, like Schlick, believed that these statements were the foundation of our knowledge. They called these utterances in the sense-language protocol utterances. That is, to find out if we were justified in saying that we know this or that proposition, we must appeal to these statements (remember that the meaning of a proposition is its empirical verification conditions).

For another member of the Vienna Circle, Otto Neurath, the foundation of knowledge is not these propositions, and in fact knowledge has no foundation: knowledge occurs only between coherent systems of propositions, and justification is not asymmetric (that is, there is no more justification in one proposition than in another), but is mutually granted between propositions. Moritz Schlick debated with him and, in fact, this very debate would last - even though logical empiricism had already been rejected - at the center of epistemology for almost the entire century XX: the foundationalism/coherentism debate.

A priori

There are 2 ways in which a proposition can make sense: by talking about the world and therefore having well-determined empirical verification conditions, or by not talking about the world. We have seen that statements about the -synthetic- world, for logical empiricists, could only be a posteriori, that is, only empirically verifiable. But there is also another way of knowing something: a priori.

I know that 2×2 is 4, always, and I don't have -although I can do it, of course- to count on my fingers or lock myself in the laboratory to find out: I only know by calculating. In the same way, I know that no bachelor is married, and without resorting to an experiment. I also know that, by modus ponens, I can deduce the proposition 'and' given two premises: if 'x', then 'y', and it is the case that 'x'. For this he did not need any experimentation either, he did not need to resort to the world. I know this a priori, without experience. But, since I know it without experience, then neither the modus ponens, nor the multiplication of 2 by 2, nor the singleness of the unmarried tell me anything about the world. How were they going to do it, if I can know them without empirical experiences? And since they tell me nothing about the world, then they are analytic propositions, which are true only by virtue of the meaning, and of the stipulated rules. "Every single is unmarried" is true because being single means not being married. 2×2=4 is true because of the stipulated uses we give to the signs '×' and ' = ', in addition to the rules we follow when giving them that use, and the meanings we give to signs 2 and 4. [(P-->Q)&P]-->Q is true also because that is how our language works, and because that is how we have said that the signs & and --> and the metavariables P and Q.

For this reason, all truths a priori are, for logical empiricists, analytical. And since they are a priori they must be necessary. Let us remember that synthetic propositions are those whose truth value depends on the facts in the world. And for this reason they are contingent: they may or may not have happened or may not have happened. I might not be writing this article (as I might be studying for the exam), you might not be reading this, it may rain today, Socrates may not have been born, the nation's president may die tomorrow.

Now, we have said that analytics are true not in terms of the world, but in terms of meaning and rules. '2–1=1' It's always going to be true, of course, as long as there are such meanings and rules. But if, in another language, 'monkey' outside what we understand by '2'; 'dog' what we for '1'; 'run' by '-'; and 'strip of subjects' by ='; then 'monkey runs dog pulls dog materials' would still be true, since the rules of the 'operation' but a change (renaming) in the variables involved.

This tells us why all statements that are analytic are a priori, and also necessarily true. When a truth table is given to a proposition or set of propositions, and it turns out that such a proposition is true in all cases, we say that this proposition is tautological. This happens with analytic propositions, and for this very reason we say that they are necessary.

For logical positivists, then (following the early Wittgenstein), all analytic statements are tautologies, that is, they are always true. (Statements that are always false are called self-contradictory.)

Unification of science

Remember that a statement in physical language can be reduced to another in sensory language: "there is a table" can be reduced to something like "in such a place and at such a time, I perceive brown color, rectangular shape...", etc. And these statements would be the basis of our knowledge.

This being so, then the empiricist project seemed possible: to reduce all of natural science to protocol statements. Carnap introduces -shortly after and facing the problems that this implied- in addition to sensory experience, logic and set theory.

Russel and Whitehead had already begun the task of reducing mathematics to logic. If we could do this reduction, the great theorems and the enormous proofs would become clearer, because we would know the fundamentals. In the same way, theories in the natural sciences would be clearer and more secure knowing what they were founded on: on what protocol statements.

And since everything was to be reduced to protocol statements, then natural science would be seen as an extensive set of such statements.

Induction and falsifiability

A huge problem that Hume inherited is basically how we justify induction (ie, loosely put, going from the particular to the general). Hume realized that it is not valid to go from what in fact is and has been the case, to what will be or should be the case, without any justification for it.

This problem calls into question all of natural science, which is based on inductive reasoning. Thus, some members of the Vienna Circle (among them Carnap and Reichenbach) tried to find a solution. Of course there was no definitive.

