What follows is Michael Heim’s original Translator’s Introduction to The Metaphysical Foundations of Logic by Martin Heidegger. The English translation of Heidegger’s The Metaphysical Foundations of Logic first appeared in 1984 and is still available from Indiana University Press. The Translator’s Introduction, however, appeared as a separate insert in only a limited number of the cloth-bound first editions in 1984-85. The reason for the peculiar publishing procedure was complex. Briefly stated, Heidegger’s family became involved in the publishing of his works after his death. The translation of several books by Heidegger was supported by grants from the National Endowment for the Humanities. The NEH-sponsored scholarly translations contract the translator and publisher to provide an introduction, as well as a glossary, for English-speaking readers. In the case of this translation, however, the Heidegger family intervened in the early 1980s to protect what they believed to be the deceased Martin Heidegger’s wishes concerning the translation of his Collected Works (Gesamtausgabe). The family fought vehemently to exclude from the English-language volume everything but the text as published in the German-language edition, and the family specifically forbade the NEH-sponsored introduction for English-speaking readers. Caught in a legal bind, the publisher sought to satisfy both the NEH mandate and the Heidegger family by having the Translator’s Introduction bound separately as an insert to accompany the printed volume. After the first printing, however, the Translator’s Introduction ceased appearing with the volume. Because I receive occasional requests to see this introduction, and because it is not available elsewhere, I place it here for those studious few who pursue these matters. -M.H. (May, 1996)

Much recent philosophy is a debate over whether or not the necessities of logic are indicative of necessary traits of reality. Does the modern logical system have implications for describing what is ultimately real? Or can languages be developed, both natural and artificial, which have no more ontological commitment than is required for internal self-consistency? Positions in debate range from Quine’s minimalist nominalism to Russell’s mathematical Platonism (a commitment to the existence, or “subsistence,” of abstract entities such as universals or real sets); sometimes a Kantian approach is urged, to establish the conditions necessary for any reference to extralinguistic reality, as in Kaminsky and Strawson.

The debate arises along with a deep underlying uncertainty, the uncertainty accompanying the success of the logical calculus in the twentieth century. With the rapid growth of modern logic, a full system of proof is offered in which great scope and consistency are attained with unprecedented rigor. A powerful symbolic system of crystalline clarity seems to have absorbed the previously dominant logic based on the syllogistics of Aristotle. Yet mathematical language, the calculus of propositions, is a system of symbols equally applicable to electronic switching-circuitry as to assertions made in natural language. The symbolic logic of propositional and predicational relations seems to prescind from any intrinsic connection with direct assertions or general truths (premises based on species-identities, as in Aristotle’s eidei). The formalism achieved by relational logic seems to render irrelevant any specific embeddedness in any particular domain of reasoning. Just as geometrical axioms are no longer bound to the domain of circles (physical figures) but are operable with contrary postulates, so too logic is now gradually freed of any naturally given syntax.

The result is philosophical uncertainty. Is traditional syllogistics still a feasible model for rational discourse and for the explanatory elaboration of proof, or is it merely an interesting variant of a system based on widely accepted but contingent postulates. Further, is logic — in an essential way — largely irrelevant to everyday nonscientific argumentation?

This philosophical uncertainly can be seen in the pedagogical chaos of logic textbooks. While generally reluctant to revive Aristotelian syllogistics, textbooks become increasingly experimental in an effort to bring forth a model for rationality. There are texts which put forward unadulterated mathematical logic, a branch of pure mathematics, and ignore the intelligent student who winces at the excruciating violence done to language in the name of “translation” and ”well-formed formulas.” Other texts subscribe to an amorphously “informal” logic aimed at detecting fallacies, providing merely a negative model for rationality. And then there are numerous attempts at rhetorical approaches to material logic, efforts that demonstrate great ingenuity but begin from arbitrary starting points, and in which complex rules for diagramming arguments are proliferated, but with no foundation in systematic intellectual principles.

It is not therefore surprising when a philosopher comes boldly forth and declares provocatively that we have “two logics” (Henry Veatch’s book by that title in l969): first, a traditional (Aristotelian) logic with rules for the predicative inferences ”natural” to the spoken and written word; and second, a “spider-like” calculus which weaves logical relations of great technical power and abstraction without, however, being grounded in any particular human purposes or without being interpretive of a definite experiential domain. To point out such a state of affairs or quid facti is troubling, not only on account of the pedagogical perplexity, but we are left philosophically uneasy with the existence of “two logics” until we can answer the question quid iuris: By what right do we advance one over the other as a standard or model for reasoning? Is it possible philosophically to ground the primacy of one over the other?

