Critical Rationalism by Karl Popper and Hans Albert

Research Paper (postgraduate), 2021

24 Pages, Grade: 1.3

Simon Valentin (Author)


Table of Contents

List of Figures

1. Introduction

2. Epistemology
2.1 Rationalism
2.2 Empiricism
2.3 Positivism

3. Context for the development of Critical Rationalism
3.1 Problem of Induction
3.2 Demarcation Problem

4. Critical Rationalism as a school of thought
4.1 Cornerstones of Critical Rationalism by Karl Popper
4.1.1 Principle of falsifiability
4.1.2 Deductive reasoning and falsification
4.1.3 Truth and progress in knowledge
4.2 Contributions and advancement by Hans Albert

5. Critical Appraisal and Conclusion


List of Figures

Figure 1: School of Thought by Criterion

Figure 2: Scheme of the progress of knowledge according to Popper

“No amount of experimentation can ever prove me right; a single experiment can prove me wrong.” (Albert Einstein as cited in Calaprice, 2005, p. 291)

1. Introduction

Karl Raimund Popper was a renowned science theorist and philosopher in the 20th century (Keuth, 2013). He was born in Vienna in 1902 and died in London in 1994 (Brockhaus Philosophie, 2009). After the end of the First World War, Popper attended courses in the field of mathematics, history, theoretical physics, philosophy, and psychology. Karl Popper earned his doctorate in psychology in 1928.

Popper's most important work The Logic of Scientific Discovery presents an important concept of scientific theory (Keuth, 2013). It has established itself as an essential school of thought within epistemology and influences research methodology within empirical social science to date (Keuth, 2013).

Theories claim that they provide a complete explanation of facts without any inconsistencies and/or gaps. A theory should include the best possible justification. Epistemology and philosophy of science ensure the theoretical examination of theories, for example, their genesis, establishment, and testing (Schülein/Reitze, 2005; Seiffert, 1997). The epistemology addresses the issues of what knowledge is, how knowledge emerges, and how it operates. The theory of science as part of philosophy or subdomain of epistemology examines these questions with the special requirement of its application to science (Schülein/Reitze, 2005; Brühl, 2017). It examines epistemological (logical, methodological), action-theoretical, normative as well as ontological (metaphysical) issues of science (Dellantonio, 2010).

The main task of epistemology is to explain the logic of recognition, whereas the theory of science provides insights into the functioning of a particular form of institutionalized knowledge, including its genesis and justification (Schülein/Reitze, 2005; Brühl, 2017). Thus, according to Popper, it can be stated that science can be described as the search for truth (Popper, 1994).

Popper's philosophy addresses issues that are general in nature and independent of individual fields of science. This yields in a general methodology that can be applied to all experiential theoretical sciences (Meyer, 1979). According to Popper's considerable quote that problems are examined and not particular subjects as well as his drawn inference that issues can reach far beyond the boundaries of a specific subject area or discipline paved the way to introduce a generally applicable and usable methodology, establishing binding rules to guide scientists (Popper, 1976).

The critical rationalism specifically emphasizes the fallibility of human knowledge (Gadenne, 2013; Brühl, 2017). The main subject is represented by falsification, which was advocated by Popper (Gadenne, 2002). Thus, falsification refers to an approach of reviewing theories by applying various experiments. Consequently, falsification is taken as the empirical refutation of general statements (Gadenne, 2002). The task of analytical theory of science is to examine theories for falsification and justification. However, formulating theories is attributed to psychology, as a rather creative and irregular process (Brühl, 2017). The methodology of critical rationalism has provided precise and convincing answers, especially for the social sciences, although they are controversially debated (Opp, 2005).

This coursework aims to present critical rationalism and its great thinker Karl Popper as well as Hans Albert. However, this coursework place greater emphasis on Karl Popper as the founder of this school of thought. As a result, the scientific and theoretical foundations of this important school of thought is presented as well as its introduction to Popper's and Albert's explanations. The major currents of epistemology, which were decisive for the development of critical rationalism, are presented right after the introduction, which is part of the second section. Section three starts with Popper's identification of the induction and demarcation problem. Based on the basic problems of induction and demarcation, section four starts to set out the emerging critical rationalism following by a detailed examination of the methodology according to Popper, his theory of falsification, and Hans Albert as an important German representative. Finally, section five contains a critical appraisal and a conclusion.