Karl Popper is a character closely related to the Vienna Circle, but he never confirmed himself as a positivist. However, his philosophy was very close to that of the Circle. His answer to the problem of induction is that science does not advance by confirming theories observationally, but by showing that they do not contradict experience. This is, broadly speaking, falsificationism.

Popper severely criticizes inductivism and supersedes it from the philosophy of modern science through logic and the theses of fallibilism. Furthermore, it demonstrates that scientific justificationism is incorrect because observable (empirical) statements cannot be proven, but can simply be accepted or rejected by convention according to the experimental theories, instruments and rational criteria commonly accepted at the time.

According to falsificationism, a theory will only be scientific if along with it it is stated what fact or set of facts could refute it. This is known as the demarcation criterion. The hypotheses or theories that are not falsifiable in this way will be pseudoscientific, while the falsifiable ones will be scientific and can be refuted or corroborated as experiments are carried out, which will be aimed at achieving their refutation. On the other hand, a scientific theory would be rejected if it is disproved, which is achieved through an experiment that contradicts it. This experiment is often called the crucial experiment.

Philosophy and logical analysis

Wittgenstein, in the Tractatus logico-philosophicus, had already said that the only way left to do philosophy, after eliminating metaphysics, was analysis.

All philosophy is “lingual critique”. (In any case, not in the sense of Fritz Mauthner.) Russell's merit is to have shown that the apparent form of the proposition does not have to be its actual form. The proposition is a figure of reality.

This is the proposition of logical empiricism: without metaphysics, psychology, or normative branches, what remains is logical analysis. Philosophy would be the analysis of the propositions of science, which would be purified of all nonsense and all metaphysics, and based on the theory of knowledge (epistemology).

Criticism of logical positivism

Ludwig Wittgenstein in his Philosophical Investigations, Popper in The Logic of Scientific Investigation, Quine in From a Logical Point of View and others criticized the fundamental postulates of logical empiricism. In fact, there was never a unanimous agreement within the Vienna Circle. ^{[citation required]}

Hempel (in "Problems and changes in the empiricist view of meaning") criticized Ayer's verificationism.

Popper criticized the idea of induction from the application of formal logic. According to Popper, it is invalid to extract general statements from particular statements; that is, it is logically wrong to conclude from the statement: some X behave in a Z way, the statement: all X behave in a Z way. In addition, he criticizes verificationism, since in a theory it must be possible to verify all the postulates to say that it is true, which is impossible. Rather, one should conclude that the theory is false if one of its predictions is false (Popper's falsificationism).

Among other important critics of logical positivism are Imre Lakatos who developed sophisticated Falsificationism in research programs, Thomas S. Kuhn with his relativist, historical and sociological vision of science, with the main contribution of the term Paradigm and the Scientific Revolutions and Paul Feyerabend who argues that there are no single judgment criteria and who promotes Methodological Anarchism as a more open and fruitful vision of science. In addition, he makes a commitment to other types of knowledge, outside of scientific knowledge, such as knowledge of psychoanalysis or witchcraft ^{[citation needed ]} .

Among the critics of Spanish-American origin of logical empiricism, the Argentine Mario Bunge stands out for the originality and breadth of his alternative proposal, who despite praising the power of formal philosophical analysis, distances himself from empiricism logical for his defense of a materialist ontology and for his integral realism.

Logical empiricism as not cognitively significant by its own criteria

It has been pointed out by thinkers such as the physicist David Deutsch, that logical empiricism is in immediate conflict with its own terms. This is because the phrase that defines logical positivism is the following: "a statement is cognitively significant only if it either has an empirical verification method or is analytical". Now, this statement enclosed in quotation marks would not be, according to the criteria contained in it, a cognitively significant statement, since it cannot be verified empirically (since it does not lend itself to experimental verification), nor is it analytical (since it is not a own statement of mathematical reasoning).

However, it is possible to perceive whether a statement makes sense. Can you tell which of the 3 statements makes sense?

1. "Abracadabra is a second intention."
2. "The bike is on the left of the car."
3. "An immaterial alien lives in an immaterial exoplanet."

Since the second sentence is verifiable or falsifiable, we note that it makes sense.

Positivism, analytical philosophy and metaphysics

The philosophy of logical positivism was perhaps one of the most influential during the first half of the XX century, along with the German and French continental metaphysics. Although logical positivism was rejected on its own terms, its influence endured in what is known as analytic philosophy.

However, to believe that contemporary analytical philosophy is positivist is a serious mistake.

Later, the need to formulate metaphysical/ontological and ethical theories was seen, but, to avoid nonsense, now shielded with the powerful weapon of logic.

Even today the rupture between the so-called analytical philosophy and continental philosophy (heirs of Hegel, Heidegger, etc.) survives, although there is a tendency to dismiss it and/or try to overcome it.

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