The Historical Development of Philosophy

New Philosophy

The Philosophy of Enlightenment and Its Opponents

Philosophical worldviews that prevailed throughout the 18th century until its end bear the name of Enlightenment philosophy in a dual sense, embodying the spirit of their time. They aspire to be enlightened by seeking clear and comprehensible explanations for the problems of existence; they strive to enlighten others, wishing to disseminate knowledge that is useful and worthy of study to aid the education and well-being of society. The philosopher most resolutely meeting this need from the preceding period is John Locke. His teachings are simple, clear, and understandable to human reason: they represent the finest expression of the dual notion of enlightenment. Consequently, Locke’s philosophy predominantly reigns over all others during the Age of Enlightenment. Locke largely shaped the philosophical movement in England and France, while in Germany, the philosophy of Leibniz began to gain influence, aligning with Locke’s tendency to make philosophy practical. However, at that time, Leibniz was known primarily through his popular writings, chiefly theological and teleological, allowing his philosophical contributions to be easily connected to Locke's teachings within a singular eclectic philosophy. Thus, Enlightenment philosophy suffers from a complete lack of original ideas. The greater its cultural and historical significance, the less its value for the advancement of philosophical thought; rather, it served progress only indirectly, first by provoking opposition from individual profound minds and later, like any one-sided movement, inciting a general reaction against itself, which became the foundation for the development of the subsequent period. Therefore, if this philosophy arrogantly believed it and its time had reached the pinnacle of spiritual development, it is, from a broader perspective, merely a transitional epoch between the great systems of the 17th century and the new teachings of the impending 19th century. The most important representatives of this transitional period are predominantly the opponents of Enlightenment philosophy—individual thinkers who, while following the general direction of their time, forge distinct, relatively independent paths. In the struggle between Enlightenment philosophy and its adversaries, the conflict of worldviews from the previous period reemerges in a somewhat altered form, marking the formation of the great systems. This change in the nature of the struggle arises from a shift in perspectives and the emergence of new ideas within the opponents of Enlightenment, foreshadowing the coming epoch.

The development of Enlightenment philosophy begins in England, where Locke’s teachings exerted a direct influence and where Newton’s theory of universal gravitation, even against the will of its creator, contributed to the emergence of a purely mechanical idea of nature grounded solely in itself. However, the popularizing philosophers of the early 18th century, known as “free thinkers,” primarily embraced the religious-philosophical ideas of Locke. Yet while Locke, in his work "The Reasonableness of Christianity," attempted to harmonize the religious doctrines of positive Christianity with rational knowledge, the public activity of the free thinkers increasingly adopted an anti-dogmatic stance, as evidenced by the titles of their works: for instance, Toland's "Christianity Not Mysterious" (1696), Collins's "A Discourse on the Grounds and Reasons of the Christian Religion" (1724), and Tindal's "Christianity as Old as the Creation" (1730). Where these writers engage with theoretical questions, they are inclined to transcend the bounds of Locke’s teachings in a similar manner. Thus, John Toland (1670—1722) sketched an outline of a materialistic system, forming a connecting link between the older teachings of Thomas Hobbes and those of the later French Enlightenment. In opposition to the aspirations of such free thinking stands the principal philosopher of this epoch, George Berkeley.

