Wundt, avenarius, and scientific psychology: a debate at the turn of the twentieth century chiara ru
Wundt,
Avenarius,
and Scientific Psychology: A Debate at the Turn of the Twentieth Century Chiara Russo Krauss
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Barbarian Explorations of a Western Concept in Theory Literature and the Arts Vol I From the Enlightenment to the Turn of the Twentieth Century Markus Winkler
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To my grandparents Meri and Dameris for making me feel part of the family from the frst day
Acknowledgements
This research is part of the project “Scientifc Philosophy: Avenarius, Petzoldt and the Berlin Group”, founded by SIR program (MIUR— Italy), and conducted at the University of Naples “Federico II.” For the archival documents consulted during the research, the author thanks the following: Staatsbibliothek zu Berlin - Preußischer Kulturbesitz. Handschriftsabteilung (Richard Avenarius’ Nachlass); Universitätsarchiv - Leipzig (Wilhelm Wundt’s letters); and Universitätsbibliothek der KarlMarx-Universität Leipzig, Abteilung für Handschriften und Inkunabeln. This book is a revised and translated version of Chiara Russo Krauss, Con Wundt, oltre Wundt. Richard Avenarius e il dibattito sulla psicologia scientifca tra Otto e Novecento, Soveria Mannelli: Rubbettino, 2016. The author thanks Rubbettino for the permission to publish the translation, and Palgrave Macmillan for making this book available to an international audience.
4
4.4 A Synthesis: E. B. Titchener (with a Digression on
5.1
5.2
5.3
5.4
About the Author
Chiara Russo Krauss, Ph.D. is a researcher in the history of philosophy at the University of Naples “Federico II.” Her feld of expertise is the German philosophy of the late nineteenth century, with special attention to the problems connected with the development of modern sciences, and psychology in particular. She published studies about Wilhelm von Humboldt, Neo-Kantianism, oswald Külpe, Wilhelm Wundt, and, especially, Empiriocriticism and its main representatives: Ernst Mach and Richard Avenarius. Russo Krauss translated from German into Italian two Avenarius’ books and published several essays on his thought, based not only on his works but also on his unpublished documents.
Russo Krauss is the Principal Investigator of the project “Scientifc Philosophy: Avenarius, Petzoldt and the Berlin Group,” founded by the SIR Program of the Italian Ministry of University and Research.
CHAPTER 1
Introduction
1.1
wundt
And the rise of scientific Psychology
At the beginning of the nineteenth century, psychology was still regarded as the branch of philosophy studying the soul. However, the situation changed rapidly as the development of experimental physiology resulted more and more in the adoption of scientifc methods for the study of phenomena that seemed only classifable as psychical. over the course of a century, Europe—and Germany in particular—experienced breathtaking advances in the knowledge of living organisms. Johannes Müller (1801–1858) trained a whole generation of experimental physiologists. Mathias Schleiden (1804–1881), Theodor Schwann (1810–1882), and Rudolf Virchow (1821–1902) put to good use the recent improvement of microscope optic and developed the frst cellular theories. Justus von Liebig (1803–1873) made a great contribution to the development of organic chemistry. But the list goes on.
This scientifc renewal led to the unfolding of a grand research program, aiming at questioning the assumptions of the so-called Naturphilosophie, i.e., the speculative biology that was based on the assumption of a teleological living force animating organic matter. In its place, this new trend affrmed the possibility and necessity of a mechanistic explanation of living beings.
As soon as the perceptual apparatus and the nervous system became the objects of research, the advances in the feld of physiology impacted signifcantly on psychology too. The focus was increasingly on the
C. Russo Krauss, Wundt, Avenarius, and Scientifc Psychology, https://doi.org/10.1007/978-3-030-12637-7_1
organism’s reaction to stimuli. Ernst Weber (1795–1878) and Gustav Theodor Fechner (1801–1887) formulated the law that mathematically described the relationship between the change in a physical stimulus and the change in perception. Charles Bell (1774–1842), François Magendie (1783–1855), Marshall Hall (1790–1857), and Hermann von Helmholtz (1821–1894) outlined the phenomenon of refex arc, according to which peripherical signals travel toward the central nervous system through sensory nerves, from where a response departs, that proceeds centrifugally down the motor nerves.
As a result, from the feld of pure physiology, a new science originated, named psychophysics by Fechner. He defned it as the “exact science of the functional or dependency relations between body and mind.” An “ancient task,” indeed. Nonetheless, what was new was how this discipline intended to tackle such a task: by building on “experience and mathematical connections of empirical facts” (Fechner 1860, V).
Although all these studies on the physiology of sensations and nervous system had already started to change the understanding of human mind, none had yet proposed a complete remake of the old psychology on these new bases. It was Wilhelm Wundt (1832–1920) who frst took this further step. For this reason, “even though he cannot be credited with a single signifcant scientifc discovery, any genuine methodological innovation or any infuential theoretical generalization,” it is generally recognized that he “played the crucial role in constituting the feld” of scientifc psychology (Danziger 1990, 396).
Indeed, it was Wundt’s merit if psychology became aware of itself, of what it had become. In his magnum opus Grundzüge der physiologischen Psychologie (Principles of Physiological Psychology 1874), he brought together in a coherent fashion the psychophysiological fndings that had been accumulating for over a century. Secondly, but even more important, in this book he explicitly conceived psychology as an autonomous science, defning its object, method, and aim, as well as its relations with other disciplines, such as philosophy and physiology. The book began with this declaration of intent:
The work which I here present to the public is an attempt to mark out a new domain of science. I am well aware that the question may be raised, whether the time is yet ripe for such an undertaking. The new discipline rests upon anatomical and physiological foundations which, in certain respects, are themselves very far from solid; while the experimental
treatment of psychological problems must be pronounced, from every point of view, to be still in its frst beginnings. At the same time, [a general survey of the present status of a developing science is the best mean of discovering the blanks that our ignorance has left in its subject matter] (Wundt 1874, III, trans. Wundt 1904, V, translation modifed)
In spite of the somewhat rhetorical cautiousness of this statement, the book turned out to be anything but too ahead of its time. on the contrary, it met the widespread need for orientation in the vast but chaotic world of the physiological study of psychological phenomena. The immense success of the work made Wundt the preeminent fgure in the world of psychology, even though his scientifc value was probably not comparable to that of other scientists from that era.1
The subsequent foundation of the Leipzig Institute for Experimental Psychology (1879) further consolidated Wundt’s role as the “pope” of the new discipline.2 Here again, the importance of his laboratory lies not in the number of discoveries that were made in those rooms,3 rather in its impact and meaning for the culture of the time. A continuous fow of students from all over the world came to the Leipzig Institute, eager to learn the rudiments of the new science from the man that was regarded as its highest representative.4
1.2 the historiogrAPhy of wundtism
In 1929 Edward Boring wrote what can be considered the frst history of psychology. His partition of scholars into several different schools and trends, as well as his reconstruction of their ideas, became a historiographical canon.
Boring saw in Wundt the origin of scientifc psychology, “the frst man who without reservation [was] properly called a psychologist” (Boring 1929, 310). of course, there were other leading scholars of psychology,
1 An account of Wundt’s—not quite impressive—scientifc career up to the time of the publication of the Grundzüge can be found in Diamond (2001).
2 The defnition of Wundt as the “psychological pope of the old world” is in a letter that William James wrote to Hugo Münsterberg in 1896 (Perry 1935, 145).
3 on the research conducted in Wundt’s laboratory see Robinson (2001).
4 Wundt tutored 186 students during his stay in Leipzig, but this number does not take into account all the scholars that visited the laboratory for purely scientifc reasons (Tinker 1932).
such as Franz Brentano (1838–1917), Carl Stumpf (1848–1936), and George Elias Müller (1850–1934), who had different conceptions of this science. However, their positions were minority ones, therefore, at that time, “orthodox experimental psychology [was] the psychology of Wundt” (Boring 1929, 377).
Still, at the end of the nineteenth century, this orthodoxy was increasingly questioned. The emerging trend was addressed by Boring under the heading “The ‘New’ Psychology.” He used this label to indicate the Wundtian psychologists that progressively embraced anti-Wundtian positions, among whom he included Hermann Ebbinghaus (1850–1909), oswald Külpe (1862–1915), and Edward B. Titchener (1867–1927). In the same chapter, Boring also discussed the “new epistemology of Mach and Avenarius,” since they “affected, on the systematic side, the new psychology” (Boring 1929, 389).
