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Introducing Heidegger’s Unpublished Seminars on Aristotle from the 1920s

Their Indispensable Contribution to a Critical Assessment Not Only of Heidegger’s Auseinandersetzung with Aristotle but of His Own Ontological Project as Shaped by This Auseinandersetzung

WHETHER OR NOT ONE IS IN SYMPATHY WITH the controversial contemporary philosopher Martin Heidegger, two facts are indisputable: his influence on subsequent thought, both in and outside of philosophy, has been enormous; few if any other philosophers have pursued such an intense and long dialogue with thinkers of the past and especially with those Greek thinkers who gave philosophy both its origin and its name. The latter aspect of Heidegger’s thought has become fully evident only with the gradual and continuing publication of his lecture courses and seminars. Even this extensive material, however, does not provide anything close to the full picture. To explain what is missing, a short background story is required.

After publishing a book on Heidegger’s reading of Plato (Gonzalez 2009), I set out to explore the full scope of Heidegger’s dialogue with Aristotle, a dialogue that shaped his own thought like no other. Aware at the time of a few unpublished seminars on Aristotle Heidegger had given during the 1920s, I set about exploring the student transcripts. In the process, I learned two things that form the basis for the present book. First, the unpublished material was much more extensive than I had anticipated. The very detailed student notes preserved at Stanford University among the papers of Heidegger’s student Helene Weiss (notes clearly taken not only by Weiss but by several students)¹ revealed that the seminars already known to me were more substantial than I had imagined, adding much to what could be gathered from the published courses. They also revealed the existence of several extremely important seminars previously unknown to me (and to all other scholars). Secondly, when 2012 finally saw the publication in Heidegger’s collected works (the Gesamtausgabe) of a large volume dedicated to his seminars on Plato, Aristotle, and Augustine (GA83), the volume turned out to contain only one of the seven seminars on Aristotle from the 1920s I had come across in my research (and with what I know to be the crucial final session of that seminar missing!). This is all the more surprising in that there is no plan for another volume of seminars on Aristotle.

While student transcripts must be treated with some hermeneutical suspicion, especially when there is no text by Heidegger against which to check them, I am convinced that the very detailed, extensive notes of Helene Weiss cannot be ignored. They give evidence of aspects of Heidegger’s reading of Greek philosophy that, while presupposed by what is found in the published texts, are not themselves to be found there as such.² For two of the unpublished seminars, notes by another student, Oskar,³ have been published that while inferior in length, detail, and comprehensiveness, fully corroborate Weiss’s notes where they overlap.

The goal of my book is to present this important material, completely unknown to the studies on Heidegger and Aristotle published so far,⁴ in as accurate and fruitful a way as possible so that it can serve as a crucial source for this extraordinary dialogue between the philosopher who arguably most shaped our philosophical tradition and the philosopher who sought to “destroy” it. The following chapters will provide a narrative reconstruction of each seminar that remains faithful to and fully acknowledges the transcripts used. The model here is to an extent what Theodore Kisiel⁵ did for other seminars and courses unpublished at the time (Kisiel 1993). The difference is that I will fully acknowledge my sources⁶ (so that accuracy can always be checked by other scholars) and will seek to provide in each case, not a general summary, but a detailed, class-by-class exposition of the argument and progression of the seminar (the Weiss transcripts are in most cases detailed enough to date each class). Where readings are uncertain or the notes seem confused so that there is reasonable doubt about what exactly was said, this will of course be indicated.⁷

The exposition of each seminar will include an introduction and explanatory notes that situate the seminar within Heidegger’s reading of Aristotle as a whole, indicate its unique contributions, and draw parallels between what is said within it and what we find in other (especially published) texts from the period. This situating is important because we are dealing entirely with student notes, and probably the best way of ensuring that these notes accurately reflect Heidegger’s thinking at the time is to show that, even when they make a novel point, they complement and are consistent with what Heidegger says elsewhere. Furthermore, these seminars are very focused on the Aristotelian texts; this is indeed part of their value because they often provide the textual basis for what Heidegger asserts elsewhere. The difficulty, however, is that in focusing on an isolated line here or there the seminars often presuppose the broader context of the Aristotelian work. For the reader to be able to follow the argument of the seminar, some of this context needs to be supplied, either in notes or in brackets. In short, each chapter aims to provide much more than a translation or mere summary of the transcript, supplying an informed and careful reconstruction, on the basis of the students’ notes, of what transpired in the seminar both interpretatively and philosophically. One can think of the transcript as preserving the skeleton of each seminar and the present book as seeking to restore the living thought that made these seminars as exciting and provocative as students claimed them to be.