Empiricism and Idealism of Berkeley

Berkeley’s philosophy acquires its unique character primarily through its outward opposition to the development of English Enlightenment, which finds its source in Locke’s philosophy, even as it arises from the very premises of Locke's empirical theory of knowledge. This circumstance can be partly explained by the cautious foresight with which Locke, unlike his followers, approached metaphysical questions, and partly by the dogmatic nature of his premises, which cannot be regarded as beyond doubt in all respects; these premises necessitated the introduction of certain assumptions to dispel such doubt by complementing experience. Locke’s system explicitly left open the possibility for such supplementation in two directions. On one hand, the equation of external and internal experience, sensations and reflection, could invite skepticism, as reflection, by its very name, is merely a consequence of preceding sensations. From this perspective, it was not difficult to arrive at the view that the ideas of reflection are merely simple transformations of the ideas of sensations, thereby reducing the entire content of knowledge to sensory impressions and the actions they evoke on the sensory faculties, actions that must themselves be conceived as mechanical. In this manner, a form of objectivism emerged, which for the free thinkers transitioned into a metaphysical materialistic worldview. On the other hand, the distinction between primary and secondary qualities could equally appear arbitrary. With the removal of this distinction, only one conclusion remains: to recognize the content of sensations not as actions of external objects on our senses but merely as representations that exist within us. Thus, subjectivism was born, leading to the outright denial of the objective existence of the material world and the acknowledgment of the spiritual realm as the only truly existent one.

In such a direction moved George Berkeley (1685—1753). Finding the distinction between primary and secondary qualities arbitrary and hence the recognition of sensations and reflections as two different sources of knowledge equally unwarranted, he posits the subjectivity of all experience. Subjective consciousness for him is the realm in which all thought operates; it is utterly incomprehensible how human consciousness might ever transcend the boundaries of its own awareness, thus rendering it impermissible to distinguish between the diverse contents of consciousness, whereby one must be subjective and another both subjective and objective. Berkeley attempts to empirically ground his understanding by demonstrating that all our sensory perceptions, such as our notions of magnitude, extent, and distance in visual images, are exclusively constructed from the connections of individual sensations, the existence of which outside us we have no basis to affirm. As experience consists solely of the concrete, while abstract concepts are mere fictions, names for the purposes of mutual understanding of numerous distinct objects, the same can be asserted about the concept of matter. Only our representations with their directly inherent properties—tactile, color, etc.—are real; matter itself is simply a product of conceptual construction.

Nevertheless, Berkeley asserts that the practical foundation for recognizing the world is given outside of our individual consciousness. This foundation lies in the perceptions of others with whom our own perceptions are in solidarity, and to whom our actions relate; it is reinforced by the idea of God, which we could not create in our own consciousness. This conception of a world outside of ourselves, which we can contemplate according to properties corresponding to the idea of God, would also be in harmony with the fact that our perceptions are in a lawful connection, whereby, since we relate them to real objects, they are identical to our neighbors' perceptions of the same objects. However, the only conclusion we can draw from this, according to Berkeley, is the existence of a spiritual world composed solely of the harmonious ideas of knowing entities, the creator of which we must recognize as God, who is directly present within us. Therefore, the only world that is truly real for us is the spiritual realm in which we ourselves live with our perceptions, and as its creator, we feel the presence of God within us. Yet, God's creative activity is not limited to a single initial act of creation; He is the eternal creator of this spiritual world, uniting us with our neighbors, which is why we must continually sense His creations within ourselves. Thus, Berkeley, from his subjective doctrine of knowledge, necessarily arrives at an idealist metaphysics that, in its views, is closest to occasionalism, which emerged somewhat earlier in the Cartesian school. Although, in justifying his doctrine, Berkeley rightly appeals to sound human reason, which assumes things to be precisely as his philosophy presents them, he cannot, of course, account for how to reconcile his views with the demands of natural scientific knowledge. Here, it is evident that Berkeley’s one-sided psychological perspective constrains his outlook. Given the predominance of natural scientific orientation during this time, it is quite understandable that his doctrine did not gain widespread acceptance and often led to a misunderstanding of his intentions: it was frequently believed that he wished to confine all knowledge to individual consciousness.

