Alfred Denker

Martin Heidegger is probably the last of the great letter writers in the history of philosophy. He wrote an estimated 10,000 letters in his life. If we add to this the sheer mass of his publications and other writings—the collected edition of his writings (Gesamtausgabe) contains approximately 100 volumes—it is hard to imagine how he found time to do other things than write. During his lifetime a number of interesting letters were published. In this chapter I will present an overview of his correspondence. In the first section I will discuss his letters in general. The second section is dedicated to the letters that were published during his lifetime with his permission and correspondences that have been published since his death. In the third section we will take a closer look at the planned publication of almost all his letters in the Martin - Heidegger - Briefausgabe.


Martin Heidegger corresponded with many important philosophers (among others Heinrich Rickert, Edmund Husserl, Karl Jaspers, Karl Löwith, Hans-Georg Gadamer, Hannah Arendt, Hans Jonas, Max Scheler, Jean-Paul Sartre, and Ernst Tugendhat), scholars of the humanities (e.g. Kurt Bauch, Beda Allemann, and Emil Staiger), scientists (Werner Heisenberg and Carl-Friedrich von Weizsäcker), psychiatrists (Medard Boss and Ludwig Binswanger) theologians (Conrad Gröber, Karl Rahner, and Johannes Baptist Lotz), authors and poets (René Char, Paul Celan, and Ernst und Friedrich-Georg Jünger to name a few), and artists (for instance Eduardao Chillida, Bernhard Heiliger, Georges Braque, Otto Dix, and Hans Kock). Many of Heidegger’s correspondences and letters are voluminous. His largest correspondence with his wife Elfride contains over 1,100 letters and we have to bear in mind that several hundred letters have been destroyed. The longest letter has over 50 manuscript pages. Heidegger’s letters are first and foremost important because of their biographical and philosophical content. Heidegger often presents and clarifies his thought in his letters. Repeatedly he gives a far more detailed account of his thought than elsewhere. He is also very critical of himself and his work. And of course the letters always show glimpses of the background or context of his thought that cannot be found anywhere else. Without exaggerating we can claim that his letters are an important addition to his work and lecture courses. We could describe his correspondence as a work in its own right alongside the Gesamtausgabe.

The importance of his letters has been documented by the few published correspondences. They are unique and irreplaceable sources for any biographical, historical, or philosophical interpretation of Heidegger’s life and work. Heidegger’s correspondence with Karl Jaspers is for instance not only of great help in understanding Heidegger’s relation to the university and his ideas of a reform of the Humboldt-University but also of incomparable value for an understanding of the genesis of his main work Being and Time. His correspondence with Karl Löwith that will be published in 2013 is of similar importance. Heidegger’s correspondence with Hannah Arendt, Elisabeth Blochmann, and his wife are of great value for biographical and philosophical research. In these correspondences Heidegger shows himself in his role as philosophical mentor who not only clarifies his thought but also explains his thought in its philosophical context and against the historical background. The letters also contain numerous accounts of his travels and contacts for which we have no other sources. For the time immediately after the end of Second World War Heidegger’s correspondence with Max Müller is of utmost importance. It offers many insights into the Denazification-process, university politics, and Heidegger’s role.


Heidegger published or gave permission to publish letters during his lifetime. The most famous letter of them all is without doubt his letter to Jean Beaufret that was written in late 1946 and published in 1947 under the title “ Brief über den Humanismus [Letter on Humanism]” in a small volume that also contained his “ Platons Lehre von der Wahrheit [Plato’s Doctrine of Truth].”1 Heidegger’s letter was an answer to a letter Beaufret had written to him on November 10, 1946.2 In this letter Heidegger looked back on his path of thought from Being and Time until 1946 and positioned himself in the philosophical debate of the time. It is to a certain extent also an answer to the famous essay by Jean-Paul Sartre, “L’existentialisme est un humanisme” that was published earlier in Paris in 1946.

