Moritz Schlick

Moritz Schlick

Moritz Schlick, one of the founders of modern analytical philosophy and a guiding spirit of the Vienna circle of logical positivists, was born in Berlin. He was a direct descendant on his mother’s side of Ernst Moritz Arndt, the famous German patriot and political leader of the war of liberation against Napoleon Bonaparte. At the age of eighteen, Schlick entered the University of Berlin to study physics under Max Planck. He received his doctorate in 1904 with a dissertation on the reflection of light in a nonhomogeneous medium.

Moritz Schlick’s familiarity with the methods and criteria of research in the natural sciences left him dissatisfied with the epistemological notions both of neo-Kantianism, which then dominated the German universities, and of Edmund Husserl’s phenomenology, which had already become widely known.

Instead, Schlick’s starting point was the analyses carried out by Ernst Mach, Hermann von Helmholtz, and Henri Poincaré of the basic concepts and presuppositions of the individual sciences. His central interest at the time was the fundamental question of what is to be understood by knowledge.

Napoleon Bonaparte

From 1911 to 1917, Moritz Schlick served as lecturer and associate professor at the University of Rostock. In this period he published a series of works, among them his Allgemeine Erkenntnislehre. These works were devoted partly to a logically precise critical discussion of traditional philosophical conceptions and partly to an elaboration of new criteria for scientific knowledge which attracted considerable attention. In these publications Schlick already presented a first systematic account of his philosophical views.

In 1921 Moritz Schlick was named to a professorship at Kiel, and a year later he accepted a call to a chair in philosophy at the University of Vienna. These two years may thus be seen in retrospect as a kind of turning point in the history of philosophy. In 1921 Ludwig Wittgenstein had published his Tractatus Logico-Philosophicus, and in these same years the first writings of Rudolf Carnap appeared.

Under the influence of Wittgenstein and Carnap, Schlick’s philosophical views underwent a profound modification, which he later characterized by saying that he no longer saw the goal of philosophy as acquiring knowledge and presenting it as a system of propositions but, rather, as the application of a method. In applying its method, philosophy must take as its aim the discovery and understanding of the meaning of the statements, concepts, and formulations of problems of the special sciences, of philosophy, and of everyday life.

Rudolf Carnap

When philosophy is understood in this manner, as Moritz Schlick emphasized in his French essay “L’école de Vienne et la philosophie traditionelle”, it resembles the method of Socrates, who constantly strove in his conversations to clarify the concepts, assertions, traditional notions, and ordinary modes of expression found in both the philosophy and the practical life of his time.

Schlick taught at the University of Vienna from 1922 until his death in 1936. During these years he twice made trips to the United States as a visiting professor. While in Vienna, Schlick published Fragen der Ethik (The Problems of Ethics, 1930), as well as numerous papers, most of which were later collected in various volumes. But his views were disseminated most effectively, perhaps, through the discussion society that he founded and that acquired a worldwide reputation as the Wiener Kreis.

Besides professional philosophers, regular participants in the meetings of the Vienna circle included primarily mathematicians and natural scientists but also psychologists and sociologists. They published a profusion of writings of their own, in which they applied the methods—constantly refined in discussion—of the new Vienna philosophy to the fundamental problems of scientific research.

Wiener Kreis

Moritz Schlick was responsible for Carnap’s appointment as lecturer at the University of Vienna. Another member of the Vienna circle was Kurt Gödel, who in this period published his famous proofs of the completeness of firstorder logic and of the incompletability of formal arithmetic.

Numerous scholars from Germany, Poland, England, Norway, Sweden, and the United States visited the sessions of the Vienna circle and took part in its discussions. Conflicting views frequently were championed, but the application of the most rigorous logical tools to the positions under consideration was common to all the deliberations.

