Philosophy of the Modern Age and the Enlightenment

The Development of Rationalism

The rationalist movement in modern philosophy found its further development in the works of Benedict Spinoza (1632-1677), a prominent Dutch thinker and a younger contemporary of René Descartes.

Benedict Spinoza (Baruch de Spinoza) was born into a prosperous Jewish family in Amsterdam, which had been forced to flee from Portugal due to religious persecution by the Inquisition. He was educated at a Jewish community school, where the study of ancient Hebrew, the Bible, and the Talmud was customary. He continued his education in a Catholic school, where he studied Latin, philosophy, and the sciences. Late antique philosophy, the works of medieval Jewish thinkers, and the philosophical treatises of contemporaries such as Giordano Bruno, Francis Bacon, Thomas Hobbes, and René Descartes significantly influenced Spinoza's views. His independence of thought and unconventional interpretations of fundamental tenets of Judaism led to a confrontation with scholarly rabbis, culminating in his excommunication from the synagogue and expulsion from the community in 1656. Abandoned by family and friends, the thinker associated himself with Christians (though he did not become one), living a solitary life until his death in The Hague.

Spinoza’s principal works include "Ethics," "Treatise on the Improvement of the Mind," "Theological-Political Treatise," and "Political Treatise."

The direction of Spinoza's philosophical inquiries noticeably diverges from the central theme of modern philosophy—the investigation and understanding of nature for the purpose of subjugating and dominating it (nature-centeredness). While his concept formally continues Descartes' rationalism, its substance differs significantly. In Descartes' philosophy, the epistemological aspect prevails, while Spinoza is more concerned with practical philosophy—ethics.

Spinoza seeks not merely an impeccable methodology for grasping truth but a truth that reveals the meaning of human existence and guides individuals toward self-understanding and the pursuit of a higher good, the attainment of which is guaranteed to bring happiness. He posits that the ultimate aim of the philosophical path is to perceive the world and things “sub specie aeternitatis” (from the perspective of eternity) and to realize in life the ideals of wise conduct—impartiality and inner peace.

Spinoza's system of thought is articulated in his magnum opus, "Ethics." Striving for scientific rigor in the exposition of ideas, clarity, and precision in formulations, the philosopher employs a deductive-geometric method in composing the treatise. It begins with definitions of fundamental categories and self-evident axioms, followed by theorems with proofs, explanations, and necessary conclusions. According to Spinoza, this form of structuring a philosophical text aims to free it from abstractness, verbosity, and passionate-emotional interpretations of the subject.

The foundation of Spinoza's doctrine lies in a new concept of substance, which he defines as that which “exists by itself and manifests itself through itself.” Since substance—the primal foundation of the universe—requires nothing other than itself for its existence, it is “the cause of itself.” Substance is eternal because existence is inherent in its essence; it is free, as it exists and acts out of the necessity of its own nature.

The philosopher identifies substance with God, asserting that God is the only existing substance, as “everything that exists exists in God, and without God, nothing can either exist or be understood.” However, for Spinoza, God is not a personality. This is the God of the Bible, stripped of human qualities and characteristics (such as will and understanding).

Here, the philosopher follows the pantheism of Renaissance thinkers. God is “nature that produces” all that exists, while the created world is “nature produced.” Yet, God creates the world and things not as something distinct from Himself (as something other) but rather as the internally necessary (immanent) cause of the existence of all; He cannot be separated from the things that emerge from Him. Thus, all that exists is determined by the nature of God, and nothing exists by chance. The God of Spinoza is an impersonal absolute necessity, and the world is His necessary “consequence.”

“There is nothing in nature except substance and its manifestations,” Spinoza reiterates an ancient thought. The “manifestations” of substance include eternal “attributes” and finite “modes.” “Attributes” represent an infinite multitude of forms and shapes through which substance (God) expresses and reveals its essence. Of this multitude of attributes, humans are only aware of two—“thought” and “extension” (Spinoza reduces Descartes' two substances to attributes). The philosopher calls the countless states of substance “modes,” in other words, the multitude of diverse individual thoughts, ideas, bodies, and things of the created world. Since attributes express different aspects of God's essence (substance), they are equivalent; thus, a series of modes of one attribute precisely corresponds to a series of modes of another: “the order and connection of ideas is the same as the order and connection of things.”

