G.W.F. Hegel’s Science of Logic (1812-1816) is a vast treatise on the nature, origin, extent, and forms of conceptual thought. Hegel describes the formation of concepts as a process by which being emerges as essence and essence emerges as a concept. Hegel also describes the stages by which concepts are determined, and he explains how the Concept or Notion reveals the unity of essence and being.

The Science of Logic is divided into two volumes: Volume One is "The Objective Logic," and Volume Two is "The Subjective Logic, or the Doctrine of the Notion." Volume One consists of two books: "The Doctrine of Being" and "The Doctrine of Essence." Volume Two consists of three sections: "Subjectivity," "Objectivity," and "The Idea."

Hegel defines logic as a science of pure thought concerning the rules or principles by which concepts are formed. Logic is divided into: (1) objective logic (the logic of the Notion as Being), and (2) subjective logic (the logic of the Notion as Notion).¹ Objective logic is concerned with how being and essence become the source of the Notion. Subjective logic is concerned with how the subjective Notion develops into the objective Notion.

Hegel says that logic may also be divided into three parts: (1) the logic of being, (2) the logic of essence, and (3) the logic of the Notion.² Logic reveals the principles of pure knowing, in which there is a unity of subject and object. Pure knowing has a simple immediacy, in contrast to the knowing that is mediated by reflection. Pure knowing reveals the ultimate truth of the Idea, which is the objective and adequate Notion.

According to Hegel, being may determine itself in three ways: (1) as determinateness (quality), (2) as sublated determinateness (magnitude, or quantity), and (3) as qualitatively determined quantity (measure).³ Pure being is an indeterminate and undifferentiated immediacy, and is therefore an empty abstraction. Pure being has the same absence of determinateness as pure nothing. Thus, pure being is the same as pure nothing. Pure being is lacking in any defining quality. Determinate being is what defines reality, and reality is a defining quality of determinate being.

Hegel also says, however, that it may be argued that pure being is not the same as pure nothing.⁴ Being and nothing may be moments (or stages) of a process of becoming. Being and nothing may be moments of a transition of being into nothing or nothing into being. Being and nothing may be vanishing moments of becoming. Becoming may be the vanishing of being into nothing or nothing into being.

He argues that determinate being begins through a process of coming-to-be or ends through a process of ceasing-to-be, and that both of these processes are moments (or stages) of becoming. Determinate being (or determinate non-being) is concrete, while pure being (or pure non-being) is abstract. Determinate being is reality, while indeterminate being is an empty abstraction.

Determinate being may have moments of being-in-itself or of being-for-other. Being-in-itself determines itself only in relation to itself, but being-for-other determines itself in relation to something other than itself. Being-for-other has otherness within itself, but being-in-itself is withdrawn from otherness. Thus, being-in-itself is also the non-being of being-for-other.⁵

Hegel also says, however, that the being of things in themselves, insofar as it is assumed to be devoid of all being-for-other, is an empty abstraction. The being of things in themselves cannot be known if it is empty of any being-for-other. The being of things in themselves is actually the being of their Concepts or Notions. The Notion is a unity of being-in-itself and being-for-other.

The Notion is being-for-itself. Being-for-itself transcends otherness and is absolute being. Being-for-itself is the One that gives rise to the many. Being-for-itself may have a moment of determinate being as being-for-one. Being-for-one is a self-determination of being-for-itself. The One unifies being-for-one with itself, and it is infinite being.

The Void is the negation of the One. The Void is absolute non-being. The Void is the nothing that may be posited as the vanishing of the One. However, the Void is also the nothing that may be posited as the first stage of the becoming of being. Thus, the Void and the One are moments of becoming of being-for-itself.

The One is a unity of the many ones. The many ones may attract or repel each other, according to whether or not they are posited as determinations of the One. The many ones that have been posited as determinations of the One are attracted to each other, but the many ones that have not been posited as determinations of the One are repelled from each other. The One attracts the many ones that it has posited, but it repels the many ones that it has not posited. The truth of the One and the many is therefore a process of attraction and repulsion that produces a dynamic unity.

Hegel defines magnitude (or quantity) as the sublated determinateness of being. Pure quantity may be distinguished from determinate quantity. Pure quantity is sublated being-for-itself, but determinate quantity (or quantum) is a unity in which being-for-itself and being-for-other are both sublated. Pure quantity is not confined by limits, but determinate quantity is confined by limits. Pure quantity is continuous, but determinate quantity is discrete.