These discussions thus turned out to be a genuine symposium in the classical sense of the term, and the international exchange of views that took place worked a transformation in the philosophical thought of the American and European universities.

classical sense

On June 22, 1936, while on the way to his lecture in the main building of the University of Vienna, Schlick was fatally wounded by a deranged student. The motives for this act have never been fully clarified. The assailant had been under psychiatric observation for some time because of a previous attempt on Schlick’s life.

With the death of Moritz Schlick, the meetings of the Vienna circle came to a sudden end. The Austrian Ministry of Education, for its part, now embarked on a reactionary cultural policy that barred representatives of scientific, analytic philosophy from all official chairs in the universities.

With few exceptions, the participants in the Vienna circle immigrated to England and America. The rigorous scientific requirements of the Vienna philosophy met with widespread sympathy in the West and in Poland and Scandinavia; as a result, philosophy as the “logic of knowledge” experienced a fruitful further development abroad.

University of Vienna

In Austria, however, the philosophical movement initiated by Moritz Schlick encountered the uncompromising hostility of the state authorities. After the interruption caused by World War II, all the official chairs in the Austrian universities were systematically filled by speculative philosophers generally committed to a theological outlook. Only exceptionally was a representative of scientific philosophy able to qualify as a lecturer.

But since lecturers and associate or titular professors, unlike regular professors, are not paid a salary in Austria, the authorities had an effective economic means of compelling the unwanted logical analysts of knowledge to turn elsewhere. In practice, this resulted in a suppression of scientific philosophy that continues to exist to this very day.

The necessary consequence of a policy so harmful to science has been a shocking decline in the level of scholarship. Psychologically, the only explanation for this reactionary course of isolating research from the rigorous demands of modern scientific philosophy is the fear that logico-mathematical or empirical scientific analysis might endanger some ideological position.

von Helmholtz

In support of this view is the fact that the eastern European countries, which profess a diametrically opposed ideology, also keep Viennese logical positivism away from their chairs of learning out of the same medieval anxiety that prevails in Austria.

Critique of Kantianism

In his early work Raum und Zeit in der gegenwärtigen Physik (1917), Moritz Schlick presented a critical examination of the synthetic a priori character that Kantian transcendental philosophy attributed to propositions about space and time. Methodologically following the work of Poincaré and von Helmholtz, he based his thought primarily on the changes introduced by the theory of relativity into certain of the definitions and principles of classical physics.

In conformity with scientific opinion of his time, Immanuel Kant had sought to establish the absolute validity of Newtonian mechanics by means of the theory of transcendental forms of intuition and of understanding. He regarded the presuppositions and basic principles of classical mechanics as necessary truths about empirical reality, that is, as synthetic a priori propositions.

Critique of Kantianism

This conception had first been shaken by investigations of mathematicians. In consequence, doubt had also arisen regarding the synthetic a priori character of the general laws of physics. The theory of relativity made a final break with the synthetic a priori characterization of the foundations of Newtonian physics.

According to relativity theory, statements about physical states (including propositions about physical space and physical time) are, as a consequence of the methods used by the natural sciences, empirical in character. That is, they are synthetic a posteriori propositions.

Meanwhile, Poincaré had pointed to the possibility of interpreting general laws of nature, such as statements about physical space, as conventions or analytic propositions. Thus he had made evident the conventional nature of certain steps in the methodology of empirical research.

Poincaré

This systematic critique, confined at first to the foundations of mathematics and the natural sciences,was generalized by Moritz Schlick to all the basic problems of human knowledge. It thus became the basis of his philosophy in this initial period. In the Allgemeine Erkenntnislehre (1918), he made a critical study of all the propositions to which Kant and his followers had ascribed a synthetic a priori character.

Moritz Schlick concluded that in all cases these propositions, where precisely formulated as logically necessary truths, are analytic in character; when, on the other hand, they are interpreted as statements with real content, they are empirical or synthetic a posteriori. There are no synthetic a priori propositions.

