Zhao Zhen: Engels' Original Contribution to Shaping the Materialist Foundations of Dialectics

Materialist dialectics is a crucial component of Marxist philosophy. As Lenin emphasized, dialectics is the "living soul" and the "fundamental theoretical basis" of Marxism; without it, Marxism would become "something one-sided, distorted, and lifeless." Marxist dialectics originates from Hegelian dialectical thought, having discarded the latter's idealistic "mystic form" and undergone a thorough materialist transformation. In the preface to the second edition of Anti-Dühring, published in 1885, Engels wrote: "Marx and I were, with the exception of one or two others, the only ones who rescued conscious dialectics from German idealist philosophy and applied it to the materialist conception of nature and history." Marx and Engels revealed and expounded upon materialist dialectics from different fields respectively: Marx utilized dialectics as the fundamental method for analyzing the laws governing the operation of the capitalist economy, presenting a dialectics of the socio-historical realm within his critique of political economy; Engels primarily formed the theory of the dialectics of nature by inducing the basic laws of motion in the natural world as revealed by natural scientific theories, and on this basis attempted to construct a general theory of dialectics.

I. Exploring a Rational Path to Strip Away the "Mystical Shell" of Hegelian Dialectics

Marx and Engels fully affirmed the significant status of Hegelian dialectics, maintaining that Hegel was "the first to present its general form of working in a comprehensive and conscious manner." However, "with him it is standing on its head. It must be turned right side up again, if you would discover the rational kernel within the mystical shell." It "must be 'sublated' ^[1] in its original sense—that is, its form must be critically destroyed, but the new content obtained through this form must be saved." How, then, should it be turned right side up? How can one obtain the rational kernel while discarding the mystical shell, and gain new content in the process of destroying the old form? Althusser argued: "Stripping the shell is by no means painless; it is actually a process of breaking the mystical form, which is to say, an act of transforming its kernel." Hegel’s systematic dialectical thought is predicated on idealism; for him, dialectics itself is presented as the movement and transformation of consciousness. Stripping away the idealistic shell is not a simple abandonment, but a reconstruction of the theoretical system.

1. Hegelian dialectics is confined to the domain of epistemology and possesses idealistic attributes

Hegel's dialectics is a product of the construction of theoretical thinking and possesses a rigorous logical interconnectedness. In particular, this logical interconnectedness fully assimilated the intellectual achievements of ontologism, epistemology, and conceptualism in human history, thereby reaching an unprecedented theoretical peak. However, because it is a product of mental construction, Hegel's dialectics manifests distinct idealistic attributes. Objectively speaking, these idealistic attributes are rooted in the internal logic of the development of dialectics itself. Since the ancient Greek period, people have attempted to generalize and summarize the phenomena and laws manifested in the movement of things, forming a naive form of dialectics. Because the understanding of the state of the world's motion at that time was superficial and fragmentary, the dialectics formed then exhibited simple, straightforward, and discontinuous characteristics, failing to form a complete theoretical system. Hegel's dialectics achieved the sublation and transcendence of the naive dialectics since ancient Greece. It is the second form in the history of the development of dialectics; it was formed in the 19th century—a time when human reason was highly exalted and natural science was progressing—and its characteristics of profound content, exquisite form, and complete system made it the highest theoretical achievement of grasping the world in a philosophical manner at that time.

The formation of Hegelian dialectics occurred against a profound theoretical background: the shift in the study of the fundamental questions of philosophy. Since the dawn of the modern era, philosophical research began to shift from "ontology" toward "epistemology." "What the world is" was no longer the primary question people pondered; it was replaced by "how to know the world." This shift was not merely a change in the problem domain, but signified the further awakening of human subjective consciousness. When the focus of research shifted from the world as a lone object to the question of the identity of man and the world, two independent existences appeared in the philosophical domain: the world and man. This shift actually separated man from the world and made him an object of philosophical study. Human consciousness—especially the reason embodied by consciousness—became the research theme of philosophy. The agency ^[2] possessed by man as the subject who knows the world became the most distinctive feature of the philosophy of this era. In Marx's view, The Phenomenology of Spirit is the true birthplace and secret of Hegelian philosophy. While this was certainly a criticism of the idealistic attributes of Hegel's philosophy, it also emphasized that it was precisely in revealing the evolutionary process of human consciousness and reason that Hegel presented dialectics.