But what exactly are the seminars in question? And in what lies their importance? Do they really offer something not found in the extensive published courses and seminars? And what actually remains of them to serve as the basis for our reconstruction? The full answers to these questions are found in the present book, but to provide some initial answers I outline the seminars here, indicating in each case the topics and texts discussed, the significance of the seminar in the context both of Heidegger’s interpretation of Aristotle and of his own philosophical development, and the material basis on which the seminar will be reconstructed (in other words, the character and extent of the surviving student notes). As already noted, in most cases the detailed Weiss transcripts allow us to date the seminars precisely. All of the Weiss transcripts mentioned here are manuscripts handwritten in different hands. Therefore, the substantial preliminary work was that of deciphering all of these manuscripts and converting them into clear and accurate typed texts. This has been done successfully, with only very few words or phrases proving illegible or of uncertain legibility. The seminars, then, are as follows:⁸

De Anima Seminar, SS 1921, May 14 to July 26

Topic: The goal is interpreting the being of the soul, though much time is spent on the preliminary question of how this being is to be accessed. In this seminar, moreover, it is the being of all life as such that is Heidegger’s focus, as it is Aristotle’s, and not human life in particular.

Texts discussed: While the second half of the seminar is a reading of De Anima, the first half focuses on the Metaphysics (particularly Book VII). This decision to read De Anima through the account of ousia in the Metaphysics shows that what Heidegger seeks in the former text is an ontology of life. As the Weiss transcript makes clear, the seminar was also supposed to address the account of motion in the Physics, though it never got around to doing so. As Heidegger’s focus on the Physics in later seminars shows, he maintains that Aristotle’s interpretation of the being of life can be understood only through his interpretation of the being of motion.

Importance: It is not an exaggeration to say that this first seminar on Aristotle sets the agenda for all subsequent ones. In particular, we see already Heidegger interpreting the key concepts of dunamis, energeia, and entelecheia in the context of the phenomenon of life and, more specifically, in the context of what he calls the “I-can,” what will later become the characterization of human-being (Dasein) as possibility. Indeed, as I have shown, this 1921 seminar anticipates key methodological decisions and key theses of Being and Time (Gonzalez 2018a).

State of the transcript:⁹ Helene Weiss appears to rely partly on the notes of other students for some of this. The writing is very faint and bleeding through from verso. The notes are also very cryptic and fragmentary, far from clearly reproducing the narrative flow of the seminar. Yet as finally deciphered, they indicate clearly enough the overall movement and argument of the seminar.

Other sources: A transcript of this course by Oskar Becker was published in 2007 in volume three of the Heidegger-Jahrbuch.¹⁰ This transcript, however, while more detailed than the Weiss transcript when it comes to the first half of the seminar on the Metaphysics, is much less detailed when it comes to the second half on De Anima. Indeed, Becker misses an entire class on De Anima and is so laconic with the other ones that his transcript leaves one wondering why this was called a seminar on De Anima in the first place. The Weiss transcript, in contrast, leaves one in no doubt about the seminar’s focus on De Anima and is an indispensable supplement to the Becker transcript. Kisiel’s account of this seminar (1993) relies entirely on Becker, as only in this way could he have asserted, “The problem of defining the soul in the first two books of De Anima is raised briefly only at the start and finish of the semester” (230). The Weiss transcript shows that half of the classes were devoted entirely to De Anima.¹¹

Übungen über Phänomenologische Interpretationen zu Aristoteles (Nikomachische Ethik VI; de anima; Metaphysik VII), WS 1922–23, November 2 (?) to February 19

Topic: Aristotle’s ontology of life.