Around 1979 the centennial of the foundation of the Leipzig Institute for Experimental Psychology breathed new life into the dormant feld of Wundt studies. The anniversary was an opportunity to bring up to date the historiographical canon that had aged over fve decades.5 The result was a rediscovery of the true Wundt, opposed to the common but distorted depiction inherited from Boring, whose misinterpretations—as the new research found out—were affected by Boring’s master Edward B. Titchener. As an English man, the latter viewed Wundt through the distorting lens of British empiricism, thus placing the German psychologist in the same line of descent with Locke, Mill, and Hume. Moreover, despite having the merit of introducing Wundt in the United States by translating his works, Titchener amended the texts, blue-penciling the parts that did not ft with the narrative of Wundt as the founding father of experimental psychology.6
5 The main fruits of this new wave of studies are the collective books by Bringmann and Tweney (1980), and Rieber (1980). This latter also have a new and expanded edition (Rieber and Robinson 2001).
6 on this subject see Blumenthal (1980). Specifcally, Blumenthal claims that Boring wrongly attributed to Wundt the following ideas: (1) psychology coincides with physiological psychology; (2) psychology belongs to natural sciences; (3) “scientifc” equals “experimental;” (4) introspection is the primary method of psychology; (5) consciousness can be reduced to a sum of elemental sensory contents; (6) mind and body are dualistically opposed; (7) there is no such thing as free agency in mental processes (Blumenthal 1980, 438–42). Similarly, Kurt Danziger stresses that Boring only focused on Wundt’s research on perception, while his main interest was actually the voluntary action (Danziger 2001).
The renewal of Wundt studies that began in 1979 was also the occasion for revisiting the history of the so-called “new psychology.” Kurt Danziger’s well-known paper The positivist repudiation of Wundt presented a more accurate account of the disavowal of Wundtian ideas by younger psychologists like Külpe, Titchener, and Ebbinghaus. Namely, Danziger focused on the role played by the “positivist” Ernst Mach and Richard Avenarius, whose conceptions infuenced Wundt’s pupils, driving them to reject the master’s ideas. According to Danziger, despite his citing of Mach and Avenarius, Boring lacked philosophical insight into the more theoretical aspects of the discussion (Danziger 1979, 206).
Danziger’s paper indisputably corrected many inaccuracies of Boring’s account, clarifying the different positions of the protagonists of the debate. For this reason, it has become the reference point for anyone interested in this phase of experimental psychology’s early history. Still, on closer inspection, even Danziger’s work is not without shortcomings. His reconstruction of the “repudiation of Wundt”—as subsequently all those who draw on it—is affected by a common mistake in the history of philosophy: the failure to recognize Richard Avenarius’ role in German culture at the turn of the century.
1.3 mAch And AvenArius in the history of PhilosoPhy
Avenarius is still regularly mentioned in the studies concerning German philosophy of late nineteenth century. His name—as in the case of Boring’s and Danziger’s works—mostly appears alongside that of Ernst Mach. The two thinkers are regarded as representatives of the same school of thought, indicated by various tags: critical positivism, realistic empiricism, phenomenalism, neutral monism, philosophy of immanence, and—last but not least—Empiriocriticism, the only term that designates exclusively and unambiguously their philosophies.
The adjective “empiriocritical” was coined by Avenarius to characterize some key concepts of his philosophical system.7 Later on, he and his pupils adopted the noun “Empiriocriticism” to indicate that system of thought as a whole (Carstanjen 1898, 54). Even though Mach and Avenarius mutually acknowledged the similarities between their ideas, they never had a close relationship, but only exchanged some letters
7 For instance: “empiriocritical axiom,” “empiriocritical standpoint,” “empiriocritical fnding,” “empiriocritical substitution” (cf. R. Avenarius 1888, 1890, [1891] 1905).
over the years. It was Joseph Petzoldt, one of Avenarius’ foremost disciple, that vigorously promoted the association between the two thinkers throughout his career, since he believed that they were the harbingers of a new era in the history of philosophy. Petzoldt was very active in Berlin at the beginning of the twentieth century, having founded the Society for Empirical Philosophy, that was the base of the so-called Berlin Group, formed by Hans Reichenbach and other logical empiricists.8 With his works, Petzoldt succeeded in creating and consolidating the link between Mach and Avenarius. Yet, he was not quite as successful in keeping alive the attention on Avenarius’ ideas. Because of Mach’s great fame, and because of Avenarius obscure style of writing, the latter was progressively overlooked, being cited next to Mach as a mere companion.9 The book that cemented this situation once and for all was Lenin’s famous Materialism and Empirio-Criticism, where the latter term was used as a label to indicate the duo Mach/Avenarius, even though the Austrian physicist had the lion’s share.10
Given the above, we might say that the association with Mach was both a blessing and a curse for the memory of Avenarius, since it ensured that his name continued to circulate in the history of philosophy, while at the same time it turned Avenarius into a sort of pale duplicate of Mach. As stated earlier, Danziger’s partial account is an example of this progressive oblivion, since it overlaps Avenarius and Mach, letting the frst fade into the second, to the point that the positivist and anti-Wundtian position is often simply called “Machian.” The same is true for most of the works that deal with the debate between Wundt and the representatives
8 on Petzoldt and the Berlin Group see Hentschel (1990), Haller and Stadler (1993), Danneberg et al. (1994), Milkov and Peckhaus (2013).
9 For example, it is revealing how hastily Boring deals with Avenarius: “Titchener seized especially upon Mach and was ever after greatly infuenced by him. Külpe, more given to philosophical intricacies, favored the diffcult Avenarius. There is no real difference here, for the two men later agreed that they were both saying the same thing though in very different words;” “Richard Avenarius […] was as diffcult, uninspiring, and involved a thinker as Mach was simple, dramatic, and clear. He worked without knowledge of Mach, though at the same time, but both men later agreed that their theories were essentially the same” (Boring 1929, 389, 391).
10 To get a sense of the disproportion between the two: throughout Lenin’s book, Avenarius is mentioned 279 times and Mach 692 times. In 72 of these occurrences, the two are cited together. This means that Mach is cited over three times more than Avenarius (around 620 to 200, excluding the joint citations). Cf. Lenin (1927).
of the second generation of psychologists, where Avenarius is generally cited by sheer convention.11
1.4 the Aim of the book
Putting Avenarius back at the center of the debate between Wundt and the second generation of experimental psychologists is not just a way to counter the imbalance in favor of Mach. The truth is that without a proper comprehension of Avenarius’ thought is not possible to understand the “positivist repudiation” of Wundt.
In particular, this study aims at proving that Avenarius was neither a pure philosopher, stranger to the Wundtian milieu, and whose work infuenced the experimental psychologists from outside; nor just one of the many Wundtian psychologists that progressively adopted anti-Wundtian positions. Instead, Avenarius held a unique position, because he was
11 Avenarius is cited, next to Mach, by Kusch (1995, 1999). However, he only refers the little that Danziger’s paper said about him. Avenarius is mentioned only once, still alongside Mach, in Woodward and Ash (1982). There is no trace of Avenarius’ name in Mischel (1970), nor in Kardas (2013). Since the list of studies neglecting Avenarius could extend much further, let us concentrate on the few exceptions to this state of affairs. David K. Robinson (1987) reconstructs the relationship between Avenarius and Wundt from archival sources. Yet, being a historian, he does not focus on the philosophical discussion between the two. Katherine Arens (1989) has the merit of talking about Avenarius by making direct reference to his words. Nonetheless, she only focuses on Avenarius’ psychophysical theory, presented in the Kritik der reinen Erfahrung (Critique of Pure Experience), leaving aside his more philosophical works, such as Der menschliche Weltbegriff (The Human Concept of the World) and the Bemerkungen zum Begriff des Gegenstandes der Psychologie (Remarks on the Concept of object of Psychology). Not entirely convincing is also Arens’ choice to place Avenarius between Fechner and Wundt, not only because he was actually a follower of Wundt, at least at frst, but also because his mature view on psychology can be considered more advanced than the Wundtian one. For this reason, as we hope to demonstrate with this book, it is diffcult to agree with Arens’ statement that “the work of Wilhelm Wundt represented the major trend in academic psychology which aided to obscure the systemic analysis proposed by Avenarius” (Arens 1989, 120). Annette Mülberger (2012) deals with the confict between Avenarius’ and Wundt’s concepts of psychology, but only indirectly, since she analyzes the work of Avenarius’ pupil Rudolf Willy (1899), who had no signifcant impact on the debate of the time. Lastly, the great reconstruction of Wundt’s intellectual career by Saulo de Freitas Araujo (2015) crosses Avenarius’ path when it comes to the analysis of Wundt’s articles Über naiven und kritischen Realismus (on Naïve and Critical Realism), directed against the immanentism of Wilhelm Schuppe and Robert von Schubert-Soldern, and the Empiriocriticism of Avenarius and Mach. However, given the purpose of Araujo’s book, Avenarius is only watched through Wundt’s eyes.
closely tied to Wundt (unlike Mach, who had practically no relationship with him),12 and because—contrary to all other protagonists of Wundt’s circle—he was a philosopher interested in experimental psychology, rather than the reverse. For these reasons, Avenarius had a vantage point in the promotion of scientifc psychology within the faculties of philosophy. By the same token, he was more exposed to Wundt’s accusation against the representatives of the “new psychology:” the accusation of supporting a materialistic—and therefore philosophical and metaphysical—stand, rather than a rigorously scientifc one.