As some scholars have pointed out: "In the speculation where transcendental philosophy after Kant was transformed into idealistic dialectics, the idea that everything immediate is mediated by subjective concepts became the dominant theme." Once human consciousness is isolated from objective reality, it exerts the creativity of reason to its extreme, breaking free from the constraints of the objective world to seek absolute freedom. Hegel believed: "The Idea can be understood as Reason (reason in the true philosophical sense), and also as Subject-Object; the unity of Ideality and Reality, of the Finite and the Infinite, of Soul and Body; it can be understood as the possibility that has actuality within itself; or that whose nature can only be conceived as existing, and so forth." Clearly, in Hegel, reason is substantiated ^[3] and possesses absolute freedom; it not only can know the world but contains the world within itself. Consequently, the problem changed: "how to know the world" became "how to construct the world." Hegel constructed a dialectically developing world with the Idea as the subject. While this ostensibly realized the full exaltation of human reason and subjectivity, in reality, it detached from reality and fell into the quagmire of idealism. Hegel's construction fully absorbed the achievements of logic—the science of the forms of thought—allowing the dialectical development of the Idea to be presented as a rigorous systemic structure, displaying the content of the Idea's evolution in a systematized form, thereby developing dialectics into a complete theoretical state.

Undeniably, Hegel’s philosophical system is complex and vast, encompassing nearly the entire world—including spirit, nature, and logic—and its content is all-inclusive. However, the starting point of this system is human consciousness; the Idea then becomes the primordial factor supporting various other factors within the philosophical system, and at the system's closed loop, everything is reduced back to the highest form of the Idea, namely the Absolute Idea. For Hegel, the core of philosophy is dialectics, which is an epistemology of how the subject perceives the world. He believed that by following the dialectical movement of the Idea as he expounded it, people could achieve true mastery of the world. Examined within the historical trend of the shift in philosophical thematic domains, what Hegelian dialectics embodies is not a philosophy of worldview but a philosophy of epistemology. In focusing on answering the question of "how to know the world," Hegel abandoned the inquiry into "what the world is." "What the world is" was not important because man could construct the world; this was essentially abandoning worldview for the sake of expressing epistemology, or rather, the worldview became a footnote to epistemology. In Hegel, "the system demand[ed] it, and so the method, to please the system, had to betray itself." "Because his philosophy was correct for his thinking, it was therefore the only correct one." Consequently, Hegel's dialectics is not dialectics in the sense of the world's origin ^[4], but a mystified, inverted dialectics.

2. Returning to the domain of philosophical worldview to seek the dialectics of the objective world

A philosophical worldview is fundamentally the distinction and opposition between the materialist and idealist positions. To overcome the idealistic attributes of dialectics, it must be established upon a materialist foundation. This is the simplest and most direct logic; however, conducting a thorough critique of Hegelian dialectics is not a simple replacement of "concepts." If it were that simple, a direct transformation of positions could not be achieved at all. Hegel treated the concepts formed by the movement of reason as actual existence, viewing the deduction of concepts as a replica of the movement of material objects. Consciousness and concepts, as manifestations of the subjective spirit, possess an inherent essence of agency; thus, propositions such as "substance is subject" and the "self-negation of things" could be established. It is precisely because of this that the dialectical movement of things could be reasonably explained and presented. Clearly, a critique of the idealistic attributes of Hegelian dialectics must thoroughly discard its theoretical system, especially the negation of its use of "reason" as a premise. To this end, Engels clearly pointed out that Hegelian dialectics "starts from pure thought, whereas here we must start from the most stubborn facts." What Engels sought to prove was that if dialectics exists, it is the "science of the general laws of motion of both the external world and of human thought," while the dialectics of concepts is "merely the conscious reflection of the dialectical motion of the real world." If dialectics does not exist in the real world, then the dialectics of concepts is nothing more than a subjective fabrication and must be thoroughly discarded. Of course, the objectivity of the existence of dialectics is beyond doubt; after all, people have recognized its existence since ancient times. Therefore, what Engels had to do was reveal the dialectics existing in the objective world. To achieve this, he had to re-examine the objective existence of dialectics in the real world through a comprehensive analysis of modern scientific theories. That is to say, Engels first had to break through the limitation of Hegelian dialectics being confined to epistemology and conduct an investigation and validation at the level of worldview.

In essence, dialectics is a kind of fundamental law, also known as the scientific theory of philosophy. Its formation needs to be established on the basis of various sciences, especially philosophical theories; it is a fundamental theory within philosophical theory that involves philosophical issues at various levels such as worldview, epistemology, and methodology. Because of this, different levels of dialectics are easily conflated and presented in a chaotic and mysterious form, as was the case with Hegelian dialectics. Hegel believed: "The dialectic is the moving principle of all movement, of all life, and of all activity in the real world. Equally, the dialectic is the soul of all truly scientific knowledge within the sphere of thought." Clearly, Hegel had recognized the universality of the existence of dialectics in the world, but he ultimately reduced the world to the movement of consciousness and reason; therefore, dialectics was merely the dialectics of consciousness and reason.