Another important letter is Heidegger’s letter to William J. Richardson, SJ, that was published as a “preface” in his magnus opus: Heidegger. Through phenomenology to thought.3 Heidegger’s comments on Richardson’s interpretation of his thought offers some valuable insights in the problem of the “turning” on his pathway of thought.

This is not the place to take a closer look at the contents of these letters. Instead I will provide the readers with a complete list of the letters that were published with Heidegger’s permission during his lifetime. It may be of interest to note that the last letter of this list is the last thing Heidegger wrote in his life.

Letter to Max Kommerell, published in: Max Kommerell. Briefe und Aufzeichnungen 1919–1944. Freiburg 1967, 404–5.

To a verse of Mörike. A correspondence with Martin Heidegger from Emil Staiger. In: Trivium 9, Zürich 1954; reprinted in: Martin Heidegger, Aus der Erfahrung des Denkens, hrsg. von Hermann Heidegger, Gesamtausgabe 13, Frankfurt am Main 1983, 93–109.

Martin Heidegger’s letter on Einführung in die Metaphysik. In: Die Zeit, Jhg. 8, Nr. 39. 15. September 1953. Reprinted in: Martin Heidegger, Einführung in die Metaphysik, hrsg. von Petra Jaeger Gesamtausgabe 40, Frankfurt am Main 1983, 232–3.

Letter of April 1962 to William J. Richardson, SJ, published as a preface in his Heidegger. Through phenomenology to thought. The Hague 1963, vii–xxiii.

Letter to Takehiko Kojima written July 5, 1963. In: Dino Larese (Hrsg.), Begegnung. Zeitschrift für Literatur, bildende Kunst, Musik und Wissenschaft 1, 1965, 2–7.

Letter of March 11, 1964 written for a discussion at Drew University in Madison (USA) from April 9 to April 11, 1964. Einige Hinweise auf Hauptgeschichtspunkte für das theologische Gespräch über “Das Problem eines nicht-objektivierenden Denkens und Sprechens in der heutigen Theologie,” first published in French translation in: Archives de Philosophie (32) 1969, 396–416. Reprinted in: Martin Heidegger, Wegmarken, hrsg. von Friedrich-Wilhelm von Herrmann Gesamtausgabe 9, Frankfurt am Main 1976, 68–78,

Readers letter to the editor in chief of the Spiegel of February 22, 1966. In: Der Spiegel, Jhg. 20, Nr. 7, 7. February 1966, 110–12; Nr. 11, 7. März 1966. 12. Reprinted in: Martin Heidegger, Reden und andere Zeugnisse eines Lebensweges, hrsg. von Hermann Heidegger, Gesamtausgabe 16, Frankfurt am Main 2000, 639.

Letter to Arthur H. Schrynemakers of September 20, 1966 as greetings to the Symposium on Heidegger’s Philosophy at Dusquesne University, Pittsburgh October 15–16, 1966 published in: John Sallis (ed.), Heidegger and the Path of Thinking. Pittsburgh 1970; reprinted in Gesamtausgabe 16, 650–1.

Letter to Manfred S. Frings of October 20, 1966 as greetings to the Heidegger-Symposium in Chicago, November 11–12, 1966, published in: Manfred Frings (ed.), Heidegger and the Quest for Truth. Chicago 1968; reprinted in: Gesamtausgabe 16, 684–6.

Letter to François Bondy from January 29, 1968, reprinted in: Critique. Revue générale des publications françaisses et étrangers (24), 1968.

Letter to Roger Munier from July 31, 1969. In: Qu’est-ce que la métaphysique?, précédé d’une lettre de l’auteur. Trad. Roger Munier, published in: Le Nouveau Commerce, cahier 14, été-automne 1969, 55–6; reprinted in: Martin Heidegger, Seminare, hrsg. von Curd Ochwadt, Gesamtausgabe 15, Frankfurt am Main 1983, 414–16.

Letter to Albert Borgmann from 29. October 39, 1969 as greetings and thanks to the participants of the Heidegger-Conference in Honolulu, Hawaii 17–21. November 17–21, 1969, published in: Philosophy East and West 20, 1970; reprinted in Gesamtausgabe 16, 721–2.