Texts discussed: Nicomachean Ethics VI.2; De Anima III.9; Metaphysics VII.1–3.

Importance: It is here and nowhere else that Heidegger, through a very detailed and unorthodox reading of specific texts, develops that interpretation of the phenomenon of life in Aristotle that will so definitively shape his own account of human being (and what he will call human facticity). This reading has its start in the SS1921 seminar, but it is fully developed only here.

State of the transcript:¹² We have from Helene Weiss seventy pages of detailed, handwritten notes that follow very closely and faithfully the argumentative progression of the seminar. The handwriting changes at points, which suggests the intervention of other hands.

Other sources: A transcript by Oskar Becker was published in 2007 in volume three of the Heidegger-Jahrbuch, but it is far inferior in both comprehensiveness and clarity to the Weiss transcript. We have in the Becker transcript isolated notes that do not reproduce, as does the Weiss transcript, the development of the argument. Becker’s transcript for both this seminar and its continuation in the summer (see the following) totals 56 pages, whereas the Weiss transcript for both seminars totals 108.

Continuation of Seminar from WS1922–23, SS 1923, May 4 to July 5

Topic: Aristotle’s ontology of life.

Text discussed: Nicomachean Ethics VI.

Importance: This is Heidegger’s first account of the so-called dianoetic virtues in Aristotle, to which he will return repeatedly in later courses. It is instructive to see them examined first in the context of an ontology of life (and not at all in an ethical, nor even exclusively human, context). Also, we already see the important role that the notion of phronêsis will come to play for Heidegger. Indeed, it is here that we first find Heidegger’s claim, made famous through Gadamer’s later recollection, that phronêsis is conscience (Gewissen).

State of transcript:¹³ We have from Helene Weiss thirty pages of detailed handwritten notes that follow very closely and faithfully the argumentative progression of the seminar.

Other sources: The transcript by Oskar Becker published in 2007 contains five pages (43–48) that stem from the summer semester. But apart from being so meager, the failure of the Becker transcript to provide dates results in the editors being completely unaware that the notes belong to the summer semester or that the seminar even continued into the summer. They write, “Whether Heidegger continued the seminar of winter 1922/23 into the summer semester cannot be clearly decided on the basis of the Becker transcript. Presumably he continued it only for a few hours” (Denker 2007, 49; my translation). The chronological list of Heidegger’s works in Denker 2004 does not list the course, though it refers in a footnote to Kisiel’s hypothesis of the course’s existence (475n37). Only the Weiss transcript shows that the seminar not only most certainly did continue into the summer, but that it did so for more than “a few hours.” The Becker transcript also has serious lacunae, which we can see by comparing it to the Weiss transcript: it is completely missing the classes of June 1 (in which Heidegger made his famous connection of phronêsis with Gewissen), June 28, and July 5, as well as most of June 21.

Seminar on Nicomachean Ethics I, SS 1923, first class undated, second class dated June 2, and last class dated July 2

Topic: Praxis as care (Besorgen) and the telos of the good as being-completed (Fertigsein).

Texts discussed: Nicomachean Ethics I.

Importance: We see here the emergence, in the context of an interpretation of good action in Aristotle, of the concept of care that will prove so central to the ontological explication of human being (Dasein) in Being and Time.

State of transcript:¹⁴ We have from Helene Weiss twenty-three pages of detailed notes.

Other sources: None to my knowledge.

Seminar on the Physics WS 1923–24 (sessions undated)

Topic: The Greek conception of being as what is already and always there in contrast to accidental being.

Texts: Focus on Physics II, but a wide range of other texts are considered.