This book will show: (1) that at the beginning Wundt and Avenarius shared the same idea of psychology, thus fnding an ally in each other; (2) that, over the course of time, they parted ways, as Wundt took more conservative positions, whereas Avenarius developed a philosophical foundation for a radically physiological psychology; (3) that, at the turn of the century, the two thinkers represented two alternative paradigms for psychology: the declining Wundtian one and the rising Avenariusian one.
To meet these goals, Chapters 2 and 3 will present the conceptions, respectively, of Avenarius and Wundt. Chapter 4 will introduce some leading fgures of the second generation of experimental psychologists, showing how their departure from Wundtian positions was infuenced by Avenarius’ thought. Finally, Chapter 5 will examine Wundt’s attempt to respond to the new trend. To this end, we will pay particular attention to the chronology of the works that form Wundt’s corpus, and to the changes occurred in their different editions. By doing so, we will see that many notions that are now generally regarded as typical of Wundt’s system of thought (such as “immediate experience” or “creative synthesis”) were not part of the Wundtian orthodoxy against which the representatives of the “new psychology” were fghting. Rather, these notions were the result of Wundt’s late efforts to adjust his ideas to respond to the new trend.
Alongside a historically careful reconstruction of the debate between Wundt and his pupils, we also aim at providing a deeper analysis of the
12 The only evidence of a correspondence between the two is a telegram Mach sent to Wundt for his 70th birthday (Mach to Wundt, August 16, 1902, Wundt Archive, NA Wundt/III/1601-1700/1601/135/355-356). on the other hand, we have almost ffty letters left from the correspondence between Wundt and Avenarius (see Wundt Archive and Avenarius Archive).
philosophical content of this debate, thus avoiding the stereotyped representations of its protagonists’ positions.
In summary, the reader will fnd in these pages: (1) an exposition of Wundt’s ideas and of the way they evolved in response to the changing cultural environment; (2) a unique introduction to the philosophy of Richard Avenarius, that flls the surprising lack of studies on his thought and gives him back his own philosophical identity; (3) a more accurate account of a turning point in the history of psychology, which updates the canonical but partial reconstruction of the “repudiation of Wundt” provided by Kurt Danziger in his milestone essay from 1979; (4) an overview of some of the main protagonists and topics of the philosophical debate on scientifc psychology of the late 19th and early 20th century.
references
Avenarius Archive, Staatsbibliothek zu Berlin—Preußischer Kulturbesitz, Handschriftenabteilung.
Wundt Archive, Psychologischen Instituts der Universität Leipzig— Universitätsarchiv Leipzig. http://home.uni-leipzig.de/wundtbriefe/viewer. htm
Araujo, Saulo de Freitas. 2015. Wundt and the Philosophical Foundations of Psychology: A Reappraisal. Heidelberg: Springer.
Arens, Katherine. 1989. Structures of Knowing: Psychologies of the Nineteenth Century. Dordrecht: Springer.
———. [1891] 1905. Der menschliche Weltbegriff. Leipzig: Reisland.
Blumenthal, Arthur L. 1980. “Wilhelm Wundt: Problems of interpretation.” In Wundt Studies: A Centennial Collection, edited by Wolfgang G. Bringmann and Ryan D. Tweney, 435–45. Toronto: Hogrefe.
Boring, Edwin G. 1929. A History of Experimental Psychology. New York: Century.
Bringmann, Wolfgang G., and Ryan D. Tweney, eds. 1980. Wundt Studies: A Centennial Collection. Toronto: Hogrefe.
Carstanjen, Friedrich. 1898. “Der Empiriokritizismus: Zugleich eine Erwiderung auf W. Wundts Aufsätze ‘Über naiven und kritischen Realismus’.” Vierteljahrsschrift für wissenschaftliche Philosophie 22: 45–95, 190–214, 267–93.
Danneberg, Lutz, Andreas Kamlah, and Lothar Schäfer, eds. 1994. Hans Reichenbach und die Berliner Gruppe. Braunschweig: Vieweg.
Danziger, Kurt. 1979. “The Positivist Repudiation of Wundt.” Journal of the History of the Behavioral Sciences 15 (3): 205–30.
———. 1990. “Wilhelm Wundt and the Emergence of Experimental Psychology.” In Companion to the History of Modern Science, edited by Robert C. olby, Geoffrey N. Cantor, John R. R. Christie, and M. J. S. Hodge, 396–408. London: Routledge.
———. 2001. “The Unknown Wundt: Drive, Apperception, and Volition.” In Wilhelm Wundt in History, 95–120. Boston: Springer.
Diamond, Solomon. 2001. “Wundt before Leipzig.” In Wilhelm Wundt in History, 1–68. Boston: Springer.
Fechner, Gustav Theodor. 1860. Elemente der Psychophysik. Leipzig: Breitkopf und Härtel.
Haller, Rudolf, and Friedrich Stadler. 1993. Wien, Berlin, Prag: Der Aufstieg der wissenschaftlichen Philosophie. Wien: Hölder-Pichler-Tempsky.
Hentschel, Klaus, 1990. Die Korrespondenz Petzoldt—Reichenbach: Zur Entwicklung der “wissenschaftlichen Philosophie” in Berlin. Berlin: SIGMA.
Kardas, Edward P. 2013. History of Psychology: The Making of a Science. Boston: Cengage Learning.
Kusch, Martin. 1995. Psychologism: A Case Study in the Sociology of Philosophical Knowledge. London: Routledge.
———. 1999. Psychological Knowledge: A Social History and Philosophy. London: Routledge.
Lenin, Vladimir I. 1927. Materialism and Empirio-Criticism. Edited by Alexender Trachtenberg. Vol. XIII. Collected Works of V. I. Lenin. London: Martin Lawrence.
Milkov, Nikolay, and Volker Peckhaus, eds. 2013. The Berlin Group and the Philosophy of Logical Empiricism. Dordrecht: Springer.
Mischel, Theodore. 1970. “Wundt and the Conceptual Foundations of Psychology.” Philosophy and Phenomenological Research 31 (1): 1–26.
Mülberger, Annette. 2012. “Wundt Contested: The First Crisis Declaration in Psychology.” Studies in History and Philosophy of Biological and Biomedical Sciences 43 (2): 434–44.
Perry, Ralph B., ed. 1935. The Thought and Character of William James. Vol II. Philosophy and Psychology. London: oxford University Press.
Rieber, Robert, ed. 1980. Wilhelm Wundt and the Making of a Scientifc Psychology. New York: Plenum Press.
Rieber, Robert, and David Robinson, eds. 2001. Wilhelm Wundt in History: The Making of a Scientifc Psychology. New York: Kluwer Academic/Plenum Publishers.
Robinson, David K. 1987. “Wilhelm Wundt and the Establishment of Experimental Psychology, 1875–1914: The Context of a New Field of Scientifc Research”. PhD dissertation‚ University of California, Berkeley. ———. 2001. “Reaction-Time Experiments in Wundt’s Institute and Beyond.” In Wilhelm Wundt in History, 161–204. Boston: Springer. Tinker, Miles A. 1932. “Wundt’s Doctorate Students and Their Theses 1875–1920.” The American Journal of Psychology 44 (4): 630–37. Willy, Rudolf. 1899. Die Krisis in der Psychologie. Leipzig: o. R. Reisland.
Woodward, William Ray, and Mitchell G. Ash, eds. 1982. The Problematic Science: Psychology in Nineteenth-Century Thought. New York: Praeger.
———. 1904. Principles of Physiological Psychology. Translated by Edward B. Titchener. New York: Macmillan.
CHAPTER 2
Richard Avenarius
2.1 AvenArius’ relAtionshiP with wundt
Richard Avenarius was born in Paris in 1843, son of the publisher Eduard and brother of the poet Ferdinand, who founded the important journal Der Kunstwart (1887). The name Richard was chosen to honor his maternal uncle and godfather, the composer Richard Wagner.1 Being raised in such a stimulating environment, Avenarius grew without focusing on a single interest. He spent his early life traveling through Italy, and studying philology, psychology, and philosophy in Leipzig, Zurich, Berlin, and Munich (where he lived with his uncle, Wagner). In the years spent at these German universities, Avenarius encountered several fgures that were crucial for the shaping of his philosophy, such as the philologist Friedrich Zarncke, the Herbartian Heymann Steinthal, the logician and philosopher Moritz Drobisch, the physiologist Carl Ludwig, the already mentioned Fechner, and the zoologist Karl Semper, who also became his brother in law. In 1866, Avenarius settled down in Leipzig, where he soon revealed an inclination for organizing cultural initiatives. He took part to the then rising student movement for university reform,
1 Extended biographical information on Richard Avenarius can be found in the family history written by another of his brother (Avenarius 1912, 123–150).