Letter to Jan Aler from November 1970, published in: Zeitschrift für Ästhetik und allgemeine Kunstwissenschaft 18, 1973; reprinted in: Gesamtausgabe 16, 723–4.

Letter an Henri Mongis from June 7, 1972, published in: H. Mongis. Heidegger et la Critique de la Notion de Valeur. The Hague 1976, vi–xi, reprinted in: Gesamtausgabe 16, 727–9.

Greetings to the Symposium in Beirut November 1974, in: Extasis. Cahiers de philosophie et de littérature (8), Beirut 1981; reprinted in Gesamtausgabe 19, 742–3.

Letter from November 19, 1974 as congratulations to the publishing of volume 500 of the journal Risô, published in: Risô, (500), January 1975; reprinted in: Gesamtausgabe 16, 744–5.

Greetings to Bernhard Welte and his hometown Meßkirch from late May 1976, published in: Stadt Meßkirch—Ehrenbürgerfeier Professor Dr. Bernhard Welte. Meßkirch 1978; reprinted in: Gesamtausgabe 13, 243.

In the last 25 years important correspondences have been published. The most famous correspondence is of course the letter exchange with his onetime lover Hannah Arendt. These publications have documented the different stages of Heidegger’s life and work. Some of his earliest letters—that offer insight into Heidegger’s philosophical development in his student years—were published in the Heidegger-Rickert correspondence. For the 1920s and the genesis of Being and Time the correspondences with Karl Jaspers and Karl Löwith are of great importance. Heidegger’s relation to National-Socialism in the late 1930s and early 1940s can be found in his letter exchange with Kurt Bauch. In his second letter to Bauch from March 14, 1933 for instance Heidegger writes:

In my opinion we can only try to avoid mistakes and make people conscious of the necessity of a total revolution that cannot be achieved by so-called measures alone, but only by a clarification and determination of the will and the mission of the young generation: In this respect I have already presented a proposal in the committee. If we don’t want our platonic program come to nothing, we need to know first what the government is planning.4

From this passage we can learn several things: (1) Before Heidegger became rector of Freiburg University on April 21, 1933 he had already formulated a program for a reform of the Humboldt-University. From the Heidegger-Jaspers correspondence we know that the necessity of a university reform was one of the main topics of their discussions in Heidelberg in the early 1930s. (2) He was actively trying to promote this proposal not only among the other professors but also in the Ministry of Education in both Karlsruhe and Berlin. (3) Heidegger’s reform program was inspired by Platonic philosophy. A small citation from a letter like the one above already proves that Heidegger’s involvement with National-Socialism and his ideas of university reform that he tried to put in place as rector in 1933 cannot be separated from his thought. There are not only philosophical reasons why Heidegger was attracted to National-Socialism and the charismatic leadership of Hitler but also philosophical reasons why he became ever more critical of National-Socialism. In the late 1930s he sees National-Socialism as the most extreme and terrible form of Nihilism and Hitler and his clique as the worst criminals in history.

For the convenience of the reader I have put together a list of the Heidegger correspondences that have been published so far.

Hannah Arendt/Martin Heidegger, Briefe 1925 bis 1975 und andere Zeugnisse, Frankfurt am Main: Vittorio Klostermann, 1998.

Martin Heidegger/Elisabeth Blochmann, Briefwechsel 1918–1969, Marbach am Neckar: Deutsches Literaturarchiv, 1989.

Martin Heidegger/Imma von Bodmershof, Briefwechsel 1959–1976, Stuttgart: Klett-Cotta, 2000.

Martin Heidegger/Edmund Husserl, Briefwechsel 1916–1933; in: Heidegger-Jahrbuch Bd. 6 (2012), 9–39.

Martin Heidegger/Karl Jaspers, Briefwechsel 1920–1963, Frankfurt am Main/ München; Vittorio Klostermann/Piper, 1990.