Engels pointed out in Ludwig Feuerbach and the End of Classical German Philosophy that the great basic question of all philosophy is "the relation of thinking and being"—that is, the question of which is primary, "spirit" or "nature," and whether they possess identity. These refer respectively to the question of philosophical worldview and the question of philosophical epistemology. Both the question of worldview and the question of epistemology contain dialectical connotations, because the two constituent elements of the fundamental question of philosophy—"thinking" and "being"—possess the attribute of the unity of opposites. The worldview focuses on the "opposition" between the two, while epistemology focuses on their "unity." By comparison, the dialectical factors in the identity of "thinking" and "being" at the epistemological level are more obvious, because thinking itself reflects agency, and its movement itself is a concrete manifestation of the dialectics of the world's movement. It was precisely at this level that Hegel formed the general form of dialectics, while the dialectics at the level of worldview had long failed to be revealed. Old materialism only saw the priority and decisive role of being over thinking, but ignored the other side of the problem—namely, the reality of thinking and its active counter-action—losing the necessary traction that "thinking" should have upon "being." Consequently, it became either a purely physical reductionism or a走向彼岸 (going to the other shore) ^[5] essentialism, eventually losing the fundamental position of materialism. Dialectical materialism certainly emphasizes the primordial significance of being, yet it does not overlook the "care" ^[6] of thinking; it maintains the relationship of the unity of opposites between "thinking" and "being" and sustains a necessary tension between the two.

Clearly, to turn the inverted system of dialectics right side up again, it is necessary to enter the first basic question of philosophy to re-expound dialectics and reveal its existence at the level of the objective world. This process of revelation is the subject's research and interpretation of the object, the generation of scientific theory under the mode of subject-object interaction, causing dialectics to be presented as a scientific theory that correctly reflects the laws of motion of the objective world. Hegel also admitted that cognitive thinking first resides in the first stage, namely the stage of the understanding ^[7],...

"It maintains fixed determinacy and the distinctness of each determination from one another," "starting from the understanding of given objects to obtain their specific differences"—this moment of the understanding ^[8] is the logical starting point of objective dialectics. "The starting point of dialectics is the objective investigation of the existence and process of things themselves, thereby revealing the finitude of one-sided determinations of the understanding." Engels began his dialectical exploration from the various natural sciences. On the basis of mastering the theories of multiple sciences such as physics, chemistry, and biology, he grasped the inherent determinacy of things. From this foundation, he sought to transcend the one-sidedness and limitations of the understanding, thereby entering the dialectical stage to discover dialectics. To complete this task, Engels followed the latest developments in the natural sciences for decades with consistent dedication. After moving to London and leaving commercial life, he spent eight years thoroughly "shedding his skin" ^[9] in mathematics and natural sciences, eventually writing Dialectics of Nature. In Engels' view, "the task was not to build dialectical laws into nature, but to discover them in it and to evolve them from it," and subsequently summarized it as the "science of the general laws of motion and development of nature, human society, and thought." The study of dialectics is not equivalent to natural scientific research; it must follow the basic paradigm of philosophical research and be integrated into the category of the unity of opposites between "thought" and "being." Only in this way can the dialectics of nature be prevented from becoming a reductionist philosophy. Engels' study of the dialectics of nature is merely a vital component of his study of dialectics as a whole; as a philosophical inquiry, the study of dialectics possesses a noble orientation toward social-ideal values. Precisely because of this, the dialectics of nature is neither a reductionist philosophy nor a philosophy of nature ^[10], but rather the natural form of dialectics.

II. Constructing the Theoretical System of Dialectics Based on the Real World

Through his research on the dialectics of nature, Engels conducted a thorough critique of Hegelian dialectics. However, one cannot conclude from this that Engels' dialectical thought is merely a dialectic of the natural world. Through his research, Engels established a scientific view of nature; this process simultaneously achieved the construction of a dialectical theory that thoroughly transcends Hegel's "self-development of the concept." It is a conscious reflection of the dialectical movement of the real world. Engels studied dialectics starting from the realm of nature—the domain with the most pronounced material characteristics—thereby laying a solid materialistic foundation for Marxist dialectics.

1. Dialectics Exists in a Material World Characterized by the Unity of Subject and Object

In Hegel's view, "Truly free thought is in itself concrete, and it is the Idea; and in all its universality, it is the Idea or the Absolute." Conversely, Engels believed that consciousness or thought is not something ready-made, but a product of the human brain, and man himself is a product of nature. This first established the materialist origin of the world. The material world possesses infinite richness, containing an infinite abundance of matter in various forms and under constant evolutionary development; "matter as such is a pure creation of thought and an abstraction... matter is nothing but the sum-total of all material things from which this concept is abstracted." Engels emphasized that the material world should not be regarded as existing in-and-for-itself ^[11] in isolation from humanity; rather, the material world and its origins must be understood through the interaction between man and nature. This is not to infuse spiritual elements into a materialist worldview, but to emphasize that account must be taken of the human factor objectively existing within the real world. This new worldview is precisely the dialectical-materialist worldview founded by Marx and Engels. The material world, characterized by the unity of subject and object, fully demonstrates that human thought and various capacities are "the result of a long, experience-based historical development." Engels criticized the natural sciences and old philosophies for dealing with problems only by severing the relationship between man and nature. On this basis, he clearly proposed: "The most essential and closest basis of human thought is precisely the modification of nature by man, and not solely nature as such; and human intelligence has developed in proportion as man has learned to change nature." Man himself is a product of nature, yet the birth of humanity endowed nature with unprecedented color and value; man as subject and nature as object together constitute the world of dialectical movement.