C. Russo Krauss, Wundt, Avenarius, and Scientifc Psychology, https://doi.org/10.1007/978-3-030-12637-7_2
and he founded the Akademisch-Philosophische Verein (AcademicPhilosophical Society, 1866–1900), that actively involved prominent thinkers like Hans Vaihinger and Paul Barth.2
Two years later, after obtaining his doctorate with a study on Spinoza (Avenarius 1868), a new period of wandering began, between Berlin, Dresden, and Würzburg. Eventually, once again Avenarius came back to Leipzig, where on october 29, 1875, he defended his habilitation thesis: Philosophie als Denken der Welt gemäss dem Princip des kleinsten Kraftmasses. Prolegomena zu einer Kritik der reinen Erfahrung (Philosophy as thinking of the world in accordance with the principle of the least amount of energy: prolegomena to a critique of pure experience, published in 1876). In the habilitation board sat Moritz Drobisch, Max Heinze and, precisely, Wilhelm Wundt. It was probably on that occasion that Avenarius contacted him. At that time, Wundt was just arrived in Leipzig as professor of philosophy, after a career as psychophysiologist, which only granted him “scant professional recognition” (Diamond 2001, 56).
The 43-year-old Wundt and the 32-year-old Avenarius began to collaborate forthwith. The two lectured together on November 1, 1875, at the aforementioned Akademisch-Philosophische Verein.3 When Avenarius founded the Vierteljahrsschrift für wissenschaftlichen Philosophie (Quarterly for scientifc philosophy) in 1877, he engaged Wundt in the project, whose star was then rising, after the publication of the Grundzüge. Since the frst issue, the journal was published “with the participation” of Wundt, of the already mentioned Heinze, and of Carl Göring (who died only two years later, though). Wundt not only helped Avenarius running the periodical, but he also wrote some articles for its frst issues.4 It is worth noting that Avenarius repeatedly tried
2 The two thinkers mention the Leipzig Society in their autobiographical essays (Barth 1921; Vaihinger 1921). Thanks to Vaihinger we have a brief report of the activities of the Society (Vaihinger 1875). Vaihinger also talks about Avenarius’ infuence on his formation. Not only Avenarius introduced him to the work of Steinthal, that became “one of the founding basis of [Vaihinger’s] philosophical outlook;” with his “sharp criticism of Kant’s position” Avenarius also prevented Vaihinger “from turning Kantian philosophy into a dogma” (Vaihinger 1921, 190).
3 Protokollbuch des Akademisch-philosophischen Vereins zu Leipzig, Universitätsbibliothek der Karl-Marx-Universität Leipzig, Abteilung für Handschriften und Inkunabeln, MS01304.
4 For more information on these writings, see Wundt’s bibliography of those years in Robinson (2001a, 275–78).
to involve Ernst Mach too in the editorial board. Yet he received nothing but refusals from him.5 It was only after Avenarius’ death in 1896 that the Austrian physicist accepted to collaborate with the journal, when its direction was briefy taken over by two Avenarius’ pupils (Friedrich Carstanjen and oskar Krebs) before passing to Paul Barth.
In the same year of the foundation of the journal, Avenarius became professor of Inductive Philosophy at Zurich University. We can assume that Wundt’s backing was crucial for this appointment. In fact, Wundt had held that same position before his call to Leipzig, being replaced for a short period of time by Wilhelm Windelband, before Avenarius’ call. Signifcantly, Avenarius wrote to Wundt at his arrival in Switzerland, thanking him for “all the friendliness and support shown in Leipzig” and revealing “with discretion” some maneuvers attempted against his designation, that were disclosed to him by Windelband.6
Avenarius’ mission as a professor of philosophy was fully in line with Wundt’s academic policy. The latter aimed at “gaining a secure if limited place for experimental psychology” inside the faculty of philosophy, “while also demonstrating his own worthiness to ‘belong’ to philosophy proper” (Ash 1980, 264). Despite his lack of frst-hand experience in psychophysical research, throughout his career, Avenarius choose experimental psychology as the central topic of his class. In addition, he also lectured on more philosophical subjects, such as Schopenhauer, Spinoza, and Leibniz.7
This psychological—and therefore Wundtian—interpretation of the chair of philosophy was also theorized in Avenarius’ early writings, published in the frst issues of the Vierteljahrsschrift. According to him, philosophy deals with the totality of being. Still, given the impossibility to fulfll this task, it changed his key question from “What is the world?” to “How is the world thought?” (Avenarius 1877a, 472, 480, emphasis mine). Consequently, psychology—as the science of the “thinking man”—is no longer “peripheral” to philosophy. Rather, it now occupies
5 Cf. Avenarius’ letter to Mach, February 22, 1895 (Thiele 1968, 289–90).
6 Cf. Avenarius to Wundt, May 5, 1877 (Avenarius Archive, box 12; also in Wundt Archive, NA Wundt/III/1001-1100/1015/53-56).
7 Avenarius Archive, boxes 3, 16. Avenarius’ archive contains a huge folder with his notes for the main class, that he continued to update, year after year, to keep pace with the constant innovation in experimental psychology.
the “center of our ideal scientifc system” (Avenarius 1877a, 487). As a result, modern age witnesses a progressive convergence of psychology and philosophy, which share the common goal of understanding how humans think of the world.
This confuence of philosophy with science—and psychology in particular—is deemed necessary for the coming of the scientifc philosophy that Avenarius’ journal planned to promote (as stated by its very title). According to Avenarius, “scientifc philosophy” is a “philosophy that is not only formally, but also essentially science, namely because of the empirical character of its objects” (Avenarius 1877b, 7, emphasis mine). Yet, what distinguishes the new scientifc and empirical philosophy from the old-fashioned “empiricism” is the fact that the latter “stands prior to, or aside from the latest psychological advances of Steinthal, Geiger, Wundt, et al.” (Avenarius 1877–1879, 71).
These two points—the merging of philosophy and psychology, and the demand for an empirical, scientifc philosophy—also appeared in Wundt’s coeval works. In his inaugural speech at Zurich, he affrmed that philosophy “must take the whole extent of experience as its foundation” (Wundt [1874] 1906, 21). This empirical ground appears divided into two felds: one of the natural sciences (Naturwissenschaften), driven by the causal principle, and one of the so-called spiritual sciences (Geisteswissenschaften), governed by fnality. Therefore, the main task of philosophy is to resolve this opposition. Nevertheless, while everybody was expecting “a solution from a philosophical, conceptual analysis,” a “new science, until now included under philosophy, has developed,” a science that “with all its being seems appointed to mediate between natural and spiritual sciences,” namely experimental psychology (Wundt [1874] 1906, 5–6).
For Wundt, philosophy and psychology thus share the same feld (experience) and task (holding together the two sides of this feld, nature and spirit). The two disciplines are not distinguished by their methods either, since philosophy does not have a peculiar way of understanding.
It is a false excuse […] saying that there are two different ways of recognizing objects: the common one, used by individual sciences, and a special, higher one, only philosophy can soar to. (Wundt [1874] 1906, 20)
Philosophy does not stand above all other sciences. on the contrary, it has to maintain an ongoing dialogue with them, building on their results. only in this way it can become a scientifc philosophy.8
Taking into account the similarities between the two, it is clear why in the ’70s Wundt and Avenarius acknowledged one another as allies in the promotion of scientifc psychology and philosophy, and of the merging of these disciplines. They designed the Vierteljahrsschrift as a mean to take these ideas forward, sat in its editorial board and contributed to its frst issues with several papers. In an overview of contemporary German philosophy for the beneft of English readers, after summarizing the main characters of the time (young Avenarius included), Wundt signifcantly cited the Vierteljahrsschrift as a sign of the coming of a new era for philosophy:
The recent foundation of a journal (edited by Dr. R. Avenarius) with the advancement of “Scientifc Philosophy” for its aim, shows plainly that the time is passed when philosophy can hope to live apart from the other sciences. We see accordingly, at the present time, all interest turned on those two departments of philosophy that are of most account for the building up of a universal science, namely Psychology and the Theory of Cognition. […] The philosophical movement in Germany presents everywhere the spectacle of preparation for a step to be taken. New weapons are being sought in the arsenal of experience and of the human mind wherewith to carry on the old struggle round the eternal problems of thought and existence”. (Wundt 1877, 518)
However, when Wundt fame grew, as well as the number of grad students under his tutoring, the Vierteljahrsschrift became too tight for the large scientifc production of his academic circle. In 1880 Wundt’s pupil Emil Kraepelin suggested the foundation of a purely psychological journal, to house the results of Leipzig laboratory. In response, Avenarius proposed to publish the doctoral theses of Wundt’s students as supplements to the Vierteljahrsschrift. Meaningfully, even though Wundt followed Kraepelin idea, and founded the Philosophischen Studien, he did not terminate his cooperation with Avenarius’ journal. He stuck with this
8 Wundt further developed his ideas on scientifc philosophy in the Introduction of his System der Philosophie (System of philosophy, Wundt 1889, 21–23).