The question is exacerbated by recent developments in combinatorial logic systems. Artificial languages are springing from formal systems and are increasingly widespread in computational and cybernetic applications. The formalized logic of these systems is rapidly becoming a “second language” throughout the culture. Is rationality thus unitary, homogeneous insofar as we abstract from natural language with its heavy baggage of historical accretions and organic growth? Or are we permanently involved with two or more logics, it being necessary to work out each formal system from the perspective of the language we inherit as members of a historical culture? Is mathematical logic a cultural opportunity to shed the blind accumulations of history? Or is it the intellect’s most dangerous game to weave a free-floating rationality that is no longer rooted in the communication that occurs among certain mammals in cultural situations?

Put simply, the crisis arising from the current plurality of logics is how to ground a logic as a model of rationality or whether or not to ground logic at all. A logic may be grounded by demonstrating its rootedness in reality, through a theoretical metaphysics that shows the necessity of logical truth. Besides establishing metaphysical rootedness, another way of grounding logic is to argue for the ontological commitments of a given logical system by showing what reality structures the logic refers to by implication. These two ways of grounding, rootedness and implication, differ in their respective directions: metaphysical rootedness grounds by proceeding from an account of reality to the rationality of a logic; the way of implication begins with a rational system and proceeds to the structures of reality implied by that system. For instance, the traditional predilection for Aristotle’s syllogistics rests on the rootedness of that logic in an orderly structure of being: reasoning through inferences based on increasing generality and ontological intelligibility (i.e., permanence and hierarchical integrity of being) provides a scheme in which arguments can be adjudicated by referring finally to higher and qualitatively more valuable “first principles,” even to the ultimate appeal to a Prime Mover or originary principle (first premise). Aristotelian logic is an example of logic grounded through its rootedness in ontology.

The Metaphysical Foundations of Logic (hereafter MFL) by Martin Heidegger is a study of the ontological commitments of a system of logic as that logic is rooted in a theory of reality or metaphysics. But in Heidegger’s work, neither ”ontology” nor “commitment” pass for self-evident or unanalyzable assumptions. In fact, the chief endeavor of the volume of lectures is to patiently develop a rich notion of commitment as it pertains to the grounds of inferential reasoning, as well as a rich notion of ontological grounding as it involves an inherent commitment. And the book as a whole is yet another facet of Heidegger’s sustained attempt to question the ramified significance and current potential of the traditional term ”ontology.” One will be therefore disappointed if one seeks here a grounding of logic upon naked appeal to “what there is,” or to “actual existence,” or to ”mathematical Platonism” as mythical belief in the “reality of abstract entities.” Heidegger’s discussion does indeed touch on Platonic ontology, but does so by raising questions regarding the implicit temporalization of “being” in Plato’s sense of the term. In other words, mathematical Platonism is here treated less as a commonplace “ism” than as an opportunity to re-think Plato’s point of departure.

The original German title of MFL, Die Metaphysische Anfangsgründe der Logik im Ausgang von Leibniz, makes explicit reference to Gottfried Wilhelm Leibniz (1646-1716). The entire half of MFL is a meticulous exegesis of Leibniz’s notion of propositional truth. In it Heidegger claims to have proven the rootedness of Leibnizian logical theory in the monadological metaphysics of Leibniz. TheAnfansgründe of the title is untranslatable, as is also im Ausgang von. Anfangsgründe covers meanings such as ”elemental bases,” “initial premises,” and principial grounds.” Im Ausgang von can mean “beginning with,” as well as “proceeding from.” So the original title refers to the foundations or grounds of logic as it is found in and as it develops out of Leibniz. The specific nature of that foundation, whether of rootedness or of implication, is the matter elaborated in the volume, though these terms are not Heidegger’s.