2. Epistemology

2.1 Rationalism

The term rationalism is derived from the Latin expression ratio with the translation of computation, reason, and consideration (Seiffert, 1997). Rationalism as a current of philosophical reasoning focuses on the view that the world is constituted by logical and lawful predictability, based on intellect and rationality (Brockhaus Philosophie, 2009). Classical rationalism assumes that knowledge can only be obtained through the source of intellect and rationality, and not from sensory experience (Kornmeier, 2007; Brockhaus Philosophie, 2009). Thus, rationalism assumes that scientific findings that are obtained through observation are based on existing or rather established theories and hypotheses (Kornmeier, 2007; Brockhaus Philosophie, 2009). In addition, those scientific findings might also be stimulated by existing and established theories. A non-theoretical experience is ruled out, other source of knowledge than rational thinking is devalued (Kornmeier, 2007). An important characteristic is the exploration of secured knowledge, or rather its verification. Consequently, questions can be solved deductively. Based on fundamental truths, that are derived from a rational argument or intellectual intuition, deduction can support to draw subsequent conclusions. The deductive method aids further scientific findings that are derived from existing findings which is, however, separated from observations of reality or experience (Kornmeier, 2007). Important representatives of this current are René Descartes (1596-1650), who is called the founder of rationalism, Gottfried W. Leibnitz (1646-1716) as well as Baruch de Spinoza (1632-1677) (Brockhaus Philosophie, 2009). A distinction has to be made between epistemological rationalism and empiricism as well as positivism.

2.2 Empiricism

The term empiricism is derived from the Greek expression empeiria and stands for experience (Brockhaus Philosophie, 2009). The term empiricism can be translated semantically into the assertion that knowledge is based on experience (Kornmeier, 2007; Brockhaus Philosophie, 2009). The classical empiricism assumes tabula rasa as a state of mind, which means that the new-borns consciousness is empty (Kornmeier, 2007). The human consciousness acquires substantial knowledge on the basis of experience (Brockhaus Philosophie, 2009). Thus, all acquired knowledge is based on experiences. In contrast to rationalism, assured knowledge is generated by sensory perception as well as observation and, thus, by the process of induction (Chalmers, 2007; Kornmeier, 2007). Consequently, induction is a process of drawing general inferences based on individual observations. The observation of individual facts leads to the creation of experience on which we are able to draw conclusions on underlying theories (Chalmers, 2007; Kornmeier, 2007). The founders of classical empiricism are the Britons George Berkeley, Jon Locke, and David Hume.

The logical empiricism which was inspired by empiricism was originally developed by the Vienna Circle (Herzog, 2012). The Vienna Circle was initiated by the economist and philosopher Otto Neurath. Its most important members were the physicist Philipp Frank, the mathematician Hans Hahn, Moritz Schlick, and Rudolf Carnap. The central objective of this association was the development of a non-metaphysical philosophy to provide the basis for a sensory experience for individual sciences (Mortensen, 2013). Thus, sensory experiences form the core of logical empiricism. Similar to classical empiricism, any cognition by logical empiricism starts with sensory experience. Logic and experience are the two criteria of scientific knowledge that are considered legitimate within logical empiricism (Herzog, 2012). The logical empiricism recognises knowledge only if it is directly verifiable through sensual experience. Theoretical concepts are rejected by the logical empiricism (senseless) that are not anchored in direct experience (Herzog, 2012).

2.3 Positivism

The classical positivism emerged as a philosophical direction and theory of science from the prior developed empiricism (Mises, 1990). This current of philosophical reasoning was founded by Auguste Comte (1798-1857) (Mises, 1990). He described positive as the actual, useful, certain, and precise (Mises, 1990). The meaning positive deviates from the commonly used term in today’s time (Mises, 1990). August Comte was convinced to improve social life on the basis of reflecting on facts in contrast to speculation (Mises, 1990).

Comte's well-known three-stage law outlines an idea of social progress that is divided into a theological stage, a metaphysical stage, and a positive stage of development (Adorno/Dahrendorf, 1969). In the highest stage of development, society approaches the ideal of the positive sciences and renounces all religious or rationalistic explanations in favour of the pure ascertainment of facts (Adorno/Dahrendorf, 1969). According to Comte, various scientific disciplines build on one another, and with help of positive methods like observation, experimentation, and comparison it enables to work out connecting laws between various facts (Adorno/Dahrendorf, 1969, Mises, 1990). This school of thought is characterised by the fact that it accepts scientifically verifiable results. Preference is given to positive aspects resulting from experience and emotions, such as observable facts and evoked perceptions (Kornmeier, 2007; Adorno/Dahrendorf, 1969; Mises, 1990). Thus, in positivism as well as in empiricism experience and human consciousness serves as a basis for the development of theories.

3. Context for the development of Critical Rationalism

3.1 Problem of Induction

David Hume distinguishes between the ideas of reason and research (Hume, 2015). On the one hand, those that relate existing ideas to each other, for instance in the field of mathematics, and on the other hand, those that deal with matters of fact (Hume, 2015).

The idea of reason can generate truth a priori due to logical deduction or mathematical operations, whereas the judgement of matter of facts is not requisite, but solely likely true (Hume, 2015). The objects of perception are not linked to each other through logical operations, but through causal conclusions (Hume, 2015). Consequently, causal conclusions account for the vagueness of validity. Hume suggests that evidence of causal conclusions derive entirely from experience (Hume, 2015).