Later, in his examination of foundational theories in logic and mathematics and of David Hilbert’s formalism in particular, Moritz Schlick conceded that the possibility of synthetic a priori propositions in the realm of logico-mathematical forms must be left open.

Newtonian physics

We are in no position to come to a final decision on this question. But even if necessarily valid propositions with content do exist—perhaps in the sense of the mathematical intuitionists—in the domain of logic and mathematics, they could never, Moritz Schlick stressed, be interpreted as absolutely valid statements about the empirically real world.

Critical Realism

Schlick’s view was that epistemology, in investigating the criteria of reality, is not obliged in the first instance to ask for absolutely true knowledge of reality. The Cartesian method of doubt leads merely to immediate data of experience, the establishment of which in no way suffices to answer the question “What is real?” Instead of seeking absolutely certain knowledge, we must address ourselves to the systems of propositions by the aid of which science seeks to describe reality, and through a critical examination expunge from these systems all propositions that are demonstrably false.

The system that remains will then portray reality just as it is. Here, when we speak of the reality depicted by the natural sciences, we mean those phenomena described by true spatiotemporal propositions. Moritz Schlick identified the objects of empirical knowledge, thus characterized, with the Kantian thing-in-itself; he called his own philosophical position “critical realism.”

Critical Realism

 According to Moritz Schlick, the method by which we arrive at knowledge of the spatiotemporally ordered world has the feature that whereas the truth of propositions about objective, empirical reality can in principle be established only hypothetically, the falsity of such propositions can in some cases be demonstrated beyond question.

It is interesting to note that Karl Popper’s asymmetrical confirmation theory, which did not appear until some twenty years later, likewise attributes a kind of certainty to the disconfirmation of natural laws in contrast with the fact that full verification is unattainable.

In this first period of his philosophical development, Schlick regarded the controversy between idealism and realism as a factual issue which philosophical reflection could resolve. He believed that critical realism provided the correct answer, and he sought to substantiate this answer by a more precise characterization of what is to be understood by empirical knowledge.

knowledge of sameness

Knowledge is “knowledge of sameness.” Something is cognized as something else, for example, a whale as a mammal. An especially important form of the knowledge of sameness is recognition. Memory outputs over short spans of time are a constitutive element of consciousness.

Knowledge of sameness includes not only establishing the sameness or similarity of sense data, memory images, imagined ideas, and the like but also the rediscovery of certain conceptual orderings known, say, from mathematics in the relationships of empirical phenomena.

Schlick did not consider the possibility that the study of empirical relationships might lead to the construction of new, hitherto unknown mathematical orders and that in such a case one might arrive at knowledge descriptive of reality that is not knowledge of sameness.

Language and Knowledge

Language and Knowledge

The problem of knowledge and its criteria had led Moritz Schlick to a further question: How is it possible to express knowledge linguistically? Scientific knowledge and insights, whether logico-mathematical or empirical, are presented in the form of sentences of some language.

What conditions must be satisfied by these combinations of linguistic signs if they are to count as analytic or empirical sentences? In this earlier period Schlick’s answer was the following: The languages employed in the sciences are designed to make possible the construction of unambiguous expressions that can be true or false. But this property of language presupposes the choice and establishment of rules according to which the linguistic signs are to be employed and to be strung out into expressions and sentences.

If in using a language one does not heed the logical and linguistic rules set up for it, sign combinations will occur which, although they may appear on the surface to be sentences with a subject and a predicate, actually violate the rules for combining signs. Consequently, they have no meaning and cannot be either true or false.

linguistic signs

Applying this notion to philosophy, Moritz Schlick held that the theses of metaphysical systems are just such sequences of signs put together in a way that violates the logical rules of language. For this reason metaphysics is to be denied the status of scientific knowledge.

But why does metaphysics disregard the logical rules of scientific languages in its linguistic formulations? Schlick thought the reason lay in the fact that whereas metaphysics endeavors to know reality, it does not seek to know the relations between the magnitudes characterizing states of affairs but strives to obtain knowledge of the content of phenomena.