When Marx and Engels expressed the historical-materialist worldview in its entirety in The German Ideology, they emphasized that the sensuous world surrounding man "is the product of history, the result of the activity of a whole succession of generations." The interaction between subject and object endows the material world with active dynamic factors. Western Marxists have criticized Engels' dialectics of nature for lacking human and socio-historical factors, thereby questioning the essential attributes of his dialectics; this is actually a misreading of Engels' philosophical worldview. As early as the 1840s, Marx and Engels had established a new philosophical worldview, and the subsequent research on the dialectics of nature would certainly not violate this worldview. The dialectics of nature is essentially a dialectic of the unity of subject and object. The description of natural phenomena and the revelation of natural laws have never been detached from the practice of the subject. It is only that the realm of nature does not present itself with the subject as an internal object in the same way the social realm does. Nevertheless, the dialectics of nature is ultimately the laws of motion of the objective world as revealed by man as the subject. As for how to understand the dialectics of a world where humanity has not yet appeared or a world beyond the reach of human capacity—does dialectics not exist simply because there is no subject? The nature that man can recognize and speak of has already been integrated into the material world of subject-object unity. To pursue time outside of time or space outside of space is meaningless; Hegel called this type of infinity "bad infinity" ^[12]. Investigating such a contentless material world would yield nothing. Engels advocated for scientific suspension and active "white space" ^[13] regarding the unknown world: "it is solved day by day in the infinite progress of humanity." In essence, once an unknown world enters the scope of human cognition, it becomes an object of human knowledge; it is no longer an object in-itself, but presents dialectical attributes because it stands in opposition to the subject.

2. Dialectics Possesses the Essential Characteristics of Universal Connection and Motion-Development

Since dialectics is returned to the material world, it is necessary to master the basic state of the material world and, on this basis, grasp the essential characteristics of dialectics. For Hegel, the object of exposition was the consistent Idea itself; what needed to be revealed was the concrete manifestation of the Idea at different stages. The laws of connection, motion, and development were self-evident; once the cycle of the Idea's motion was described, the essential characteristics of dialectics would naturally follow. Engels possessed a profound insight into the essence of Hegelian dialectics. Engels pointed out that Hegel's philosophy of nature is one with his logic and dialectics; "his real philosophy of nature is to be found in the second part of the Logic, the Doctrine of Essence, which is the real core of the whole theory." It is only that within Hegel's idealist philosophical system, the philosophy of nature does not hold the status of a foundational theory; it is merely the application of the Idea to explain natural phenomena to serve the construction of the system. The philosophy of nature became a verification of the Idea's motion. Contrary to this "putting the cart before the horse" approach, Engels started from the latest natural scientific discoveries seeking the basic laws of motion in the material world, striving to explore the essential laws of dialectics objectively and empirically. When the focus shifts from the Idea to the material world, the objects of study become more diverse and complex; this requires a logical generalization of numerous objects from the particular to the general to summarize the general laws governing the development and change of the real world.

To correct Hegel's "idealist starting point and the arbitrary fabrication of a system regardless of the facts," and to achieve a thorough critique of Hegelian dialectics, Engels adopted a more direct method in the process of creating materialist dialectics. This method was to "start from empiricism and materialism" and to "deduce the universal from the particular." This is an inductive reasoning method with materialist attributes. Inductive reasoning is not necessarily true in the same way as deductive reasoning, but it can yield new knowledge; the dialectical attributes of nature are precisely the new knowledge derived from such reasoning. If the materiality of the world "is proved not by a few juggled phrases, but by a long and wearisome development of philosophy and natural science," then the concrete state of existence of the material world likewise requires the long and continuous development of philosophy and natural science to be proven. It was precisely due to natural scientific discoveries such as the law of the conservation and transformation of energy, cell theory, and the theory of biological evolution that "the whole of nature is revealed to us as a system of connections and processes, at least in its main features, explained and understood." Only by fully absorbing the theoretical achievements of natural science and deeply mastering the laws of motion in nature could Engels form the grand idea of the world as a complex of processes and confirm the essential characteristics of universal connection and motion-development.

To establish dialectics on a more solid natural scientific foundation, Engels closely followed the latest progress of 19th-century natural science, conducting philosophical research in numerous fields including mathematics, physics, chemistry, geology, biology, and physiology. Engels engaged in the study of the philosophy of nature to master dialectics and establish a scientific view of nature. His research path moved from empirical science to logical generalization in theoretical philosophy. Evaluation of the resulting dialectics and view of nature should be seen as a standpoint and method for guiding empirical scientific research. It cannot replace scientific theory in investigating the basic laws of connection and development in nature. If this is not recognized, one might make "overstepping one's bounds" ^[14] demands of the dialectics of nature, and thus fail to correctly recognize its true value. With the development of the times and scientific progress, some of the natural scientific philosophical issues discussed by Engels in Dialectics of Nature may have become outdated, but the value of his thought cannot be denied. What today's scholars need to do is master materialist dialectics and the dialectical view of nature to investigate and solve the natural scientific philosophical problems of their own era, achieving the innovative development of dialectics and the view of nature in the process of problem-solving.