decision even in spite of the demand that came from the publisher of the new periodical, Rudolf Engelmann, who explicitly requested such gesture for “the interest of our journal.”9
Wundt’s and Avenarius’ plan for the promotion of the dialogue between philosophy and psychology was not limited to the foundation of a journal. Their academic policy program aimed at securing more positions for the experimental psychologists in the faculties of philosophy. We must remember that, at the time, experimental psychology did not have an institutional placement inside the universities. Psychophysical experiments were conducted by professors from the departments of medicine (e.g., du Bois-Reymond, Helmholtz) or of physics (e.g., Fechner).
Wundt’s call at Zurich and Leipzig in 1875 and 1876 represented the frst cases in which an experimental psychologist was appointed a professorship in philosophy, resulting in protests among the traditional philosophers (see Ash 1980; Kusch 1991). In this context, Avenarius’ position was quite unique, since he was one of the few, if not the only philosopher by training that was eager to open doors to experimental psychology. In light of this, it is obvious why Wundt supported Avenarius’ call at Zurich: having a proper philosopher lecturing on experimental psychology (as Avenarius did at the Swiss university) was a good argument for the legitimacy of psychology in the philosophical departments.
Given the above, it is then no surprise that Avenarius was regarded as a full-fedged Wundtian by contemporaries. He himself, in a letter to Wundt from 1883, refers that his potential call to Giessen was obstructed by “unpleasant prejudice against ‘Wundtian-oriented philosophers’,” like him.10
2.2 the critique of introjection
After his habilitation thesis and the aforementioned articles published in the Vierteljahrsschritft, Avenarius took a break of almost ten years from publishing, to develop his system of thought. This period ended when the two volumes of the Kritik der reinen Erfahrung (Critique of pure experience, 1888–1890) came out, promptly followed by Der menschliche Weltbegriff (The human concept of the world 1891) and the series
9 Engelmann to Wundt, June 6, 1881 (Wundt Archive, NA Wundt/III/16011700/1681/1/1-8). on the subject see also Robinson (1987).
10 Avenarius to Wundt, February 2, 1883 (Avenarius Archive, box 12; Wundt Archive, NA Wundt/III/1001-1100/1023/85-88).
of articles Bemerkungen über den Begriff des Gegenstandes der Psychologie (Remarks on the concept of object of psychology 1894–1895). These three works presented, from different angles, Avenarius’ view on the relationships between psychology, physiology, and philosophy. A view that immediately became part of the debate on the epistemological status of scientifc psychology. Therefore, these latter are the works we must consider to understand Avenarius’ impact on the culture of the time. For this reason, our account of Avenarius’ philosophy differs from the traditional ones, which overestimate his early works in the attempt to bring together Avenarius and Mach. In fact, it is only in his early works that Avenarius discusses the economic function of knowledge, which, on the other hand, is and has always been one of the main topics of Mach’s thought.
The starting point of Avenarius’ mature philosophy is “what is found” (das Vorgefundene), meaning the experience as the domain in which everything is given. In fact, either something is found as a part of our experience, or it is not given at all. The original, natural content of this experience is the following: “I, with all my thoughts and feelings, fnd myself amid an environment” (Avenarius [1891] 1905, 4). This means that the main constituents of experience are: me, and the environment. However, even though these two are different regions of the experience, this does not imply that they are experienced differently (Avenarius [1891] 1905, 82). They are not distinguished because the I is the one who experiences, whereas the environment is what is experienced. The I is neither a privileged, more immediate or proximate experience, nor the one who makes the experience.
To the environment “belong my fellow-men too,” which “are beings like myself” (Avenarius [1891] 1905, 4–5). The presence of other men raises a question, though: if everything must be given as a part of my experience, and if fellow-men are beings like me, and therefore have their own experiences, how can their experiences be part of my experience?
Avenarius believes that there are two possible answers to this question. His answer is that the experiences of other persons are expressed in the meanings of their movements (gestures, sounds, etc.), that is to say, in their “assertions” (also called “E-values,” or simply “E,” by Avenarius).11
11 “We designate with E every value open to description, insofar it is assumed as a content of an assertion of another human individual” (Avenarius 1888, 15).
The other possible answer consists in the so-called introjection, namely the idea that the experience of others is somehow placed inside them. According to introjection, the meaning of the assertions of others concerns what is happening in their inner sphere.
In Avenarius’ thought, introjection represents the original sin of philosophy, the “Urverdoppelung,” i.e., the source of all “duplications” that alters the natural experience (Avenarius [1891] 1905, 41). As soon as the introjection sets in, I no longer deal with a single experience, since—besides mine—there are also other experiences. Moreover, once I am accustomed to considering the experience of others as something located in their inner being, on the basis of the similarity between them and me I begin to treat my experience too in the same way. Thus, the unitary, natural experience is broken in two: the outer world, and the inner world. As a result, philosophy fnds itself bogged down in a proliferation of juxtapositions (subject and object, matter and spirit, thingin-itself and phenomenon, reality and consciousness, etc.), unable to explain their mutual relationships. Behind all this lurks the introjection, that turns the “I” from a content of experience, into the one who has the experience.
Since language is the root from which introjection stems, language is also key to defuse the outbreak of the philosophical problems (an argument that recalls the future critique of language by the neopositivists).
Thanks to the language, we can escape both the “‘realistic’ Charybdis of the ‘trespassing from consciousness’” and the “‘idealistic’ Scylla of ‘Solipsism’” (Avenarius 1890, 247).
on the one side, we have dualistic realism, that believes in an external world affecting the inner world, thus causing the experience in ourselves. This position is unable to explain how such different realms can interact with one another, and how can we grasp this outer reality. on the other side, we have monistic idealism, that posits consciousness as the only reality we can deal with. From this perspective we cannot go beyond consciousness to reveal upon what it depends, since we are eternally confned inside our minds.
In the years we are talking about, the contradiction between these two conceptions became particularly evident due to the latest developments of philosophy and psychology. As noticed by Avenarius, while philosophy, thanks to idealism, discovered the “immediate givenness of consciousness,”
psychology has to treat consciousness as a “psychological concept,” that is to say as a phenomenon that—far from being immediate—is the ultimate outcome of a complex interaction between brain and environment (cf. Avenarius [1891] 1905, X).
As anticipated, for Avenarius language represents a way out from this antinomy, insofar as it gives access to a peculiar kind of experience: that of my fellow-men. In fact, unlike mine, their experiences (as long as they are not introjected, but correctly regarded simply as assertions) have a double advantage: they are a part of my experience, rather than of a supposedly unexperienceable inner realm; but they can also be subjected to a psychophysical analysis without improperly leading beyond experience.
An example may illustrate this. When I say that my own experience-tree depends on the object-tree affecting my brain, the objecttree and the brain cannot be contents of my experience. If that were the case, we would immediately face two problems (1) The object-tree and the experience-tree (that should be caused by the former) would be the exact same thing, since in my experience there is no such thing as a distinction between an object and my experience of it. This means that the experienced object would be the cause of itself. But this is absurd (2) Similarly, if my brain is the condition of every experience but also—in its turn—an experience, it follows that the whole depends on one of its parts, and that the brain is the cause of itself. But, again, these statements are illogical.
on the other side, if the object and the brain cannot be contents of my experience, they cannot be beyond experience either, since— as already said—something which is not given in the experience is not given at all. Thus, the dependency of my experience upon an object of the environment and my brain cannot be regarded as taking place in my experience without leading to fallacies.
Contrarywise, when I say that the experience-tree of my fellow - man (i.e., his assertion of it) depends on the object-tree affecting his brain, the three components of this relationship (his asserted experience, the object-tree, and his brain) are all contents of my experience. Therefore, there is no problem in examining or stating this dependency. In other words, the connection between experience, outer objects, and brain appears as metaphysical when referring to myself
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Nitrogenous Foodstuffs or Proteins
The proteins form heat and energy when the supply of sugars, starches, and fat are exhausted, but proteins, alone form muscle, bone and sinew. They are, in this sense, the most important of foods, —they are, also, the most costly.