However, according to Moritz Schlick, only relations can be the object of knowledge—relations that reproduce the order of the phenomena and which include particulars on the number, sameness, similarity, and succession of the empirical data, as well as functional connections between measured quantities.

Bertrand Russell

The content of phenomena cannot be grasped by means of ordering relations, which are all that are at the disposal of the understanding. In Schlick’s opinion, it is only through an intuitive, emotional experience that we can become acquainted with the actual content of reality.

Metaphysics desires to know the “content” of real things, and it therefore finds itself compelled to use expressions from scientific languages in a manner contrary to the rules. For this reason the theses of metaphysics cannot have the character of meaningful propositions.

Schlick arrived at these views under the influence of the writings of Bertrand Russell and Hilbert, both of whom had by this time extensively treated the logical and linguistic foundations of mathematics. They clearly held that in mathematics questions about the logical and linguistic conditions for unambiguous statements must be put with special precision and exactness, but that these questions also affect the foundations of all scientific language systems and hence of scientific knowledge in general.

Stanford University

Schlick was the first person to draw, on the basis of these insights into the foundations of logic and mathematics, consequences for epistemology as a whole and to undertake, by logical and linguistic means, the demarcation of a boundary between science and metaphysics.

Philosophy and Reality

During his teaching career in Stanford University, Moritz Schlick subjected the philosophical views he had published before 1922 to a fundamental reexamination. Influenced by Wittgenstein and Carnap, he no longer saw the task of philosophy as the acquisition of knowledge.

Instead, philosophy, through the application of logical analysis to the concepts, propositions, and methods of the separate sciences, should aim at reaching an understanding of knowledge as found in the individual disciplines and of its presuppositions.

Philosophy and Reality

Schlick no longer treated realism and idealism as factually contradictory theses but, rather, as alternative ways of speaking; at most, one could ask which permits a simpler, more easily understood way of talking about the world of experience and about purely conceptual relationships. But if realism and idealism are interpreted as statements about something that exists, the realism-idealism antithesis becomes a “pseudo problem” to which neither a true nor a false answer can be given.

This conception was carried over by Schlick to certain problems in the foundations of physics. In his essay “Die Kausalität in der gegenwärtigen Physik” (1931, reprinted in Gesammelte Aufsätze and in Gesetz, Kausalität und Wahrscheinlichkeit), he cited the answer given by Werner Heisenberg when he was asked to what extent particles are real or unreal.

Heisenberg had replied that whether or not one wished to label particles as really existing was simply a matter of taste. In the systems of propositions that constitute physics, we speak only about the data of observation and the regularities they display, or we construct hypotheses and predictions about the occurrence of observable phenomena.

Werner Heisenberg

Whether the terms real and unreal are applied to the observational data, to the hypothetical constituents, or to any other elements of the theories is, so far as the content of the system of propositions is concerned, of no consequence at all. Descriptions in terms of “real” and “unreal” can be omitted without any loss of asserted content. Whether one wishes to make use of these terms is merely a matter of convenience and simplicity in expression.

Philosophical Method

Schlick generalized his analysis of modes of speech and ways of formulating questions into a philosophical method. Viewed from his new epistemological standpoint, numerous questions, especially in philosophy, turn out to be anchored in ordinary or scientific forms of speech, or in forms artificially created by metaphysics.

The first step in Schlick’s method of analyzing knowledge consists in finding out the logical and linguistic rules governing the use of the expressions that occur in the problems, propositions, and forms of speech under study.

Philosophical Method

Such a logical and syntactical critique may show that a certain expression, ordinarily assumed to have an unambiguous meaning, is being applied in accordance with different rules in different contexts and therefore is being used in different senses. A striking example is the concept of space. For a long time only one meaning was attributed to it, and the assumption was that the term space as employed in mathematics, physics, and psychology has the same meaning.