3. Dialectics is a Scientific Theory Comprising the Three Laws and Related Categories

Hegel possessed rich dialectical thought, but it was embedded within an idealist philosophical system. After several years of concentrated research following his move to London, Engels began to summarize the laws of dialectics in his "1878 Plan." In the article "Dialectics" written in 1879, he further clearly expressed the content of the three laws: "the law of the transformation of quantity into quality and vice versa; the law of the interpenetration of opposites; the law of the negation of the negation." The basic ideas of these three laws had already appeared in Hegel, but because "Hegel developed them in his idealist fashion as mere laws of thought," they were only laws of thought and not laws of dialectics—not general laws within the realms of nature, human society, and thought. While sharply criticizing the utopian and mystical nature of Hegelian dialectics, Engels also affirmed that "Hegel, in hundreds of passages, is able to provide from nature and history the most convincing examples in proof of the laws of dialectics." It was precisely from examples in nature and history that Engels generalized and formed the laws of dialectics, allowing dialectics to appear for the first time in the form of a scientific theory. "The perspective on the three main laws of dialectics is not only a creative contribution but also laid an important cornerstone for the scientific system of dialectics." From the perspective of content, the three laws proposed by Engels constitute a critical inheritance of Hegelian dialectical thought; from the perspective of the system, they represent a thorough transcendence of Hegelian dialectics. Since then, dialectics has no longer been a spontaneous existence subordinate to reason, but has become a scientific theory for humanity to understand objective objects.

Hegel regarded the problem of the relationship between quantity and quality as a concept—

Within the sphere of "Being" ^[15], the movement of transformation between "quantity, quality, and measure" occurs at the stage of the immediacy of the Idea, a stage where the Idea exists in an undifferentiated, nebulous state. So-called "Being" refers to existing things and immediate things; for Hegel, this "Being," which originally possessed objectivity, represents the lowest stage of the Idea. Stripping away this idealistic content, Hegel’s exposition on quantitative change, qualitative change, and their relationship is accurate and brilliant. Engels extended the essence of these arguments to a broader field—to all objects in nature and human society—discussing the law of the transformation of quantitative into qualitative change in a general sense. Engels wrote: "In nature, qualitative changes—occurring in each individual case in a strictly determined way—can only take place through the quantitative addition or subtraction of matter or motion (so-called energy)." He also used the example of the comparative combat effectiveness between French cavalry and Mamluks ^[16] to illustrate the law of quantitative and qualitative change, thereby proving that this law likewise exists in the socio-historical realm.

Engels explicitly pointed out that the "law of the interpenetration of opposites" occupies an important position in Hegel. Hegel primarily discussed this law in the "Doctrine of Essence" ^[15] section of the concept, arguing that "Essence is past Being" and "Essence is reflected Being." Essence itself will undergo the stages of "identity," "difference," and their unity, i.e., "ground." When the concept transcends "Being" and enters the stage of "Essence," the thing itself becomes differentiated; that is, opposition arises within identity, and the unity and differentiation of essence and appearance emerge—essence is contained within, while appearance is manifested without. In analyzing the process of the connection and transformation between the essence and appearance of things, Hegel introduced a series of basic categories through methods of interconnection and transition, such as content and form, whole and part, internal and external, reality and possibility, contingency and necessity, etc. These basic categories all follow the principle of the unity of opposites and serve as annotations and interpretations of "essence." In order to connect the quantitative and qualitative changes of "Being" with the unity and differentiation of "Essence," and to endow each of these links with the momentum for continuous advancement, Hegel emphasized the concepts of negation and the negation of the negation. Negation here is dialectical negation—a negation formed by the development of objective things themselves. In the process of the self-negation of the negation, things acquire inexhaustible momentum for development. Although Hegel revealed the critical role of the unity of opposites in the development of things, he still treated the negation of the negation as the "fundamental law for constructing the entire system," integrating the latency of contradiction, the unfolding of contradiction, and the unity of opposites into a conceptualized, formalized negation of the negation through the triad of thesis, antithesis, and synthesis.