Martin Heidegger/Erhart Kästner, Briefwechsel 1953–1974, Frankfurt am Main: Insel Verlag, 1986.

Martin Heidegger/Heinrich Rickert, Briefe 1912–1933, Frankfurt am Main: Vittorio Klostermann, 2002.

Rudolf Bultmann/Martin Heidegger, Briefwechsel 1925–1975, Frankfurt am Main/Tübingen: Vittorio Klostermann/J.C.B. Mohr Verlag, 2009.

Martin Heidegger/Ludwig von Ficker, Briefwechsel 1952–1967, Stuttgart: Klett-Cotta, 2004.

Ernst Jünger/Martin Heidegger, Briefe 1949–1975, Frankfurt am Main/Stuttgart: Vittorio Klostermann/Klett-Cotta, 2008.

Martin Heidegger, Briefe an Max Müller und andere Dokumente, Freiburg/München: Karl Alber Verlag, 2003.

Martin Heidegger/Bernhard Welte, Briefe und Begegnungen, Stuttgart: Klett-Cotta, 2003.

Martin Heidegger/Kurt Bauch, Briefwechsel 1932–1975 (Martin-Heidegger-Briefausgabe II.1), Freiburg: Verlag Karl Alber, 2011.

Martin Heidegger/Erhart Kästner. Briefwechsel 1953–1974. Herausgegeben von Heinrich W. Petzet. Frankfurt am Main: Insel Verlag, 1986.

Heideggers Briefwechsel mit Max Kommerell wurde teilweise veröffentlicht in: Max Kommerell, Briefe und Aufzeichnungen: 1919–1944. Aus dem Nachlaß herausgegeben von Inge Jens. Freiburg: Olten, 1967.

Karl Löwith veröffentlichte Teile von seinem Briefwechsel mit Heidegger in: Karl Löwith, Zu Heideggers Seinsfrage: Die Natur des Menschen und die Welt der Natur; in seinen Sämtlichen Schriften. Bd. 8: Heidegger—Denker in dürftiger Zeit. Stuttgart: Metzler, 1984.

Heideggers Briefwechsel mit Paul Häberlin wurde veröffentlicht in: Paul Häberlin/ Ludwig Binswanger. Briefwechsel 1908–1960. Herausgegeben von Jeannine Luczak. Basel: Schwabe, 1997.

Heideggers Briefwechsel mit Medard Boss wurde teilweise veröffentlicht in: Martin Heidegger, Zollikoner Seminare. Protokolle—Zwiegespräche—Briefe. Herausgegeben von Medard Boss. Frankfurt am Main: Vittorio Klostermann,2 1994.


The Martin-Heidegger-Briefausgabe has been published by Verlag Karl Alber in three divisions and edited by Alfred Denker and Holger Zaborowski. Its aim is to publish Heidegger’s correspondences with philosophers, scientists, artists, writers, and other personalities as well as his private and institutional correspondence with universities, ministries, publishers, and academies. The series is divided into three divisions: I. Private correspondence, II. Scientific correspondence, and III. Correspondence with institutions and publishers. Approximately 45 volumes are planned. A full list is provided below. In 2011 the first volume of the Martin-Heidegger-Briefausgabe was published. It contains Heidegger’s correspondence with his colleague and friend, the historian of art Kurt Bauch mentioned above.

Heidegger’s letters will continue to be of utmost importance for the research into his life and thought.