Leibniz pioneered, among other things, the logical calculus. Both Bertrand Russell and Alfred North Whitehead, co-authors of the epochal Principia Mathematica (19l0-13), were indebted to him. Whitehead’s metaphysics is a striking parallel to the monadology, and Russell’s first major book is A Critical Exposition of the Philosophy of Leibniz (1900). It was Leibniz’s peculiar approach to inferential reasoning which made him the shaper of modern logic. As early as the De arte combinatoria (1666), he believed inferentia1 reasoning to be assimilable to a universal calculus of human knowledge. Such an exhaustive calculus would require a “universal grammar,” a characteristica universalis , which would serve to formalize in a deductive rigorous way all reasoning and scientific proof. The science of symbols proposed by Leibniz was to establish and foster the organized unification of scientific research within a single system of combination and permutation. To this end also, Leibniz worked on different models of the calculating machine throughout his lifetime. Appropriately enough, it was Leibniz’s binary number system which was to be used centuries later by John von Neumann in developing electronic computers at Princeton.

But Leibniz was more than a logician. His contributions go beyond mathematics to include physical science, theology, politics, and history. As a courtier, diplomat, and ecumenical theologian, Leibniz worked constantly toward the harmonious unification of the European world — he was even a pioneer Sinologist. His active advocacy of a universal symbolics seems to have had much to do with furthering international cooperative work in sciences as it did with the ”pure” invention of a formally rigorous language system. In an age of religious wars and with the inception of national states, Leibniz devoted his energies to the formation of a harmonious world-federation based on the context-neutral language of scientific understanding. For Leibniz, scientific understanding contravened neither theology nor ancient philosophy; all could be conciliated within a single ordered system. As a proponent of organized research, Leibniz developed a modern theory of rationality to unify the civilized world, and his monadological metaphysics may be viewed as a projection of the first principles of a diverse but homogeneous world-order.

In his book on Leibniz, Bertrand Russell completely dissociates Leibniz the logician from Leibniz the metaphysician, suggesting that the metaphysical and theological writings represent not the real views of Leibniz but merely the public mask shaped under social and political pressures. Countering this once-dominant assessment, Heidegger’s lectures on Leibniz in MFL show step-by step the rootedness of Leibnizian logic in the ontology of the monad. Proof for the interdependence of logic and ontology is a detailed demonstration of the intrinsic correlation between truth structure of the proposition and the metaphysical structure of the monad. Issuing from this demonstration is Heidegger’s claim that the philosophical consideration of logic is properly a “metaphysics of truth.” In other words, philosophical logic is of a piece with the philosophical questions of metaphysics. And to sever Leibniz the logician from Leibniz the metaphysician is to prevent a properly philosophical understanding of the model of modern rationality initiated by Leibniz.

Yet it would be misleading to introduce MFL as a mainly destructive attack on the prevailing picture of a dichotomized Leibniz. Like Heidegger’s Kantbuch, his Leibnizbuch is a critical destruction in another sense. MFL constitutes another part of the larger project begun in Being and Time , another facet of the endeavor to raise again the question of being through a critical re-examination of the philosophical tradition. Just as the Kantbuch challenges the isolation of an epistemology presumably free of ontological assumptions, so, similarly, the Leibnizbuch questions the isolation of a formal logic independent of ontological truth. Heidegger shows, through the specific analysis of Leibniz and through other more general arguments, that logic is grounded in a definite conception of being.

It is not that Heidegger calls attention to the ontological foundations of logic in order to insert under logic some preconceived ontology of his own. While the critical destruction of logical formalism does indeed belong to the “fundamental ontology” developed in Being and Time, the work of fundamental or foundational ontology is itself directed not at producing yet another and different ontology but it aims at reawakening a sense for the meaning of “being” as a question. The ”fundamental” ontology of Dasein is therefore part of Heidegger’s exploration of foundational problems, and that is why the discussion of Being and Time and the clarification of his descriptive ontology of Dasein play such an important role in MFL. Strong evidence for the foundational nature of the ontology Heidegger develops — as opposed to an ontology to rival that of Leibniz — is the frequency with which the formulations of the foundational ontology reflect the influence of the Leibnizian conception they are to illuminate. This reciprocity is at times uncanny, especially in the original German, and Heidegger explicitly refers to this hermeneutical circularity near the end of the book.