Importance: We find Heidegger here starting to focus on the temporal dimension of the Greek conception of being and in this context again reflecting on the central terms of dunamis, energeia, and entelecheia. Especially significant is his reading of Physics II.4–6 on tuchê and to automaton, a text he describes as never afterwards being surpassed in the originality of its analysis of temporality (Zeitlichkeit). It is no wonder that Helene Weiss herself pursued this topic in her 1942 book.¹⁵

State of transcript:¹⁶ We have eighteen pages, front and back, on nine sheets of paper. The notes are undated and clearly marked as being only notes taken from the seminar rather than an attempt to replicate its progression. The seminar therefore cannot be reconstructed in any great detail from these notes, but, as already indicated, what can be learned from them are some very important developments in Heidegger’s reading of Aristotle.

Other sources: None to my knowledge.

Zur Ontologie des M A [Mittelalters]: Kleine Summa des Thomas, WS 1924–25, No date for first class, second class dated November 10, 1924, last class dated February 23, 1925

Topic: Greek ontology as an ontology of the world misapplied in the later metaphysical tradition to the being of the divine and human being.

Texts discussed: Metaphysics IX.

Importance: This seminar is of enormous significance. Though overlooked on account of its title, it is in large part a detailed reading of Aristotle and of Metaphysics IX on dunamis/energeia that, while of central importance to Heidegger’s interpretation of Greek ontology, is discussed in such detail only here. The transcript also shows the seminar to have been an extraordinarily sustained, detailed, and organized hermeneutical argument, as much so as any of the published lecture courses.

State of the transcript:¹⁷ We have from Weiss sixty-two dense pages in small handwriting. The handwriting is mostly clear and, more than any other, the transcript reads like a continuous exposition rather than as a series of notes. Weiss’s transcript is so complete because, as it clearly indicates, it reproduces the protocols of a number of students.

Other sources: These protocols can be found at the Deutsches Literatur Archiv in Marbach (catalogue number 75.7248). While Weiss quotes from them to supplement her own notes, the latter are independent and preserve much extra material.

Seminar on Physics III, SS 1928, May 14 to July 24

Topic: The ontology of motion. Heidegger develops here the notion of human being as the absolute motion from which alone motion and rest in the ontic sense can be understood. The notions of dunamis and energeia receive thorough and important treatment.

Texts discussed: Physics III, but also Metaphysics IX.6.

Importance: This seminar follows the publication of Being and Time and shows how Aristotle remains relevant to Heidegger’s project as he pushes even further his dynamic interpretation of being. Rather than the study of Aristotle’s Physics being simply something preliminary to the analyses of Being and Time, the latter are now used to better understand Aristotle’s Physics. Being and Time is far from being the last chapter of Heidegger’s Auseinandersetzung with Aristotle.

State of transcript:¹⁸ Weiss’s notes are unusually incomplete and hard to follow. The writing (by other hands?) is also in some cases nearly indecipherable, though I have deciphered approximately 99 percent of it.

Other sources: Fortunately, Heidegger’s own notes for the seminar (though very fragmentary and cryptic) and a set of protocols written by a number of students, presenting a much fuller picture of the seminar’s content, have been included in the volume of seminars published as Gesamtausgabe volume 83. However, there is a major lacuna. The Weiss transcript proves that the final session of the seminar was held on July 25 and reproduces in some detail what is an extremely important session dedicated to the account of energeia in Metaphysics IX.6. For some reason, this session is completely missing from the protocols published in GA83, and the editor, clearly not having consulted the Weiss transcript, wrongly affirms that the protocols “fully cover the course of the seminar” (667; my translation). Therefore, deficient as it otherwise is, the Weiss transcript proves indispensable.

Die ontologischen Grundsätze und das Katergorienproblem, WS 1928/29, November 9 to February 22 (with supplemental session on February 23)

Topic: Despite the title, the focus is not at all on the problem of the categories and almost entirely on one fundamental principle: non-contradiction.

Texts discussed: While the seminar commences with a discussion of Kant that anticipates Heidegger’s later major Kant interpretations, Kant’s insistence that the principle of noncontradiction is analytic and independent of any temporal determination leads to a detailed reading of Aristotle’s account and dialectical defense of the principle in the first few chapters of Metaphysics IV.