According to Hegel, space and time are examples of pure quantity.⁶ Finite numbers and limits are examples of determinate quantity.

Hegel therefore declares that a quantum is a determinate quantity, and that it may differentiate itself into: (1) an extensive quantum (having a limit in a determinately existent plurality) or (2) an intensive quantum (having a limit in its own being-for-itself).⁷ Quantum as number is a complete determinateness of quantity, and it includes many ones within its own being. An extensive quantum may be posited as a number, but an intensive quantum may be posited as a Notion of itself.

Hegel also explains that measure is a qualitatively determined quantity, and that it is therefore a unity of quantity and quality. Measure is a quality that has a determinate quantity. The measureless has a quality that cannot be determined as a quantity.

Hegel also distinguishes between the qualitative infinite, in which the finite vanishes into the beyond, and the quantitative infinite, in which the quantum progresses continuously into the beyond.⁸ The quantitative infinite may be sublated by or may become the qualitative infinite.

According to Hegel, being may determine itself as indifference before it sublates itself in the process of becoming an essence. Indifference is a quality of being open to all determinations. Indifference may appear when external differences are indistinguishable from each other.

Essence is a mode of being-in-and-for-itself. Essence is also an absolute sublation of otherness. Absolute essence is indeterminate, but it may emerge into determinate being. Being may become essence, and essence may become the Notion.

The differentiation of the essential and the unessential is important for determinate being. Illusory being is unessential and has nothing as its essence. Illusory being is without essence and is the negation of essential being. Thus, illusory being is also the non-being of essential being. However, essence in itself is the non-being of being insofar as it is not the same as being. Essence may be a transitional moment between being and the Notion. Essential being is therefore in-and-for-itself.

Hegel describes the determinations of reflection as including: (1) the Law of Identity (that everything is identical to itself, or that A=A), (2) the Law of Contradiction (that a logical proposition cannot be both true and false, or that A cannot at the same time be A and not-A), and (3) the Law of the Excluded Middle (that a logical proposition must be either true or false, or that there is nothing that is neither A nor not-A).

He also emphasizes that contradiction should never be dismissed as meaningless or unreal, and that contradiction is inherent to the nature of being. Every determinate thing or Notion is a unity of distinct moments that are different and therefore contradictory. Finite being is inherently self-contradictory, and it must return to its ground in absolute being, in which all contradictions are resolved.

Hegel explains that the determinations of reflection include the Law of Ground (or Sufficient Reason), according to which everything must have a sufficient ground. Absolute ground is the ground of all being. Any determinate ground is ultimately grounded in the Absolute. Absolute ground is undetermined by any other ground.

Determinate ground has a determinate form and content. Thus, Hegel argues that a determinate ground is sufficient if it is equal in form and content to the thing or being for which it is the ground. The determinate ground includes: (1) the formal ground, (2) the real ground, and (3) the complete ground.

The conditions for something are not the same as its determinate ground. The determinate ground has its own conditions and is itself conditioned. The ground may be part of the conditions for something. The ground-relation may be a conditioning mediation for the becoming of something. The ground for something is presupposed by the conditions for that thing. However, the absolute ground is unconditioned by any other condition and is its own condition.

Being and existence may be essential or unessential, according to whether or not they are the becoming of essence. Essential being is the becoming of the essence of something, but unessential being is not a becoming of the essence of something. Appearance is a posited mode of being that may be essential or unessential. Appearance may be the essential existence of something, and it may therefore be distinguished from illusory being. Illusory being is essenceless being or the unessential existence of something.

Appearance as the essential existence of something may be posited in relation to an essential ground. Appearance as a determination of an essential unity may fall to the ground or withdraw into the ground. Thus, Hegel explains that the essential world or world in-and-for-itself may be the ground of the World of Appearance.

The Law of Appearance, according to Hegel, is the relation between the essential world and the World of Appearance. The Law of Appearance is a relation by which Appearance unifies itself with its other. The World of Appearance may be reflected by an other, but the other may also be reflected by an other, and thus the World of Appearance may have an essential self-relation that becomes a Law of Identity. The Law of Appearance is therefore a unity of manifold determinations by which the World of Appearance and the World of Otherness are posited as each other.

Hegel argues that being is unreflected immediacy, but that essence is reflected immediacy.⁹ Being may be reflected as a moment in the becoming of essence. Becoming is therefore a mediation of being. Being and essence may be moments of becoming of the Notion. The Notion manifests the implicit nature of substance, which is the unity of being and essence, and which is immediate actuality.