What the second half of MFL explores is the very nature of foundations or grounds. The reader who was once perplexed by the gnomic succinctness ofVom Wesen des Grundes (translated by Terrence Malik as The Essence of Reasons) or by the poetic reaches of Der Satz vom Grund will find here much light, because the lectures spell out every, or nearly every, step of an intricate argument. The progressive discovery of the metaphysical foundations of Leibnizian logic leads to the meta-foundational questions about the meaning of “grounding,” of ”commitment,” of the substantive ”being” referred to by metaphysics. Here Heidegger analyzes ”ontological commitment” as something considerably more weighty and fateful than the mere implications of a “discourse” or ”theory.” He takes apart the ontological root of Leibnizian logic to exhibit temporal ecstases of Dasein’s understanding-of-being, and he explicates commitment as the freely self-obligating structure of finite existence. To state it preemptively as a conclusion or ”result,” ontology or an understanding-of-being is the intrinsic free movement of Dasein to commit itself to a “world” or complex of involvements.

The metaphysics, then, which Heidegger finds at the foundation of modern logic is not simply an ontology of things, of substances and their relations, of individuals and their predicable properties. It is rather a pre-theoretical and implicit projection of a “world” by finite freedom. Such is the meaning of metaphysical statements; they are expressive of world or of a context of involvements. The world, in this sense, is an existential matrix for the generation of things, of individuals and their predicates. So it is the process of grounding that is to be observed in the world-disclosing significance of metaphysical statements and not simply some absolute referent of a metaphysical principle. Rather than a fixed set of conceptions, the metaphysics uncovered reveals the historical world or implicit contexture of meaning of the logic in question, what historians call the Sitz im Leben or ”life-setting” of the logic. There is some resemblance here to John Dewey’s efforts to deconstruct the theoretical independence of formal logic by finding logic to be an immanent procedure for solving “problematic situations.” In the pragmatic understanding, logical formalism is a reconstructed version of the historically concrete logic-in-use. But the resemblance ends at the point where Dewey proposes the scientific model of inquiry as continuous with “how we think,” whereas Heidegger regards thinking as an epochally transformative process based on a finite cultural project or ontological understanding of reality.

What then is the existential meaning or historical world covered in Leibnizian metaphysics as the root of modern formal logic? MFL is a complex work of symphonic intelligence and any brief answer must necessarily impoverish Heidegger’s polyphony of themes. But part of the answer has to do with the projection of a model for a universal modern rationality. The ontological commitment that grounds the Leibnizian calculus of propositions project a certain world-meaning or way of involving oneself with things.

The foundational terms Heidegger employs for the analysis of metaphysical structures include “being-in-the-world” and the “temporal ecstases” of being. Being-in-the-world is itself a primal temporalization or movement of transcendental time. Within the trajectory of time — which is “transcendence” or the original “place” within which the relation between subject and object appears — all things are shaped, including the substantivization of things, the consciousness of subjectivity, and the coherence of systems. The self-grounding, self-initiating trajection of temporality is the paradigmatic ground for all other forms of ground: causes, reasons, proofs, and essences. Thus each “world” has its own peculiar temporalization of things, where everything is gathered within the circumscription of a characteristic “mood” or type of Befindlichkeit (”disposition” or state-of-mind, the way we for the most part find ourselves).

The temporalizing mood peculiar to Leibniz’s analytical formalism, i.e., to mathematical logic, is the all-at-once simultaneous totalizing presentness. Heidegger shows how the Leibnizian analycity of formal truth is grounded in an existential project to shape rationality along the lines of a distinct metaphysical model. The model is that of the visio Dei, the deity’s intuitive cognition which was put into the philosophical tradition by the Aristotelianizing Scholastics. It is the knowledge of God, at least in its temporalizing simultaneity, that serves as model for human cognition in the modern world as projected in the metaphysics of Leibniz.

It is not unusual to connect the origin of logical operators and syntactical structures with the awareness of moods. For instance, H.H. Price in his Thinking and Experience (Cambridge, 1953, p. 124) asserts: “Disappointed expectation is what brings NOT into our lives,” and Price goes on to connect the syntax of existential quantification and material implication to other experiential conditions. In his ”What Is Metaphysics” of 1929, Heidegger considers logical negation to be more derivative than basic kinds of negative experiences, such as harsh opposition, refusal, painful failure, and prohibitive strictures; these experiences open us, through anxiety, to a primal dimension of the world which can then be the basis for the understanding of logical negation in a formal sense. The philosophical priority of “annihilative experiences” would be obliterated or at least concealed if it were necessary first to subject them to a clean and rigid notion of formal negation, as Carnap tries to do in his harsh opposition to Heidegger’s study of nihilation.