Importance: Such a detailed reading of Metaphysics IV and such an in-depth discussion of the principle of noncontradiction by Heidegger is to be found nowhere else. Furthermore, we find Heidegger here not critiquing the principle, as we might expect, but rather grounding it existentially in the being and temporality of Dasein. Here we have another example of how Being and Time does not end but rather renews interest in Aristotle.

State of transcript:¹⁹ For this seminar the Weiss transcript is 103 pages long and very detailed. It reproduces student protocols, with each class attributed to a different student.

Other sources: There apparently exist protocols for the seminar at the Deutsches Literatur Archiv in Marbach (catalogue number 75.7258), which I have not been able to consult, but they presumably are the same protocols reproduced by Weiss. The very existence of this seminar is not so much as mentioned in any of the literature, though Heidegger himself refers to it in one of his published courses (GA29/30, 533).

The above outline of the unpublished seminars not only indicates the important contribution of each to Heidegger’s Auseinandersetzung with Aristotle, but also displays a clear and cohesive trajectory: the ontology of life found in De Anima is developed, by way of interpretations of the Nicomachean Ethics and the Physics, into the analysis of Dasein pursued in Being and Time, while the latter provokes deeper analysis of the dynamic character of being in Aristotle’s Physics and consideration of Aristotle’s existential grounding of the fundamental ontological principles. The present book, therefore, will not be simply a compendium of narratives of individual seminars, but will also present a general narrative. It is indeed striking that while the published lecture courses add much to our understanding of Heidegger’s reading of Aristotle, these unpublished seminars, taken together, give us largely the whole picture, that is, the whole picture of one phase, though arguably the richest and most important, of Heidegger’s Auseinandersetzung with Aristotle. The next phase will be the reading of the 1930s with the course on the first three chapters of Metaphysics IX (GA33) and the essay on Book 2 of the Physics (WB). The final phase consists of the war and post-war seminars published recently in volume 83 of the Gesamtausgabe. The final chapter of this book will situate the unpublished seminars of the 1920s in relation to these later phases.

Here, however, it will be helpful to say something about the published lecture courses and how they relate to the unpublished seminars that will be our focus. The earliest published course devoted to Aristotle in name is the WS1921/22 Phänomenologische Interpretationen zu Aristoteles: Einführung in die phänomenologische Forschung (GA61), but that course in fact contains no reading of Aristotle’s texts. The first course that delivers what the title of the WS1921/22 course promises is the SS1922 lecture course Phänomenologische Interpretationen Ausgewählter Abhandlungen des Aristoteles zur Ontologie und Logik (GA62). This course comes between the SS1921 seminar on De Anima (as well as Metaphysics VII) and the WS1922/23 seminar with its SS1923 prolongation that continues the reading of De Anima and Metaphysics VII and transitions to an interpretation of Nicomachean Ethics VI. The SS1922 lecture course, however, considers none of these texts, its focus instead being the first two chapters of Metaphysics I and the initial chapters of Physics I. We do see this course carrying out, however, something anticipated by the 1921 seminar: the shift of focus from the Metaphysics to the Physics, with the justification that the latter provides the true foundation for ontological inquiry.²⁰ Thus in the SS1922 course, after a detailed reading of the first two chapters of the Metaphysics that only introduce us to “first philosophy” (by addressing the question of what “wisdom” is), Heidegger immediately turns to the Physics as if what is promised in the Metaphysics were found there (or at least could only find its foundation there). It is also worth noting that the SS1922 course contains an “excursus” on the account of energeia in Metaphysics IX.6: a crucial text that Heidegger will return to and interpret more extensively only in the unpublished seminars, especially the WS1923/24 seminar on medieval ontology.