The following example provides an illustration of Hume’s thoughts. According to Hume, the collision of two objects due to a transmission of force based on an impulse is not indicated by its initial position nor by the movement or halt of the two objects (Hume, 2015). The transmission of force is assumed on the basis of the subjective experience of the observer because such behaviour always occurred. The observer deduces the transmission of force in a collision from its previous observations. Hence, based on the observation that all objects tend to behave similarly, the observer is able to derive general laws that describe this transmission of force mathematically. The fact that such general laws have predictive power for the behaviour of bodies is no sufficient evidence that the effect of the collision itself can be deduced from the causes, the movement of the objects towards each other. It is conceivable that another case will occur, namely that both objects remain in place. In a certain sense, the mental process of causality is free, since it allows for every conceivable possibility. In contrast, relationships such as mathematical operations are not conceivable without contradiction.

Hume structures its factual knowledge into two groups. First, the sensual evident facts, that are directly present to the senses (Hume, 2015). Second, the past or future facts (Hume, 2015). The truthfulness of the first group can be proven easily, simply by referring to them, for instance, “look, it is raining”. However, verifying the truthfulness of the second group is more difficult, because past incidents or future events are not accessible to the senses, for instance, “it rained yesterday, or it will rain tomorrow” (Hume, 2015).

Conclusions drawn from past facts which are used to predict present or future facts are arbitrary. These conclusions drawn are based on similar observations on the basis of other experienced facts as well as their frequency that leads to a habituation process (Hume, 2015). In this way, re-experienced facts seem to be familiar, because the observer considers them to be part of the same class of similarity (Hume, 2015). Conclusions drawn on past facts presuppose that past facts/events are similar to the present as well as the future; past facts are extrapolated to the present and future.

The reasoning that these two tenses are similar cannot be applied a priori either. It is not possible that any justification based on experience can verify the similarity of the past with the future since all these justifications are based on the premise of this similarity (Hume, 2015). Now, conclusions of causality can neither be justified intuitively nor demonstratively. Hume excludes a third kind of justification.

3.2 Demarcation Problem

An important and key problem regarding empirical theories is to distinguish them between those that are empirical as well as those that are not empirical in nature (Keuth, 2002). The demarcation problem is a basic problem of epistemology. Here, the main task is to demarcate the empirical science from formal/exact sciences, such as mathematics, pure logic, and also from metaphysics and pseudoscience (Keuth, 2002; Popper, 1976). The demarcation problem consists of the duty to specify a criterion that provides a distinction between

1. empirical science,
2. mathematics and logic,
3. metaphysics as well as
4. pseudoscience (Popper, 1979; Schülein/Reitze, 2005).

Historically, Popper's initial interest was to demarcate empirical science from pseudoscience. On the basis of the contact to the Vienna Circle, Popper started to become interested in the demarcation of empirical sciences from metaphysics (Keuth, 2000).

Popper started to demarcate at the sentence level (Popper, 1976). Empirical science, metaphysics, etc. define a certain system of sentences (Popper, 1976). The demarcation has the following systematic design: YX which means that a sentence is scientifically precise if X occurs as part of a school of thought (Popper, 1976). In the following, the demarcation is made based on various positions. Y illustrates the designation of the type of criterion (either demarcation or sense/meaning), whereas X shows the content of the criterion (either verificationism or falsificationism) (Popper, 1976).

The D in DX describes the type of criterion which is demarcation, and X the content of the criterion that can take either verificationism or falsificationism. According to Popper, the problem of demarcation is more important than the problem of induction, since the former is more general (Popper, 1976). Moreover, science is a judgemental term. The term is used to impart a certain investigation a particular status. Therefore, it is important to distinguish between real science and pseudoscience.

Inductivism solves the problem of demarcation by assuming that science follows an inductive approach, while logic, mathematics, and metaphysics do not. According to Popper, inductivism is wrong, because science does not follow an inductive approach (Popper, 1976). Thus, Popper needs a new criterion for demarcation.

Popper differentiates between the criterion of demarcation and the criterion of sense/meaning. For the latter criterion, the main question is about the fact when a sentence inherent a linguistic sense/meaning (Popper, 1976). The positivists, such as those from the Vienna Circle represent a verificational criterion of sense/meaning (Keuth, 2000). The systematic design of this school of thought is SV. The S in SV describes the type of criterion which is sense/meaning, and V the content of the criterion that is verificationism (Popper, 1976). A sentence has a sense/meaning if it can be proven by experience whether the sentence is true or false. Thus, the probability of the truth and falsity of a sentence is dependent on fundamental principles (Popper, 1976). These fundamental principles reflect the experience and are therefore not problematic for both empiricists and positivists.


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Critical Rationalism by Karl Popper and Hans Albert
ESCP Europe
Philosophy of Science
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Critical Rationalism, Karl Popper, Hans Albert, Philosophy of Science, Kritischer Rationalismus
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Simon Valentin (Author), 2021, Critical Rationalism by Karl Popper and Hans Albert, Munich, GRIN Verlag,


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