The foods most rich in proteins are meat and eggs. These have undergone chemical changes from the vegetable kingdom being built up into more complex compounds in the animal kingdom.
Meat and eggs are the tissue builders. In this connection it may be well to state that blood is tissue; thus meat and eggs build the blood, as well as muscle and sinew.
Nitrogenous foods, or proteins, are so called because of the large proportion of nitrogen which they contain. All nitrogenous foods contain considerable carbon—mostly in the form of fat in the meat elements—but the carbonaceous foods contain so little of the proteins that they do not appreciably enter into the nutrition,—the carbon and nitrogen in the carbo-nitrogenous foods are more equally divided.
The nitrogenous or protein elements in the body constitute about one-fifth of its weight. They make the framework, forming the basis of blood, lymph, muscle, sinew, bone, skin, cartilage, and other tissues.
Worn out body tissues is constantly being torn down and eliminated and the protein in the foods must daily furnish material for repair, as well as for building new tissue in the growing child.
A young animal’s first need is for growth, not having learned to exercise sufficiently to use much energy, and the first food given is an animal product—milk to babes and other mammals, while the young of other animals are first fed upon eggs.
The nitrogenous foods are required in smaller bulk than vegetables and fruits; they are more concentrated and contain less waste. According to recent experiments, the average adult requires from two to four ounces a day of nitrogenous foods, to repair the waste, according to the proportion of nitrogen contained. Happily, where more is consumed, the system has the power, up to a certain limit (depending upon the physical condition and the daily activity), to eliminate an excess. It is needless to say that if the daily waste is not re-supplied, the digestion and bodily nutrition suffer. The system must have the two to four ounces to supply the nitrogen daily excreted, or the tissues themselves will be consumed.
The proteins, of which meat is the principal one, are classified as Albuminoids:—albumin (white of eggs), casein (curd of milk), myosin (the basis of lean meat and gluten of wheat),
Gelatinoids, (connective tissue of meat),
Extractives (appetizing and flavoring elements).
DIGESTION
Any discussion in regard to the digestibility of foods must be general, because food which agrees with one may disagree with another, and a food which disagrees with one at a particular time may entirely agree with him at some other time; therefore, before one passes upon the adaptability of a food to the individual, it should be known that this food agrees or disagrees with him under varying conditions.
The digestibility of food depends largely upon the physical condition of the individual, because the amount of digestive juices poured into the alimentary canal is influenced by this condition, particularly by the condition of the nerves. If sufficient juices, in proper proportions, are not poured into the digestive tract, the foodstuffs are not made soluble for absorption into the blood. Digestion is practically synonymous with solution,—all solid foods must be reduced to a liquid state, through digestive juices and water, before they can pass through the walls of the stomach and intestines.
Each individual should learn to like the foods containing the nutrient elements which experience and blood tests have shown to be lacking in his case. The question of likes and of dislikes in regard to foods, is largely habit, and one can learn to like almost any food one wishes.
Where one forms the habit of discriminating too much in the food, or discarding this food or that, because at some time it has disagreed, due to the particular condition at the time, the mind approaches the table as a more or less pessimistic censor and the saliva and the gastric juices are retarded in their flow.
When one is exercising freely, so that the muscular and mucous coats of the digestive system are strong, the body will handle foods which, during sedentary habits, it would not digest. There are kinds
of foods, however, which, to certain individuals, according to the chemical composition of the body, act as actual poisons, e. g., strawberries, cheese, or coffee.
It may be well to here trace, briefly, the progress of the food through the digestive tract and the action of the juices and the ferments upon it.[3]
Salivary Digestion
The food in the mouth is mixed with saliva, which dissolves the starches, converting them into sugar. The starches are the only foods whose chemical digestion is begun in the mouth. They are first broken up into dextrin and then into the more simple sugar, known as animal starch, or maltose. Hereafter, in speaking of sugar, after it has been absorbed into the blood, the reader will bear in mind that the term refers not only to digested sugar, consumed as such, but also to digested starches (maltose), as shown on page 63.
It is important that sufficient saliva be mixed with the food, through mastication, that it may enter the stomach and there continue the chemical process of digestion of starch. If starches are not thoroughly masticated, sufficient saliva will not enter the stomach to convert the starch into sugar; the food will pass into the small intestine, which must then do more than its normal work of digestion.
The saliva consists of about ninety-nine and one-half per cent water and one-half per cent solids. The solids consist of ptyalin, sodium chlorid, sodium carbonate (baking soda), mucus, and epithelium. Ptyalin, the most important of these, is an active digestive agent; the mucus lubricates the masticated food; the sodium carbonate insures the alkalinity of the food; the salt is present in all secretions; and the water dissolves the food that the juices may more readily reach and act upon each particle.
The saliva flows into the mouth, more or less, at all times, but more copiously during mastication. Its evident purpose, when food is
not present, is to keep the lining of the mouth moist.
The flow of saliva is controlled, to a great degree, by nerves which have their centers in the medulla oblongata. The sight of food, pleasingly served, or even the thought of food which one likes, will increase the salivary flow. This is one instance of the control of thought materially affecting digestion, and the importance of forming the habit of cultivating a taste for all kinds of food, is apparent. The stronger the relish for the food, and the more thoroughly it is masticated, and mixed with the saliva, the more perfect will be the first step in digestion. This first step of thorough mastication is all important, not only because the chemical action upon the starch molecules is facilitated by the thorough softening and mixing with the saliva, but thorough mastication also tends to prevent overeating.
Water encourages the flow of saliva and for this reason should be drunk copiously before meals, particularly where digestion is weak. It may also be taken at rest periods during the meal. (See page 44).
Stomach Digestion
As the food enters the stomach, the gastric juice pours out from the mucous lining, very much as the saliva pours into the mouth. It consists of ninety-nine and one-half per cent water and onehalf per cent solids, as does the saliva. The solids of the gastric juice are composed of pepsin, rennin, hydrochloric acid, and mucus. The mucus serves to lubricate the food as in the saliva. It also prevents the digestion of the mucous lining of the stomach itself.
The hydrochloric acid and the pepsin cause the principal chemical changes in the food while in the stomach, acting alone upon the proteins. The only digestion of starches in the stomach is that continued by the saliva. The salivary digestion proceeds until the gastric juice is secreted in sufficient quantity to cause a marked acidity of the stomach contents, when the starches are passed into the intestines.
Gastric juice begins to flow into the stomach soon after eating, but it is not secreted in sufficient quantity to supersede salivary digestion for from twenty to forty-five minutes.
The result of gastric digestion of proteins is their conversion, first, into albumin, then into proteosis and, lastly, into peptone, which is protein in a more simple, soluble, and diffusible form. In the form of peptone, the proteins are in condition to be absorbed.
If the food has been properly cooked and masticated the gastric digestion will be completed in one and one-half to three hours. If not properly cooked and masticated, the stomach digestion may continue one to two hours longer. It should, however, be completed in three hours.
The most readily digested animal foods remain less time in the stomach. Meat, as a rule, is easily digested, because the action of the digestive juices of the animal has converted the starches and sugars. The white meat of chicken, being soft, is digested in a shorter time than the red or the dark meat.
Fluids leave the stomach more rapidly than solids. Seven ounces of water leave the stomach in one and one-half hours, seven ounces of boiled milk in about two hours.
The flow of gastric juice, as the flow of saliva, is governed by the nerves;—the sight, taste, and smell of food, and the attitude of mind toward it, to a certain extent, regulates its flow.
After the food has extensively accumulated, during the progress of a meal, the stomach begins a series of wave-like movements called peristaltic waves.[4] These waves work downward through the length of the stomach towards its lower opening, known as the pyloric orifice. As the food is moved down the stomach by these motions, it is thoroughly mixed with the gastric juice.
During the early stages of digestion, the sphincter muscles of the pylorus keep the lower end of the stomach closed, but, as digestion progresses, the pylorus gradually relaxes to let the digested, soluble portion of the food pass into the intestine. If the food still remains in a solid form, by reason of being improperly cooked or poorly
masticated, as it touches the pylorus, these sphincter muscles, almost as if they were endowed with reasoning faculties, close, forcing the undigested mass back to be further acted upon by the gastric juice,—the solid mass is not allowed to pass until dissolved.
If the individual continues to abuse the stomach and to cause it to work overtime, it becomes exhausted and demands rest; it refuses to discharge the gastric juice in proper proportion; the peristaltic movements are weak; and food is not promptly or forcefully moved along the stomach and mixed with the gastric juice. This demand for a rest is termed Indigestion.