The next published course on Aristotle is the SS1924 Grundbegriffe der aristotelischen Philosophie (GA18). The focus in the first part of this course is entirely on human being, such that the texts read are taken from the Nicomachean Ethics, the Rhetoric, and the Politics. Some of this part of the course draws on the unpublished SS1923 seminar on Nicomachean Ethics I, but the two discussions are far from completely overlapping. The second part of the course focuses on the account of kinêsis in Physics III. The unpublished WS1923/24 seminar on the Physics has a different focus (Book 2), but the later 1928 seminar on the Physics will develop much further the interpretation of kinêsis. That the SS1924 course anticipates the project of Being and Time is easy enough to see. It begins with an account of human being (the interpretation of Aristotle’s ethical, political, and rhetorical texts here is strictly ontological) as a step toward the interpretation of being in the second half through the account of motion in the Physics. But this project is already evident in the unpublished SS1921 seminar, except that there the starting point is an interpretation of the being of life as such, and thus De Anima, and the interpretation of, and access to, being as such is sought in the account of ousia in the Metaphysics. Indeed, what we see in the SS1924 course is the carrying out of the project outlined in the so-called Natorp Bericht of 1922,²¹ one from which De Anima virtually disappears and in which the Physics takes precedence over the Metaphysics in the order of ontological exposition.²²

The next major published course on Aristotle can be considered that of WS1924/25, which, though on Plato’s Sophist (GA19), includes in its first half an extensive interpretation of the dianoetic virtues in Nicomachean Ethics VI. That interpretation continues the interpretation of Aristotle in the SS1924 course. As noted above, Heidegger already provided a detailed interpretation of Nicomachean Ethics VI in the unpublished continuation of the WS1922/23 seminar in SS1923. While the WS1924/25 course certainly builds on this earlier reading and adds to it, there is also much in the earlier reading that drops out of the later reading, at least in part due to the difference in context. The WS1924/25 reading, unlike that of SS1923, serves as a propaedeutic to the understanding of a Platonic dialogue. The earlier seminar, I would argue, gives us a better idea of why the interpretation of Nicomachean Ethics VI is so important in the context of Heidegger’s ontological project, independent of any relation to Plato. In any case, one must certainly read the two accounts together to get a full picture of Heidegger’s interpretation and appropriation of the dianoetic virtues.

The only other published course from the 1920s that deals directly with Aristotle at any length is the SS1926 course Grundbegriffe der antiken Philosophie (GA22).²³ We find here a wide-ranging discussion of Aristotle as part of a course that also deals with the Presocratics and Plato. The treatment is therefore necessarily synoptic and superficial. However, a number of the more interesting claims made about Aristotle in this course receive their full explanation and justification in the unpublished seminars. One could see the SS1926 course as providing a snapshot of a five-year-long, intense engagement with Aristotle’s texts. When, for example, Heidegger asserts that the first phenomenological grasp of the phenomenon of life in Aristotle led to the interpretation of motion that in turn made possible the radicalization of ontology (GA22, 182), he is essentially giving a summary of the SS1921 seminar on De Anima without any of the textual support or argumentation found only there. Also, when he describes his own aim as being that of a “pan-dynamism of being in general” (170), he is formulating the outcome of his reading of dunamis (and energeia) in Aristotle, carried out most fully and thoroughly in the unpublished seminars.

It should be evident from the above that the unpublished seminars are very far from being inconsequential or made superfluous by the courses published in the Gesamtausgabe.²⁴ On the contrary, to use a worn-out metaphor, the published courses represent only the tip of the iceberg. One cannot come close to understanding fully the enormous formative role played by the detailed interpretation of Aristotelian texts in the development of Heidegger’s own thought without the unpublished seminars. One further cannot understand without them the extent to which the intense dialogue between these two thinkers continued beyond the publication of Being and Time: if the latter text was only a stop along the way of Heidegger’s own thought, so was it only a stop along the way of his intense engagement with Aristotle. The story of Heidegger’s reading of Aristotle, even in the 1920s, is not a story of the genesis of Being and Time, both because it continues beyond the publication of this text and because it opens up paths not taken in it (especially, that of an ontology of life inspired by De Anima). But without the unpublished seminars, we have little more than the projected book on Aristotle as a first draft of Being and Time.