Engels explicitly proposed that the "law of the interpenetration of opposites" reveals the content of the differences, changes, and development of things themselves, and is the essence of the rational kernel of Hegelian dialectics. Only by explicitly revealing and highlighting this can the mystical form of idealistic dialectics be truly overcome. In Engels’s view, it is precisely contradiction that causes development; he believed that "there is a contradiction objectively present in things and processes themselves, and moreover, it is a real force." However, he had not yet elaborated on "contradiction" as an independent philosophical concept, but rather viewed it as a dialectical relationship. When one investigates things from the perspectives of motion, change, life, and mutual interaction, one finds the existence of "this-and-that" ^[17] contradictions. Not only does simple mechanical displacement contain contradictions, but organic life and its development contain them even more. Objectively speaking, Engels had not yet completely overcome the influence of Hegelian dialectics; his expression of the law of the unity of opposites was still subsumed within the law of the negation of the negation. In his works, there is no independent text regarding the law of the unity of opposites; the elaboration of this thought appears in the "Dialectics. Negation of the Negation" chapter of Anti-Dühring and in the notes and fragments of "Laws and Categories" in the Dialectics of Nature. In the chapter "Dialectics. Negation of the Negation," when Engels summarized and evaluated the intellectual processes of Rousseau and Marx, he still attributed them to the negation of the negation, writing: "a process which is antagonistic in its nature, full of contradictions, the transformation of one extreme into its opposite, and finally, as the kernel of the whole process, the negation of the negation." The negation of the negation is merely the form of the process, not its kernel; negation is the result of the antagonistic contradiction of things, not the cause. Engels gradually came to realize this. In the "1878 Plan" written after Anti-Dühring, he explicitly proposed "development caused by contradiction or the negation of the negation—the spiral form of development." However, this writing plan was never completed, and he was unable to carry out a profound elaboration of this newly proposed, correct viewpoint.

3. Clarifying the General Composition of Dialectics Based on the New Worldview

Engels proposed a theory of general dialectics primarily on the basis of studying the dialectics of nature, yet he did not limit his narration of dialectics to the natural world. Instead, he elaborated on the general composition of dialectics from the high level of the unity of nature and human society. In Engels's view, the dialectics of nature and the dialectics of history stand in a relationship of the unity of opposites: the opposition is reflected in their presentation in different fields, while the two are unified in materialist dialectics. The dialectics of the objective world is the foundation of human cognition and thinking; human thought must achieve identity with objective dialectics. People should continuously deepen the research on the laws of motion of the material world to achieve mutual promotion and common development between scientific theory and dialectics.

1. The Opposition and Unity of the Dialectics of Nature and the Dialectics of History

For a long time, many scholars have viewed Engels's dialectical thought as the "dialectics of nature" and Marx's dialectical thought as the "dialectics of history," and in this rigid, comparative severance, they have disparaged Engels's dialectical thought. For instance, Lukács believed that factors such as the interaction between subject and object, the unity of theory and practice, and the mutual influence of history and thought are the decisive elements of dialectics, and since these factors do not exist in nature, he questioned Engels's dialectical thought. Schmidt, a representative figure of the Frankfurt School, held a similar view, arguing that Engels's expansion of dialectics to the external natural world "exceeded the scope of Marx’s explanation of the relationship between nature and socio-history, and regressed into dogmatic metaphysics." The American scholar Levine pointed out even more directly that Engels explained dialectics as the laws of matter itself, excluding the Hegelian sub-obj opposition: "The dialectical system he contemplated exists as a description of materialistic monism of motion." In the eyes of these scholars, Engels took the whole of nature as his object of study, and the dialectics of nature he researched only established a materialist view of nature, which ran counter to Marx's sublation of traditional metaphysics through material practical activity, representing a retreat toward traditional metaphysics. These scholars' interpretations are incorrect; they find it difficult to understand the significance of the study of the dialectics of nature for the construction of materialist dialectical theory, nor do they correctly understand the premise of the dialectics of nature's argument—a point that has been elaborated in detail previously. What needs to be emphasized here is that the dialectics of nature and the dialectics of history are not two different kinds of dialectics; they both belong to materialist dialectics and are concrete manifestations of materialist dialectics in different fields. Although Marx's dialectical thought is mainly reflected in the socio-historical field, he never denied the existence of dialectics in nature. In a letter to Engels on June 22, 1867, Marx stated that Capital "quotes in the text the law discovered by Hegel of the transformation of merely quantitative into qualitative change, regarding it as a law equally valid in history and in natural science." If Marx did not acknowledge the existence of dialectics in nature, he would surely have discouraged Engels's decade-long research into the dialectics of nature. Both Marx and Engels regarded the study of the dialectics of nature as a necessary and rational division of labor.