To sum up,—digested sugar is dextrose; digested starch is first dextrin, then maltose (animal, sugar); digested protein is peptone; and, digested fat is saponified fat.
Intestinal Digestion
The food passes from the stomach, through the pylorus into the small intestine. The first twelve inches of the small intestine is known as the duodenum. In the duodenum it is acted upon by the pancreatic juice from the pancreas, the bile from the liver, and the intestinal juices. These juices act upon proteins, fats, and carbohydrates. The bile acts upon the fats, while the pancreatic and intestinal juices act chiefly upon the carbohydrates.
As the food enters the intestine, it is changed, by the sodium carbonate, from the acid condition produced in the stomach, to alkaline reaction.
The bile exercises an important influence upon digestion, any disturbance in the flow of this greenish-brown secretion being very quickly shown both in stomach and intestinal digestion. It emulsonizes and saponifies the fats, it aids in their absorption, and it lubricates the intestinal mass, facilitating its passage through the entire length of the intestines. Thus, it is a very potent agent in regulating the bowel movements. A diminution in the flow of bile quickly expresses itself in constipation.
Fats are almost entirely digested in the small intestine. The presence of fat stimulates the flow of pancreatic juice, which, in turn, stimulates the flow of bile from the liver. For this reason, if the liver is sluggish, fatty foods are desirable. Olive oil is prescribed for gall stones to stimulate the action of the bile ducts.
Before the fat molecules can be absorbed, they must first be broken up into glycerin and fatty acids and further changed to a fine emulsion, which gives the contents of the small intestine a milky appearance. After they are broken up into these fatty acids and thus brought to the finest state of emulsion, they are readily saponified, being then soluble in water and in a state to be absorbed by the walls of the intestines. The fats are absorbed almost entirely in the small intestine,—mostly in the duodenum.
As a rule, the starches, or dextrin, will not be fully digested by the saliva and those which have failed of salivary digestion are acted upon by amylase (one of the solids of the intestinal juice) and changed to maltose, while the trypsin from the pancreas, together with the intestinal juice, acts upon any protein which has failed to be fully digested in the stomach, changing it into peptone. In the form or peptone it is absorbed through the “sucking” villi of the intestinal walls.
The food is forced along the intestinal tract by peristaltic or muscular relaxation and contraction waves, as in the stomach. As it is so forced, the nutrient elements, after being put into condition for absorption, are taken up through the villi of the intestinal walls by the portal veins and the lacteals of the sub-mucous lining. (See page 78).
It is now believed that a larger proportion of food is digested and absorbed than was heretofore realized, and that the excretions from the intestines are, in many cases, made up almost entirely of refuse, and of the catabolic waste of the system. In an ordinary, mixed diet, it is stated that about ninety-two per cent of the proteins, ninety-five per cent of the fats, and ninety-seven per cent of the carbohydrates are retained by the body.
In digestion, it is of the utmost importance that the muscular, mucous, and the sub-mucous coats, and the secreting glands of the stomach and intestines be kept thoroughly strong and active, that the digestive juices may be freely poured out, the nutriment be freely absorbed, and the food be moved along the digestive tract. The strength of any organ is gained through the nutriment in the blood; therefore, daily exercise, which calls the blood freely to these organs, is imperative.
Absorption of Food
The greater part of the food is absorbed through the intestines, yet some proteins, which have been fully digested by the gastric juice, and certain fats, particularly the fats in milk, which are in a natural state of emulsion, may be absorbed through the walls of the stomach. However, the absorption through the stomach is small compared to that through the intestines.
The small intestine is particularly fitted for absorption. Every inch or so along its course the mucous lining is thrown up into folds, as if to catch the food as it passes toward the large intestine, and to hold it there until the villi have the opportunity to absorb it. These transverse folds of the intestinal walls are called valvulæ conniventes. The villi are fingerlike projections of the mucous lining of the intestines, which stand out upon the lining somewhat as the nap on plush. They have been called “sucking” villi, because during the movements of the intestines they seem to suck in the liquid food. As soon as the foodstuffs,—proteins, carbohydrates, and fats, are put in a dissoluble state ready for absorption, they are very promptly absorbed by the villi. If, for any reason, they remain unabsorbed, they are liable to ferment by the action of the trypsin, or to be attacked by the bacteria always present in the intestines.
The peptones, sugars, and saponified fats are rapidly absorbed, while the undigested portion, together with the unabsorbed water, the bile, mucus and bacterial products, are passed through the ileocecal valve into the large intestine.
That the large intestine is also adapted to the absorption of fats is shown by clinical experiments with patients who cannot retain food in the stomach, the food in such cases being given through rectal injections.
In the large intestine, the mass passes up the ascending colon, across the transverse colon, and down the descending colon, losing, by absorption, foodstuffs not absorbed in the stomach and small intestine.
While water and salt are absorbed both in the stomach and in the small intestine, the evident purpose in leaving the larger part of the water to be absorbed in the large intestine is that it may assist the intestinal contents in passing along. The water also stimulates the peristaltic movement.
As the food is absorbed through the walls of the alimentary canal, it is picked up by the rootlets of the mesenteric veins[5] and by the lymph channels,—the latter, through the abdominal cavity, are called lacteals. Nearly all of the fats are absorbed through the lacteals. The whitish color given to the contents of the lacteals, by the saponified fats, gives rise to the term lacteal, meaning “whitish.”
Nearly all of the proteins and sugars pass through the mesenteric veins and the portal veins into the liver. Here the sugars are at once attacked by the liver cells and built up into glycogen as described on page 81 and the proteins are passed through the liver into the arterial blood stream. A small portion of the proteins, however, do not go to the liver, but are passed directly into the lymphatics and thus into the blood stream, where they are again carried to the liver.
To sum up,—the larger part of the absorption of sugars, starches, proteins, and fats is through the small intestine, though some are absorbed in the stomach and a very little through the large intestine; while some water and salts are absorbed in the stomach and small intestine, these are largely absorbed in the large intestine.
FOOTNOTES:
[3] A knowledge of the mucous lining of the stomach and intestines, and of the tributary glands, such as the liver and pancreas, is important to a thorough understanding of digestion, and the reader is referred to “The Vital Organs: Their Use and Abuse” of this series. This takes up the study of the secretion of digestive juices, the conditions favoring normal secretions, etc.
[4] See “The Vital Organs; Their Use and Abuse” by Susanna Cocroft
[5] For illustration see the frontispiece of “The Circulation, Lungs, Heart,” of this series.
The Work of Various Organs Affecting Digestion
The purpose of this chapter is to show the work of other organs than the digestive organs in converting the digested food to use in the body, in tearing down waste, and in eliminating waste and an excess of material above the body needs.
Work of the Liver
The liver is commonly called the chemical workshop of the body. The proteins and sugars are carried through the blood (portal veins) to the liver directly they are absorbed from the alimentary canal. As the food materials filter through the blood capillaries, between the liver cells, several substances are absorbed, particularly sugar, which is here changed into animal starch called glycogen. It is held in the liver for a few hours in the form of glycogen and then redigested by the action of an amylolitic ferment and again gradually given out into the blood in the form of sugar; hence sugar is subject first to the anabolic change of being built up into glycogen, and then to the catabolic change of oxidation and breaking down.
While the conversion of the sugar is one chief office of the liver, it also acts upon the proteins,—not as they are first passed through the liver in the blood, but as they are returned to the liver from the muscle tissue, partly oxidized and broken up into simpler products. The liver cells absorb and further oxidize and combine them into nitrogenous waste, which the kidneys throw off in urea.
The liver and the spleen also break up the pigment or coloring matter of the red blood corpuscles. As they become worn out, they are retired in the liver and the spleen from the circulation. The iron is
retained by the liver cells and the remainder is thrown off from the liver, in the bile.
The liver is often called the watch dog of the body, because it is on guard for all poisons which pass through it in the blood. The large part of these toxic substances are absorbed through the alimentary canal with other foodstuffs. Many of them are the result of the fermentation of foods which are not digested as promptly as they should be, on account of an insufficient secretion of digestive juices, or a failure to secrete them in normal proportions, or due to inactivity of the stomach and intestines.
It surely is a wise provision of nature to supply a guard to oxidize, or break down these poisons and make them harmless, so that they do not pass to all parts of the body as poisons, thus affecting the nerves and the blood stream, and, through these, the entire system.
The necessity of correct habits of deep breathing will be readily seen, because oxygen is required to break down the poisons as well as to oxidize the waste of the system.
One example of the action of the liver in rendering substances harmless, is its oxidation of alcohol. From one to three ounces of alcohol a day are oxidized and made harmless in the liver, varying according to the individual and to the condition, at different times, in the same person. If the limit of one to three ounces is exceeded, the excess is not oxidized and intoxication results. These evidences of intoxication are in the nature of narcosis; alcohol is now regarded as a narcotic along with ether and chloroform.