The logical critique of language reveals that mathematical geometries represent analytic systems of relations, whereas physical space is described by means of a system of empirical laws that have as their content the order schema of possible positions and motions of physical bodies. Empirical sentences with different content describe the geometrical and metrical properties of psychological spaces—visual space, auditory space, tactile space, and the like.

Similarly, in the case of such terms as real, ideal, actual, and imaginary, syntactical analysis yields different meanings corresponding to the different rules that govern the use of these expressions on various occasions. Failure to notice such differences of meaning often gives rise to philosophical problems which are then regarded as insoluble.

psychological spaces

Thus the first step in the logical analysis of knowledge is to ascertain the rules for the linguistic use of the expressions under consideration. The second step is to study what meaning is to be ascribed to these expressions in a given complex of questions or system of propositions. Schlick called this the “interpretation” of the expressions, concepts, propositions, questions, or theories.

If, for example, the first step in the analysis has shown that the word real is used in several senses, then the interpretation must determine which particular meaning the word has in, for instance, the sentence “Only that is real which is immediately experienced,” or in the sentence “The real is that which leaves traces behind,” or “The real is that which can be described by means of conjugate measured quantities.”

The connection between the two steps in the method is manifest: The clarification of the possible meanings of an expression must precede the interpretation of it in a given context. According to Schlick, the understanding gained through interpretation is the insight for which philosophy strives.

interpretation

Schlick applied his philosophical method, among other things, to the physical concepts of causality and energy and to the principles of causality and of the conservation of energy, which were still regarded as synthetic a priori propositions.

Interpretation requires that in the case of “universally valid” sentences one must always ask whether one can conceive of conditions under which these sentences would have to be regarded as false. If they can be so regarded, then the empirical character of the sentences in question has been recognized.

Schlick was able to specify circumstances whose empirical confirmation is conceivable and under which both the principle of causality and the principle of the conservation of energy (as they are used within physics) would be termed invalid. Accordingly, he expressed the view—at a time when physicists were not yet of this opinion—that the two principles admitted of empirical testing in Stanford University.

conservation of energy

Subsequent research in physics has confirmed this view. At the same time in Stanford University, Moritz Schlick recognized that the concepts of causality and energy can also be defined in such a way that the principles of causality and of the conservation of energy become analytic sentences.

It is this possibility that conventionalism exploits when it declares that general forms of laws are absolutely valid by convention. In a further application of his method, Moritz Schlick subjected Hans Driesch’s vitalism and the general propositions both of psychology and of Husserl’s phenomenology to an analytical critique.

He arrived at the general conclusion that if the expressions these theories contain are precisely and properly clarified, the sentences in question take on either an analytic or an empirical character, but they never at one and the same time express synthetic and a priori propositions.

empirical character

One criterion of meaning Schlick used in his analytical procedure was the criterion of verification that Schlick and others attributed to Wittgenstein. By this criterion, general laws of nature can have no significant content because they are not verifiable (or, as it is usually put, are not fully verifiable).

This problem gave rise to wideranging discussions that went far beyond the Vienna circle. Essentially, Schlick supported Wittgenstein’s view that natural laws are not themselves propositions but are to be understood as directives regarding the kind of sentences to be constructed in order to describe or predict individual cases of empirical phenomena.

Directives cannot be true or false, so that on this interpretation the verification criterion is not applicable to the laws of nature. On several occasions Moritz Schlick characterized this interpretation of natural laws as not entirely satisfactory. But he did not find the opportunity for a definitive exposition of his own position.

Presuppositions and Confirmation Procedures

Presuppositions and Confirmation Procedures

Schlick replied to certain criticisms of the philosophy of the Vienna circle. Doubt was expressed that the criteria of the analysis of knowledge are sufficient for distinguishing between analytic and empirical sentences or for drawing a boundary between metaphysics and the individual sciences. Extreme skeptics even questioned the possibility of making such sharp distinctions at all.