Volume Correspondence Number of letters (approx.)
I.1 Correspondence with his parents and sister 126
I.2 Correspondence with his wife Elfride 1,100
I.3 Correspondence with his brother Fritz 700
I.4 Correspondence with other family members (nephews, nieces, grandchildren, parents-in-law, etc.) 300
I.5 Correspondence with his friends Bruno and Erika Leiner 200
I.6 Correspondence with his friends Ernst Laslowski, Fritz Blum, and Theophil Reese 200
I.7 Correspondence with friends in Meßkirch, Todtnauberg, and Freiburg 150
I.8 Private correspondence 1,500
II.1 Correspondence with Kurt Bauch 144
II.2 Correspondence with Karl Löwith 115
II.3 Correspondence with Walter Bröcker, Friedrich Gundolf, Werner Jaeger, Gerhard Krüger, Walter F. Otto, Wolfgang Schadewaldt, Bruno Snell, and Julius Stenze 200
II.4 Correspondence with Julius Ebbinghaus, Hildegard Feick, Georg Misch, Hermann Mörchen, Hermann Nohl, and Manfred Schröter 200
II.5 Correspondence with Beda Allemann, Wolfgang Binder, Ivo Braak, Max Kommerell, Paul Kremer, Paul Kuckhohn, Eduard Lachmann, Emil Staiger, Ingeborg Strohschneider-Kohrs, Leopold Ziegler, and Franz Zinkernagel 250
II.6 Correspondence with Max Müller, Gustav Siewerth, and Bernhard Welte 200
II.7 Correspondence with Elisabeth Blochmann 112
II.8 Correspondence with Jean Beaufret 250
II.9 Correspondence with Romano Guardini, Engelbert Krebs, and Karl Rahner 250
II.10 Correspondence with Medard Boss, Ludwig von Binswanger, and Victor von Gebsattel 350
II.11 Correspondence with Erich Rothacker, Eugen Fink, Paul Häberlin, Maria Scheler, Ludwig Langrebe, Paul Natorp, and Oskar Becker 200
II.12 Correspondence with Hans Kock, Bernhard Heiliger, George Braque, Hans Wimmer, Otto Dix, and Carl Orff 100
II.13 Correspondence with Jean-Paul Sartre, Otto Pöggeler, Hans Jonas, Hartmut Buchner, Helene Weiß, and Walter Biemel 250
II.14 Correspondence with Ernst Jünger, Friedrich Georg Jünger, Egon Vietta, Paul Celan, and Andrea von Harbou 120
II.15 Correspondence with Käte Victorius, Walter Schulz, Wilhelm Szilasi, and Gottfried Martin 100
II.16 Correspondence with Edmund Husserl, Heinrich Rickert, and Jonas Cohn 150
II.17 Correspondence with philosophers and persons from Asia, South America, the USA, and Canada 250
II.18 Correspondence with philosophers and persons from Asia, South America, Canada and the USA 300
II.19 Correspondence with Heinrich Wiegand Petzet, Hans Jantzen, Marilene Putscher, and Inge Krummer-Schroth 250
II.20 Correspondence with Ludwig von Ficker and Imma von Bodmershof 120
II.21 Correspondence with Rudolf Bultmann 120
II.22 Correspondence with Clemens and Dorothea Podewils 350
II.23 Correspondence with Karl Jaspers 155
II.24 Correspondence with Hannah Arendt 169
II.25 Single letters I 300
II.26 Single letters II 300
II.27 Zusatzband 500
III.1 Correspondence with Gütnher Neske Verlag and others 300
III.2 Correspondence with Vittorio Klostermann Verlag 500
III.3 Correspondence with Academies in Berlin, Munich, and Heidelberg 400
III.4 Correspondence with universities 600
III.5 Correspondence with other institutions 250
III.6 Correspondence with the cities of Meßkirch, Todtnuberg, Marburg, and Freiburg 150

Notes and References

1 Martin Heidegger, Platons Lehre von der Wahrheit/Brief über den Humanismus (Bern: Verlag Francke, 1947).

2 translation of “Brief über den Humanismus.” This volume contains both the Fench original and a Dutch translation (Martin Heidegger, Over het humanisme, transl. by Chris Bremmers (Budel: Uitgeverij Damon, 2005), 9–15)

3 William J. Richardson, SJ, Heidegger. Through Phenomenology to Thought (The Hague: Martinus Nijhoff, 1963).

4 Martin Heidegger/Kurt Bauch, Briefwechsel 1932–1975, herausgegeben und kommentiert von Almuth Heidegger (Freiburg/München: Karl Alber, 2010), 14.