What must be further asked here is whether Engels possessed thoughts on the dialectics of history and how he handled the relationship between the dialectics of nature and the dialectics of history. In fact, whether in co-authoring The Holy Family, The German Ideology, and The Communist Manifesto with Marx, or in interpreting Marx's thoughts on political economy, or in his later years defending Marxist philosophy and explicating historical materialism, Engels demonstrated rich thoughts on the dialectics of history. In the book review he wrote in 1859 for Marx's A Contribution to the Critique of Political Economy. Part One, Engels fully affirmed the historical thinking in Hegelian dialectical thought, praising Hegel's conception of history as "the direct theoretical premise of the new materialist worldview, and by virtue of this conception of history alone, a starting point was provided for the logical method." Engels was not only well-acquainted with the dialectical attributes of socio-history but also consciously used dialectics as a tool to analyze the development of human society. Therefore, the view accusing Engels of lacking or neglecting the dialectics of history is untenable. Some scholars have pointed out that the "nature" Engels studied was not a purely self-subsistent nature, but a humanized, industrialized nature—a nature marked by the imprint of human practical activity. Other scholars believe that "the dialectics of subject and object, with the dialectics of man and nature at its core, is the implicit theme of Engels's dialectical thought." These views all attempt to interpret Engels's thoughts on the dialectics of nature from the perspective of the subject-object relationship, highlighting the essential characteristics that the dialectics of nature should possess, and are worthy of affirmation. However, from the text of the Dialectics of Nature, his research objects did indeed include nature in itself, and what he sought to reveal included the dialectics of "pure nature" without the intervention of man as a subject. The article "The Part Played by Labour in the Transition from Ape to Man" emphasizes that it was only hundreds of thousands of years ago, in the geological epoch called the Tertiary period, that anthropoid apes appeared, and then gradually transformed into humans through upright walking and labor. Only then did man emerge as a subject. How, then, are we to understand the dialectics of nature existing in a self-subsistent way before the birth of man? Nature in itself without the existence of man certainly involves no dialectics in a formal sense, because what it represents is merely the state of the world's existence; without man as a reference point, there is no "development" or "evolution" [in a teleological sense]. That is to say, the evolution of the world, especially the development of things from lower to higher stages, takes man as the reference system. Natural science reveals the objective evolutionary process of things, while dialectics endows this objective evolutionary process with evaluative color and the meaning of progress. Therefore, the key to the problem does not lie in confirming that man must be present in nature, but in situating the existence of nature within a relationship of the unity of opposites with man. Dialectics must certainly reveal the relationship between the actual subject and object, but it must also reveal the relationship between subject and object in the historical dimension, revealing the relationship between the history of nature's existence and development and man. In this way, the dialectics of self-subsistent nature manifest with the birth of man; the emergence of man confirms the existence and value of the dialectics of nature.

In "The Part Played by Labour in the Transition from Ape to Man," Engels scientifically elaborated the transition from nature in itself to human society, constructing a bridge connecting "nature" and "society." At the same time, he endowed "nature" with historical attributes, because the appearance of man ensures that nature is no longer self-subsistent "pure" nature; no matter how long an evolution it had previously undergone, it presents meaning and value due to the existence of man and human society. The history of animals and plants is merely biological history; for the animals and plants themselves, this history was created for them, created by man [as an observer/categorizer], whereas once man was born, he began to create his own history, and in the process of creating his own history, formed the history of the world. It is precisely because of the existence of man that the entire world has a history and thus possesses the attributes of dialectics. Engels never imposed dialectics upon nature; the dialectics of nature he revealed is the state of development that nature presents relative to man. Even if actual man was not present within nature [historically], nature nonetheless always takes actual man as its reference. The dialectics of nature and the dialectics of history are one, unified within materialist dialectics.

2. The Demarcation and Identity of the Dialectics of the Objective World and Human Thinking

The most direct conclusion Engels reached through his study of the dialectics of nature was that dialectics exists in the objective world. However, he did not limit himself to discussing dialectics within the objective world, but instead expanded the problem-domain inversely into the realm of human thinking. Before explicitly proposing the three laws of dialectics, Engels wrote:

"The laws of dialectics are abstracted from the history of nature and the history of human society. They are nothing but the most general laws of these two aspects of historical development, as well as of thought itself." This formulation by Engels first demarcates the domains of dialectics: it exists both in the objective world (including nature and human society) and within human thought. Simultaneously, it clearly reveals that the dialectics of the objective world and the dialectics of human thought stand in a relationship of "prior and posterior." Although the dialectics of the objective world possesses priority and determinacy, the dialectics of human thought possesses agency, in that "the human mind can apply these laws consciously." Breaking down the division between the objective world and human thought expands the necessary space for practice for the human being as a subject, while human practice in turn constitutes the necessary prerequisite for the identity of the two.

In Hegel, dialectics exists in only one form—the dialectics of the Idea ^[18]. That is to say, dialectics has only one subject, the Idea, which ultimately reverts to human thought. Engels, however, rationally demarcates dialectics, clarifying two forms of dialectics that share the same attributes and pointing out that dialectics has two subjects: the objective world and human thought. By comparison, Engels's approach is more consistent with the essential attributes of dialectics. Because dialectics itself emphasizes opposition and difference—being the fundamental law regarding the unity of opposites—Engels’s scientific distinction restores the contradictory attributes that dialectics ought to possess. Engels once explicitly noted that Marx was "the first to bring once again to the forefront the forgotten dialectical method, its connection with Hegelian dialectics, and its differences from it." However, Marx delved directly into the realm of social history, treating dialectics as a cognitive tool for the analysis of political economy, without offering an exposition on how dialectics could become a tool of human thought in the first place; this foundational work was completed by Engels.