It was formerly held by physiologists that alcohol was a food, because its oxidation liberates body heat and it was assumed that this liberation of heat, was the same as that freed by the combustion of fats, starches, and sugar uniting with oxygen. More recent knowledge, however, has unquestionably determined that heat, resulting from oxidation of alcohol, does not keep up body temperature; the pores of the skin are opened and there is a greater loss of heat through the skin. This really makes the system less able to resist cold. Large doses of alcohol actually cause a fall in body temperature and every force of the body is decreased in efficiency,
while if alcohol were an actual food the efficiency would be increased. We are forced to the conclusion, therefore, that alcohol is a pseudo-food as it is a pseudo-stimulant.
Work of the Muscles
The muscles play an important part in the use of foods. Most of the heat is generated in them, by the sugar and fats coming in contact with the oxygen in the blood. This heat is liberated during every moment of the twenty-four hours, asleep or awake. Of course, more is liberated during exercise, since the movement of the muscles sets all tissues into activity and the blood circulates more strongly, bringing a greater supply of oxygen to them. It is always well during active exercise to stop frequently and fully inflate the lungs. The effort should always be made to breathe fully and deeply —otherwise the pressure of the liberated carbon dioxid will cause a pressure throughout the blood stream, particularly about the heart and in the head. This pressure is relieved when the excess of carbonic acid gas liberated has been thrown off by the lungs. Nature makes the effort to throw off the excess of carbonic acid gas by forcing one to breathe more rapidly while running or taking unusual exercise.
The oxidation changes are simply a combustion of sugars and fats, liberating latent heat as they are brought into contact with the oxygen. Exercise and a regulation of the amount of carbohydrates and fats consumed in the foods is the natural, scientific method for the reduction of an excess of fat.
A certain amount of protein is constantly oxidized in the muscles, also, being broken down into carbon dioxid, water and a number of nitrogenous mid-products. The carbonic acid gas and water are thrown off by the lungs and the partially oxidized, nitrogenous waste is carried to the liver, where it is further oxidized and prepared for excretion, through the kidneys, lungs, skin and intestines.
When sugar is carried to the muscles in larger quantities than can be utilized by them, it is often built up into animal starch and stored in the form of glycogen, similar to its chemical change and storage in the liver.
This storage of glycogen in the muscles and in the liver is a wise provision of Nature. It is a reserve to be called upon whenever the expenditure of heat and energy exceeds the amount supplied in any day’s rations.
Work of the Nerves
The nerves oxidize food materials, but not to any great extent, excepting during nervous activity During periods of rest, food materials are stored in the nerve cells in grandular form. They represent concentrated nerve foods and are the result of anabolic processes. During nervous activity they are oxidized and carried away through the blood and the lymph. This oxidation of the food, stored in the nerves, creates nervous energy and heat.
The energy liberated by the nerves resembles electrical energy
Where one subjects himself continuously to an excess of nervous activity, all reserve food material, stored in the nerve cells, is used and the result is a trying nerve tension. Such individuals need plenty of easily digested food.
Work of the Lungs
The lungs absorb oxygen and eliminate carbon dioxid. They occasionally throw off a very little organic material.
The carbon dioxid is carried to the lungs from the tissues through the venous stream and diffused through the capillary walls of the lungs. The oxygen is absorbed into the capillaries through the thin air sacs in the walls of the lungs.
Work of the Kidneys
The kidneys do not absorb as do the lungs, neither do they perform any anabolic work as does the liver, nor catabolic work as the muscles, nerves and the liver. They simply throw off waste matter
The blood passes through them in a transverse branch from the abdominal aorta. In its circuit urea, uric acid, urates, sulphuric acid, sulphates and sodium phosphates pass from the blood with the water and are thrown from the system; hence the kidneys are purifying organs, as are the lungs. The blood returning from the kidneys through the veins is pure, just as the blood in the pulmonary vein is pure, while that in the arteries to the kidneys and the lungs is impure.
The above substances cannot be thrown off from the lungs. They are the products of oxidation of proteins, partly of the living tissues and partly those broken down direct as they are supplied in the foods, in excess of the needs of the system.
Interference in the action of the kidneys results in a hoarding of these substances in the blood, and may produce an intoxicated condition known as uremic poisoning.
Water in abundance and diuretic fruits and vegetables, which increase the activity of the kidneys, should be taken where uremia is indicated. (Foods which cause a free flow of urine are called diuretic foods.)
Work of the Skin
The sweat glands also throw off an excess of water and salts. The kidneys and the skin are interdependent; if the kidneys are inactive the skin throws off a larger quantity and if the skin is inactive, or if for any reason the pores of the skin are closed, the kidneys are more active. This is evidenced by the sudden immersion of the body in cold water; the pores of the skin being closed the kidneys immediately act.
During the summer, or at any time when the skin throws off more water than usual, the kidneys are less active and the urine, being more concentrated, is darker.
The skin also throws off carbon dioxid and, to a slight extent, it absorbs oxygen.
Work of the Intestines
The intestines, in their work of elimination, pass off all undigested matter. They also carry off bile pigment, bile salts, mucus, amino acids, and other decomposition of proteins,—also a little unabsorbed fats and bacterial decomposition taking place in the intestines. Coarse articles of food containing fibres which do not digest, such as the bran of grains and the coarser fruits and vegetables (though much of their substances are not food in the strictest sense) are valuable to increase the peristaltic movements of the intestines and to act as a carrying body to move the waste excretions along their course.
The combustion, or burning of fuel in any form, (oxidation for the release of latent heat and energy) always leaves some parts which are not used as heat or energy, and it is the work of the intestines to eliminate much of this refuse. When coal is burned, gas, smoke and cinders or clinkers, constitute the waste and if these were not allowed to escape from a stove the fire would soon go out—the smoke and gas would smother it and the clinkers would prevent the circulation of oxygen and soon clog and fill the stove. The same is true in the body—the carbonic acid gas not being allowed to pass off would soon put out the fires of life; it would poison the body and stunt the action of the nerves. If the nitrogenous waste (like ashes and cinders) is not eliminated by the kidneys, one will die in convulsions in one or two days.
The absolute necessity of a free elimination of waste will be readily seen.—If the engine is to do its best work, the engineer sees that it is kept perfectly clean—otherwise it becomes clogged, does inefficient
work and the clogging soon wears out some parts. The same is true in the body,—clogging in any part overworks and wears out other parts dependent upon the work of the one.
Summary
Let us sum up the processes which the food undergoes in its conversion into condition to be absorbed by the body; in its absorption through the walls of the intestines and stomach; and the metabolic processes which it undergoes in being converted into heat and energy and again broken down and eliminated as waste.
The Saliva begins the digestion of starches and sugars in the mouth. This digestion is continued by the saliva in the stomach.
The Stomach, when in normal condition, thoroughly digests the proteins. If any proteins fail of digestion in the stomach the process is completed in the intestines.
The Intestines, aside from their work of digestion and absorption, excrete bile pigment, bile salts, animal acids, mucus and other decomposition of proteins, with bacterial fermentation and putrefactions; also such food materials as are not digested.
The small intestine digests and absorbs the fats and continues the digestion of starches, sugars and fats when this digestion is not completed in the stomach.
The large part of the food is absorbed through the small intestine, though a small part is absorbed through the walls of the stomach and through the large intestine.
Fats are almost entirely absorbed in the small intestine. They are absorbed through the lacteals and are carried into the blood stream.
The Liver. The proteins and the starches (converted into maltose) and sugars pass into the liver. The sugar (including the sugar in vegetables, milk, fruits and that used for sweetening, as well as the carbohydrates which have been changed into maltose), is converted into glycogen in the liver, stored here for a time and again broken
down into sugar that it may be in condition to be absorbed into the blood.
The proteins pass through the liver but are not acted upon by this organ until they again return to the liver through the blood stream, after they have been partly oxidized in the tissues. The liver further oxidizes them putting them into condition to be excreted by the kidneys and intestines.
The liver also breaks up the worn out red corpuscles, putting them into condition to be eliminated in the bile.
It oxidizes and renders harmless poisonous substances absorbed in the food, such as fermented food products and alcohol.
The Muscles oxidize the fats and sugars liberating the latent heat and energy.
They partly oxidize proteins which are further broken up in the liver.
The Nerves oxidize food materials stored in the nerve cells, providing nervous energy.
The Lungs absorb oxygen and throw off carbon dioxid, watery vapor and some organic substances.
The Kidneys and The Skin purify the blood by excreting water, carbon dioxid and nitrogenous waste.