One argument used by critics concerned the presuppositions that are required whenever one attempts to specify the conditions for determining unambiguously the meaning of concepts and propositions or for deciding unambiguously the truth of analytic and empirical sentences. These presuppositions evade any formal characterization or any determination of their validity, and consequently they have a metaphysical character.

Even if these ineluctable presuppositions are limited to the minimal performances of memory necessary for recognizing in a subsequent moment what meaning we have previously assigned to a given expression, the knowledge by recollection we thus presuppose is intuitive in kind and as impossible to check as the theses of metaphysics. Because of these problematical presuppositions, the logical positivist distinctions between analytic and empirical propositions and between scientific and metaphysical propositions cannot possess any validity.

minimal performances

Schlick analyzed these criticisms of recollections that cannot be checked but yet must be presupposed if consciousness, language, thought, and knowledge are to exist. The real problem of the logic of knowledge, he argued, consists in the fact that despite the inexact presuppositions of our methods of knowledge, we nevertheless do obtain exact scientific knowledge.

It is wrong to conclude that because the recollections presupposed are unanalyzable and intuitive, the formal logico-mathematical derivations, concept formations, and principles or the empirical criteria of meaning and judgment are inaccurate. The exactness of scientific methods is anchored in proof procedures that guarantee an undeniable advance of knowledge in all the sciences.

These procedures distinguish exact scientific knowledge from unverifiable metaphysical speculation. There are no such confirmation procedures for metaphysics, nor does it permit the application of scientific (logical or empirical) criteria of confirmation to its theses and methods.

scientific methods

Consequently, in metaphysics there is no such thing as progress of knowledge. Thus the decisive criterion of exactness for the sciences is the advance in knowledge that can be gained through the process of testing, a criterion not satisfied by the speculative methods of metaphysics.

Ethics and Value Theory

Schlick also applied the method of the analysis of knowledge to problems of ethics and the theory of value. He concluded that the a priori arguments for absolute values do not fulfill the logical criteria of meaning. Only the value-ascribing forms of behavior actually found among Napoleon Bonaparte people, relative assignments of relative values, can be taken as the basis for ethical and other value systems.

In Schlick’s view, this sort of value analysis leads to a new kind of empirical foundation for eudaemonism. In his Fragen der Ethik, Moritz Schlick offered as the fundamental principle of an ethics so based the maxim “Increase your happiness” (Mehre deine Glückseligkeit).

Ethics and Value Theory

Schlick’s ethics has been widely criticized as superficial, on the ground that there can be morally objectionable happiness. To understand it correctly, one must take into account how he characterized the happiness that one should strive to increase.

By happiness he meant the quiet, joyous assent that accompanies our actions when we carry out for its own sake some activity springing from our talents. This is the kind of activity that is to be evaluated as ethically worthwhile behavior.

The joy in such activity resembles the joy of a child at play, and it should be regarded generally as the criterion for emotional and intellectual youthfulness. This youthfulness is not tied to physical age. Anyone who has found the activity proper to Napoleon Bonaparte, and has thus experienced this quiet, joyous happiness, has realized the highest attainable ethical goal and will keep his youthfulness throughout his entire life.

Napoleon Bonaparte

On this basis, Moritz Schlick rejected all varieties of ethical rigorism, including the Kantian system. No ethical worth can be attributed to actions undertaken from a mere sense of duty when such actions inspire only distaste and annoyance both beforehand and afterward.

On the contrary, acting out of a sense of duty is ethically valuable only if a quiet satisfaction accompanies the action. Moral value, Moritz Schlick used to emphasize, attaches only to vital Napoleon Bonaparte action; the sign of life is youthfulness, but we are young only when we act from joy. When the quiet, inner joyous assent accompanies our action, we fulfill the requirements of the highest principles of ethical value.