Engels argued, first, that both subjective thought and the objective world follow dialectics. The laws of motion in the objective world and the laws of motion in human thought are consistent and essentially identical; ultimately, the results of the two are not contradictory but coincide with one another. "This fact is the unconscious and unconditional prerequisite for our theoretical thinking." Human theoretical thinking is possible because both subjective thought and the objective world follow the same laws—namely, dialectics. Human thought should follow dialectics to achieve consistency with the objective world; this unity does not shift according to human will, nor does it require any prerequisite conditions. Second, subjective thought should actively master dialectics. The unity of subjective thought and the objective world is characterized by dynamism and difference, manifesting as an infinite process of transformation from relative truth toward absolute truth. The theoretical thinking of every epoch is a historical product, taking on entirely different forms and contents in different eras. "The theory of the laws of thought is by no means an 'eternal truth' completed once and for all, as the philistine’s brain imagines when it hears the word 'logic.'" Dialectics as a scientific theory is not an "eternal truth," but rather the subjective mind's never-ending exploration and pursuit of the dialectics of the objective world. Third, subjective thought necessitates the strengthening of the construction of logical theory. Although Engels did not explicitly propose the thesis of the unity of dialectics and logic, he believed that modern philosophy had already become a realm of pure thought—a "doctrine of the laws of the process of thought itself, i.e., logic and dialectics." Dialectics as subjective thought should possess a complete form of expression, and this form is the theory of dialectical logic. The theory of dialectical logic allows the content of objective dialectics to be fully displayed; dialectics should be the organic unity of a worldview with logic, mediated by epistemology.

3. The Mutually Reinforcing Relationship Between Dialectics and Scientific Theory

The greatest difference between Marxist dialectics and Hegelian dialectics lies in their worldviews. This difference is first reflected in the distinction between materialism and idealism: Marxist dialectics is materialistic in form, while Hegelian dialectics is idealistic. The former manifests as a mutually reinforcing relationship between dialectics and scientific theory, whereas the latter manifests as mysterious dogmatism and metaphysics.

The series of major scientific discoveries achieved in the natural sciences during the 19th century served as the foundation and prerequisite for Engels’s research into dialectics. It was precisely these new scientific discoveries that struck a blow against various anti-dialectical and anti-materialist mystical views. "Under the onslaught of science, one division after another laid down its arms, one castle after another surrendered, until finally the infinite realm of nature was conquered by science, leaving no foothold for the Creator." In Engels’s view, modern materialism has at least two theoretical prerequisites: first, natural science, which reveals the laws of the motion of matter; and second, philosophy, which further reveals the internal connections between the natural sciences. This philosophy is primarily manifested as dialectics. Natural science, in turn, is an important prerequisite for dialectics. By adopting a subject-object opposition model to study and explore natural phenomena, natural science arrives at the essential laws of the connection, motion, and development of things, providing the material basis and theoretical prerequisite for the formation of dialectics. Engels’s dialectical thought was formed precisely on the basis of fully absorbing and drawing upon the nutritional elements of scientific theory.

However, natural science theories reflect the cognition and grasp of the laws of motion in a specific area or level of nature by people in a particular era. As research expands and deepens, people discover new laws of motion and propose new scientific theories. Engels deeply recognized this, noting: "We can only know [nature] under the conditions of our epoch, and to the extent that these conditions allow." Limited by the conditions of the era, the truth-status of natural science exhibits characteristics of relativity; thus, "eternal laws of nature are increasingly becoming historical laws of nature," as new scientific theories are constantly discovered, correcting or even replacing existing ones. What is the relationship between dialectics and these new scientific theories? Must dialectics also be replaced as scientific theories are updated? In fact, dialectics is the revelation of the deeper-level essential laws of nature. It is a philosophical theory established above the various branches of natural science. The internal turnover of scientific theories does not lead to the collapse of the dialectical system; on the contrary, new scientific discoveries further confirm the scientific attributes of dialectics. For instance, in a letter to Marx on May 30, 1873, Engels expressed the idea that matter and motion are inseparable. This concept of the motion of matter transcended the scope of classical mechanics and was later proven by the 20th-century discoveries of relativity and quantum mechanics. Furthermore, by mastering and applying the principles of dialectics, Engels made predictive judgments about natural science—for example, that atoms "have complex components," that matter is "hierarchical," and that "new marginal sciences" would inevitably emerge at the junction of various disciplines. These views have all been confirmed one by one. Simultaneously, progress in scientific theory continuously replenishes and enriches the composition of dialectics. For Engels, dialectics is absolutely not some new "metaphysics" or an absolute theory, but a scientific theory that needs constant enrichment and refinement. Dialectics itself is derived from nature and elucidated starting from nature; progress in scientific theory signifies the deepening of human understanding of natural laws. New insights naturally need to be absorbed into dialectical theory, and the progress of scientific theory will inevitably promote the development of dialectics.