In France, where Cartesianism and scholasticism were still vying for dominance at the beginning of the 18th century, the acquaintance with Locke and Newton's natural philosophy had a liberating effect, chiefly owing to Voltaire (1694—1778). This acquaintance strongly supported the desire to liberate minds from the yoke of traditional prejudices—a desire that arose from the general conditions of the time. Under the influence of Locke's teaching, which posited that all knowledge arises from sensations, Newtonian gravity was reinterpreted into a purely mechanical worldview. Consequently, there was a rapid transition from empiricism to sensualism and from the latter to extreme materialism. While Condillac (1715—1780) sought to demonstrate vividly that all reflection arises from sensations and that therefore spiritual life ultimately relies on them, La Mettrie (1709—1751), drawing on his medical experiences, pointed to dreams and delirious states as evidence of the soul's complete dependence on brain states. Helvétius (1715—1771), from a similar perspective, developed primarily a moral philosophy, reducing all forms of pleasure to sensual enjoyment and all human striving to selfish motivations, which he advised should be tempered by education and prudent consideration of self-interest. The entire development of French Enlightenment, from skeptical empiricism to materialism, is reflected in the changes undergone by the views of Diderot (1713—1784); however, in his later works, he aligns himself with the prevalent moderate view that sensations should not be seen as mere products of material movements, but as a common property of atoms. Finally, the revolutionary tendency of this entire movement is clearly evident in the "System of Nature" (1777), which arose among radical free thinkers and was primarily authored by the German Baron d'Holbach (1723—1789), who lived in Paris.

French Enlightenment, like the English, found itself opposed; however, the struggle against it was conducted in a more fragmented manner. Its opponents generally agreed with the practical aims of the Enlightenment in demanding a complete reform of morals, the state, and society. These anti-materialist currents followed two directions. One, finding its inspired and eloquent advocate in Rousseau (1712—1778), sought to defend spiritual, primarily religious, interests against the tide of materialism. This current preached a Christianity devoid of dogma, grounded in natural sentiment and the three great components of the symbol of faith common to all religions: God, freedom, and immortality. It further called for a return to nature in all spheres, especially in education and moral life. Wishing to apply these ideas to the state, Rousseau in his "Social Contract," a democratic work akin in spirit to Thomas Hobbes's absolutist doctrine of the state, became a proponent of unlimited popular sovereignty and the absolute dominion of the general will, which, arising from the foundation of the state through the free will of all individuals, acquired power over the actions of each separate member through a social contract. With these political ideas, Rousseau prepared the ground for the forthcoming revolution far more than his materialist opponents did.

The second current, unfriendly to materialism, shared with it the general tendency of the Enlightenment. However, it regarded materialism, just as it did any metaphysics, as a system of concepts, partially dubious and partially full of contradictions: it saw the task of philosophy in investigating the principles of the exact sciences. The leader of this direction in the theoretical realm was d'Alembert (1717—1783), who was joined by great mathematicians of later times such as Lagrange, Laplace, and others; in the practical and sociological realm, Turgot (1727—1781), who saw the victory of natural science and industry as a sign of the new age. Both were heralds of positivism, which emerged later and achieved significant influence, first in the 19th century; their views, marked by a skeptical attitude towards all metaphysics, were related to the ideas proposed in England at the same time by David Hume, who, however, based his positions more on psychological foundations than on scientific ones.

In the preceding period, the oppositions between empirical and rationalist directions found a certain reconciliation in skepticism—an opposing direction to both; similarly, the philosophy of David Hume (1711—1776) revealed a critical and skeptical attitude toward the conclusions of dogmatic systems stemming from empiricism. Hume, like Berkeley, refuses to acknowledge the value of distinguishing between so-called primary and secondary qualities of sensations. Like the objective directions, he derives all ideas from sensory impressions; thus, he builds his theory of knowledge on a sensationalist foundation. However, he dismisses as unjustified any attempt to draw metaphysical conclusions from these premises. Consequently, the concept of God, as established by Berkeley, is for Hume just as much an unproven assumption as the notion of objective matter existing independently of us. We are presented exclusively with sensations and their various combinations. Thus, for Hume, the sole task of philosophy is to find the conditions under which we derive these combinations and then determine the actual content of the concepts characteristic of such combinations of our ideas, such as substance, causality, or, in the moral realm, sympathy, goodwill, and justice.