It is in this context that I would defend the philosophical interest of reconstructing and critically engaging with the unpublished seminars. They raise fundamental questions about Heidegger’s trajectory of thought and his presuppositions—there is nothing like confrontation with an ancient text for revealing one’s own presuppositions—and about Aristotle’s thought. The last point is worth emphasizing. Even if, like the students of these seminars, we cannot always be certain whether it is Heidegger or Aristotle speaking, Heidegger does let Aristotle’s texts speak and in such a way as to make us question both them and ourselves. While the importance of the phenomenon of life in Aristotle’s thought cannot be doubted (consider not only De Anima but the biological writings comprising around a quarter of the extent corpus), did Aristotle succeed in accessing the phenomenon of life and grasping its being, or was his ontology guided by a paradigm of technical production that made success here impossible? And have we ourselves inherited ontological principles and categories that make the being of life inaccessible to us? And in that case what would be needed to let the phenomenon of life bring these principles and categories into question? While Aristotle did not identify motion with not-being, like Parmenides and possibly Plato before him, was he able in the end to escape their identification of being with constant, self-identical presence? Did his new concepts of energeia and entelecheia represent a radically new conception of being or just an attempt to reconcile the phenomenon of motion with the old conception? Do his Ethics, Politics, and Rhetoric tell us anything about what it means to be human, not just what it means to live well and live in a community, or do they assume that a human being is, ontologically, a being like any other but outfitted with special properties of cognition and action? Most generally, how are we to understand the relation between Aristotle’s ethics and his metaphysics, or between his biology and his metaphysics, or between his “psychology” and his metaphysics? Are they simply treated as distinct disciplines with no awareness of how they profoundly inform each other? How are we to think of these relations today? These are only some of the questions the seminars raise, and there can be no doubt that a result of being confronted with such questions (which receive little attention in the standard secondary literature on Aristotle) is a better understanding both of Aristotle and of the assumptions we today bring to the reading of Aristotle.

As for the questions the seminars raise regarding Heidegger’s own path, they are numerous and of great consequence. Why did Heidegger turn away from the phenomenon of life itself, which was his original concern and drew him to De Anima, to focus exclusively on human life? How and why did the ontology of life become an ontology of Dasein? What was lost in this shift of focus? And why was Heidegger never able to regain what was left behind here, not even, as will be argued in what follows, when he ostensibly returned to the question of life in the WS1929/30 course on the Basic Concepts of Metaphysics (GA29/30)? Why does Heidegger seek the meaning of being in Aristotle’s account of motion and thus in the Physics, rather than in the notion of energeia sharply distinguished from motion in the Metaphysics? Why does he seek the meaning of human being in dunamis rather than in what for Aristotle is the most central concept for understanding both life in general and human life in particular: again, energeia? Is the “pan-dynamism of being” really the only alternative to a conception of being as static presence? Is Aristotle’s conception of being as “activity” understood in such an alternative? And is the interpretation of Dasein as a being-possible whose only end is death the only alternative to a conception of Dasein in terms of presence-at-hand? Again, does not Aristotle’s “activity-possessing-its-end” (energeia/entelecheia) provide an alternative here? And does ethics really need to be bracketed in order to do ontology? Can and should an ontology of Dasein ignore the political and social content of the Politics and Rhetoric? Again, these are only some of the questions the unpublished seminars confront us with and again the result can only be a better, because more critical, understanding of Heidegger’s own thought.

This introduction already defines the structure of the book. The seminars will be reconstructed in chronological order, with one chapter devoted to each seminar, and the development of Heidegger’s reading of Aristotle from one seminar to the other will be traced. Constant references to Heidegger’s published courses during this period will situate the seminars in a broader context. Besides reconstructing a seminar as faithfully as possible, each chapter will also indicate the questions it raises with regard to both Aristotle and Heidegger. A final concluding chapter will address more directly and more extensively the interpretative and philosophical questions raised by the seminars as a whole, not to answer them, but to indicate the future study the seminars both demand and make possible.²⁵ The present work is not simply a work of excavating the past, but one of opening up future paths of investigation and thought. The hope is that “Aristotle and Heidegger” become less the title of an old story and more a forward-looking provocation.