But in MFL, the moodful dimensions of the world are additionally temporalized in the ecstases of primal time. and the temporalized world-project is the root from which formalized systems grow. Thus Heidegger finds the ontological commitment of modern formalism not in some presumptive referents of a system. Ontological meaning is not to be found merely in the suppositions a developed formal system makes about what there is. Rather, formalism displays a contraction of the temporalization process that gathers things into a certain kind of presence. The Leibnizian ideal of complete analycity in a systematic totality of true propositions is, culturally or seinsgeschichtlich, the continuation of the absolute presence of the medieval divinity. Later on in his work, Heidegger describes the modern period as an epochal displacement of the medieval search for the salvation of the soul by the quest for mathematical certitude in a homogenized world-culture. There are startling breaks in the epochal history of being, but there is also an unforeseen and unlikely continuity in retrospect.

These introductory remarks began by referring to two questions: Do the necessities of a logical system reflect, or correspond to, necessities in reality? Do we need a single logic to provide an accurate model of rationality? In conclusion, answers to these questions can only be adumbrated in the briefest possible way.

In MFL we find that Heidegger argues: (1) propositional logic is founded on a metaphysics of truth which is in turn founded on a general metaphysics — though the general metaphysics may not be immediately accessible and may require an excavation of latent principles; (2) the meaning of metaphysical statements needs clarification through an existential analysis which describes the experiential being-in-the-world derived from a finite world-project. To say that logic is rooted in metaphysics eliminates the problem of how to get logic to “picture” or “correspond to” reality; as an outgrowth of metaphysics, logic is a branch organically expressing the whole of an understanding-of-being. Other branches of that understanding include painting, architecture, and politics — all various world-disclosures of being. The necessities envisioned in a system of logic are founded in the self-obligating freedom that projects a world to which one is committed. And “commitment” means the determinate way in which transcendental time is contracted into a definite presence of beings. Furthermore, understanding-of-being is not an arbitrarily manageable human capacity, but is the existential structure (Dasein ) of the transcendence that characterizes human beings in their freedom and unfreedom.

Through his existential analysis of “world,” Heidegger undercuts the question concerning the universal model of rationality. Grounding is not only inferential; it is also existential. Since world, in the existential sense, admits of a plurality, the analysis of the Leibnizian metaphysics supporting modern logic highlights the finitude of the project to homogenize a planetary culture through a unified symbolics. Such a world represents indeed a unified oneness, but it remains, existentially, one of many possible worlds. In terms of its metaphysical meaning, however, the projection of a unitary world may be a European destiny that has been overcome from within by Heidegger’s own inquiry into the existential meaning of metaphysical truth. The European search for an absolute foundation, the fundamentum absolutum et incussum of Descartes, may be regarded as a great “Event” in which we still move, but from which we are now moving away. We are increasingly aware of the delightful and abysmal freedom to create a plurality of logical systems, and there is a growing critical awareness that all claims to completeness are deluded, even though such claims necessarily haunt every act of systematizing.

What then of the new ”philosophical logic” Heidegger calls for? How would such a postmodern logic take shape in the developing and teaching a postmodern model of rationality?

If we take our bearings from the later work of Heidegger can surmise that such a logic-in-the-making would emphasis the place or topos where two or more different worlds meet, where an exchange takes place over the gap of mutually divergent domains of meaning and involvement. Such a logic or logos would be self-opening and inherently translucent to that which lies beyond its own incompleteness. The later works suggest the model for postmodern logic by portraying the paradigm of conversation: philosophy converses with poetry; the philosophy of technology converses with Parmenides; the German philosopher has a dialogue with the Japanese philosopher. Fittingly enough, the give and take of conversation was the original locus within which the logic of argumentation was first studied and formulated by Aristotle. But more than argumentation is required in postmodem logic. In “A Conversation about Language between a Japanese and an Inquirer,” Heidegger has written in and emphasized the silences and intermittent hesitancies before what is unsayable between East and West, between two (or more) worlds. It may be necessary for logic, as a model of rationality, to protect the interstices of the unsayable, to affirm the fragile finitude of cultural symbolics. For without the patient protection of the plurality of worlds and of what is unsayable between them, there may be less likelihood of nurturing a diversified planetary culture as a response to the unspeakable.