Being may have actuality, possibility, or necessity. Through the determinations of reflection, formal being may become real being. Formal actuality is immediate and unreflected, but real actuality is a unity of immediacy and reflection. Formal possibility is indeterminate and unreflected, but real possibility is determinate and reflected. Formal necessity is indeterminate and without content, but real necessity has a determinate content.

According to Hegel, the relation of causality includes: (1) formal (posited) causality, and (2) real (determinate) causality. A cause is formal or real only insofar as it produces an effect. Therefore, an effect implies a cause, and a cause is implied by an effect.¹⁰

The Notion may be formal, subjective, or objective. The subjective Notion may be a judgment or syllogism (rational Notion). The objective Notion is attained by the dialectical progression of these moments of the subjective Notion, and it therefore reveals a unity of judgment and reason.

Hegel explains that the Notion may have moments of universality, particularity, or individuality. The universal Notion is absolutely infinite and unconditioned. However, the universal Notion includes differentiation and determinateness within itself. The universal Notion has the creative power to determine itself freely and to differentiate itself internally.

He agrees with Kant that the unity of Concepts or Notions is the original synthetic unity of apperception (or self-consciousness). Freedom belongs to the Notion as the "I" or pure self-consciousness. He disagrees with Kant, however, that the Notion of the "I" is provided by the "I" as an object of intuition. He argues instead that the Notion of the "I" or ego is a Notion of the "I" as a being-in-and-for-its self. This being-in-and-for-itself is the unity of apperception.

Hegel criticizes the tendency of other philosophers to classify Concepts or Notions as clear or obscure, distinct or indistinct, adequate or inadequate. He says that these classifications are arbitrary, and that all Notions are determined by the same absolute Notion.

A judgment is a realization of a Notion, and it consists of all the determinations that are posited in the Notion. Judgments of existence include positive, negative, and infinite judgments. Judgments of reflection include singular, particular, and universal judgments. Judgments of necessity include categorical, hypothetical, and disjunctive judgments. Judgments of the Notion include assertoric, problematic, and apodictic judgments.

A syllogism is a logical argument whereby reason discovers the determinate unity of the Notion. Forms of the syllogism include: (1) the syllogism of existence, (2) the syllogism of reflection, and (3) the syllogism of necessity. The syllogism of existence reveals a truth about something that exists. The syllogism of reflection may take the form of the syllogism of universality, the syllogism of induction, or the syllogism of analogy. The syllogism of necessity may take the form of the categorical syllogism, the hypothetical syllogism, or the disjunctive syllogism.

Hegel argues that objectivity is the absolute being of the Notion. The objectivity of the Notion includes: (1) the mechanism by which its moments have an inner and outer unity, (2) the interaction by which the self-subsistence of these moments is sublated, and (3) the teleology by which the unity of the Notion becomes a purpose or goal. Thus, the subjective Notion may become an objective Notion, and its subjective unity may develop into an objective unity.

The Idea, as defined by Hegel, is a unity of the subjective and objective Notion. The absolute Idea is also a unity of the theoretical and practical Idea.¹¹ The absolute Notion or Idea may develop by a process of resolving moments of contradiction. Dialectic as a necessary function of reason belongs to the objectivity of the Notion, and is thus the becoming of the absolute Idea.

Hegel’s Absolute Idealism affirms that the absolute Idea is the underlying reality or ground of all being. The absolute Idea is ultimate reality. The Idea is a dialectical unity of the subjective and objective Notion. The absolute Idea is a unity of the subjective and objective Idea. Being and essence are true and actual insofar as they express the Idea. The Ideal is infinite, and infinite reality belongs to the absolute Idea.

¹G.W.F. Hegel, Science of Logic, translated by A.V. Miller (London: George Allen & Unwin, Ltd., 1969), pp.60-1.
²Ibid., p. 64.
³Ibid., p. 79.
⁴Ibid., p. 83.
⁵Ibid., p. 120.
⁶Ibid., p. 189.
⁷Ibid., p. 202.
⁸Ibid., p. 372.
⁹Ibid., p. 530.
¹⁰Ibid., p. 559.
¹¹Ibid., p. 824.

Hegel, G.W.F. Science of Logic. Translated by A. V. Miller. London: George Allen & Unwin, Ltd., 1969.