In this sense, Hume attempts to demonstrate that substance and causality are not objectively existing entities, nor are they a priori ideas; rather, they constitute, in their empirical content, mere associations formed through habitual combinations of impressions. Thus, for him, substance is a complex of impressions continuously linked into a singular unity, while causality is the sequence of impressions, where we designate what precedes as the cause and what follows as the effect. In parallel with these foundational concepts of theoretical knowledge, moral motives, according to Hume, also rely on the strength of customary associations. The most fundamental moral motive is sympathy for our fellow beings; it arises when we penetrate, through association, into the soul of another experiencing happiness or suffering. This moral theory, which posits sympathy as its foundation, was developed by Adam Smith (1723—1790), who sought to liberate it entirely from the rational foundations still intertwined with it by Hume, thereby transforming it into a pure moral sentiment.

Approaching any metaphysics with skepticism, Hume outlines, in essential terms, the critical task of philosophy in both the realm of epistemology and morality, a task that in each of these domains rests upon the psychological laws of association. Through this, Hume adopts the stance of a skeptical critic who, by consistently pursuing a purely empirical direction, primarily works toward the dismantling of dogmatic metaphysics; yet, at the same time, his endeavor to justify the origins of fundamental concepts in both knowledge and morality paves the way for critical philosophy.

On the other hand, a similar objective is pursued by the philosophical movement that developed in the eighteenth century in Germany, influenced by Leibnizian thought and English philosophy. Here, Christian Wolff (1679—1754), who dominated German scholastic philosophy until the century's end, transformed Leibniz's philosophy into eclecticism, which, in a metaphysical sense, essentially reverted to Descartes' dualism while experiencing significant influence from Locke’s teachings. Wolff reinstates the notion that it is, most likely, only humans who possess a soul, which is connected to the body at a specific point in the brain through a “pre-established harmony,” understood externally as a harmony predetermined by God. In other respects, he maintains that psychological phenomena can equally be deduced from the concept of the soul—a simple essence endowed with the capacities of representation and desire—as they can be inductively discovered through empirical observation. Therefore, Wolff discusses psychology from two perspectives: rational and empirical; however, in both rational and empirical psychology, instead of actual explanation, he merely subsumes under known species concepts the “capacities of the soul.” Alongside “rational psychology,” Wolff positions cosmology and rational theology, natural law, and so forth—disciplines of a dogmatic-syllogistic character, in which the striving to reconcile speculation and experience predominates. If in all this Wolff’s philosophy represents a synthesis of preceding systems undertaken in the interest of common sense, then in his teleological understanding of nature, Wolff closely aligns with Leibniz, although he transforms Leibniz's immanent purposes of nature into an external, anthropomorphic teleology, which henceforth dominates the entire philosophy of the German Enlightenment. From the standpoint of this philosophy, the measure for assessing things is the benefit they confer upon humanity: God has made man the center and ultimate purpose of His creation. In response to widely held views, this teaching facilitated the popularity of Wolff’s philosophy. In figures such as Reimarus, Mendelssohn, Garve, Nicolai, and others, it primarily directs itself toward moral, religious-philosophical, and aesthetic issues that ignite general interest. This direction also includes Lessing, who, more profoundly than others, grasped the essence of Leibniz's and Spinoza's thoughts, which lie between his own views.

However, alongside these popular philosophers aligned with Wolff and his school, there emerge thinkers who find the rational direction unsatisfactory and who, in contrast, regard feeling and immediate intuition as the ultimate sources of both empirical knowledge and belief in a supersensory world. Sensory perception, according to Hamann (1730—1788), rests no less on faith than Christian revelation. His ideas influenced Herder (1744—1803) and Fr. Heinrich Jacobi (1743—1819)—two principal adversaries of both Wolff's dogmatism and critical philosophy. Yet, this direction never reached a conclusive form in Germany. Its influence reflected only upon the thinkers of subsequent times.