According to Spinoza, the highest virtue of the human soul is the knowledge of God, for “the essence of our soul consists only in one knowledge, the beginning and foundation of which is God.” The philosopher distinguishes three kinds of knowledge: the first—the sensory level—is imagination or fantasy, where a person perceives the appearance of things, forming obscure, “inadequate,” often erroneous ideas. The second kind—reason or intellect—is when the soul can contemplate things clearly and distinctly; this level of scientific analysis grasps things “not as contingent but as necessary,... according to truth, that is, as they exist by themselves.” The third kind—the intuitive, the highest form of knowledge—perceives things as arising (“issuing”) from God.

A human being, like all that exists, is a part of nature and subject to its laws; hence, they must live and act according to natural necessity. Human activity is determined by a multitude of causes of which people are usually unaware, and thus they consider themselves free. The consciousness of most is occupied with their passions; while contemplating their sensations at the first level of knowledge, a person cannot ascend to its higher forms—reason and intuition. However, higher knowledge can liberate a person from the power of destructive passions; these are overcome by the more potent affect of joy derived from the very process of discovering truth. This emotional elevation Spinoza terms “intellectual love of God” and considers the highest good. Human freedom is the inner freedom from emotions and irrational actions; it is the mastery of oneself, the conscious necessity “to follow the order of nature,... which derives from the eternal determination of God.”

Spinoza himself affirmed the principles and rules of his teachings through the example of his life, leading a modest and temperate lifestyle, content with the bare necessities, refusing assistance from wealthy admirers. Being a well-known and respected philosopher, he earned his bread by polishing optical lenses, valuing his freedom and independence above all.

In the context of modern rationalism, the original teaching on substance—monadology—was developed by the prominent German philosopher and encyclopedic scholar Gottfried Wilhelm von Leibniz (1646-1716).

Gottfried Wilhelm Leibniz was born in Leipzig to a family of professors, studying philosophy and law at the University of Leipzig and mathematics in Jena. After completing his education, he chose a career as a diplomat and lawyer. From 1667 to 1672, he served the Elector of Mainz; from 1672 to 1676, he lived in Paris, where he became acquainted with prominent scholars such as Fermat, Huygens, Arnaud, and the philosopher Malebranche. He was also familiar with Newton, Boyle, and Spinoza. From December 1676 until the end of his life, Leibniz held various positions under the dukes of Hanover, traveling extensively throughout Germany. His major philosophical works include "Discourse on Metaphysics" (1686), "New System of Nature" (1695), "Theodicy" (1710), and "Monadology" (1714).

The construction of his philosophical system by G. W. Leibniz begins with an attempt to synthesize the achievements of ancient, medieval, and modern philosophy, intertwining mechanics and physics with metaphysics. To address questions regarding the fundamental nature of being (substance, or substantial form) and the ultimate purpose of the universe's development, Leibniz employs categories such as "entelechy" and "monad," albeit with a profound reinterpretation.

For Leibniz, the substance is represented by the monad. Monads are the "elements of all things" in the world, and their number is countless. These immaterial, non-extended entities are "metaphysical points," or units of the infinite universe of being, manifesting as centers of action, energy, and force. "In bodily substance," Leibniz writes, "there must reside the first entelechy... the original driving force, which in conjunction with extension always acts... This is the substantial principle, which in living beings is called the soul, and in others—substantial form... that which I call a monad."

All things of the natural world consist of monads as their ideal essences. Monads, being simple substances, lack parts; they are created by God and are eternal. They do not come into existence nor can they be destroyed through natural means. From the combination of simple substances arise complex entities—things, bodies, plants, animals, humans—that take shape through natural processes, acquiring material (bodily) characteristics of extension and multiplicity.

Each monad is unique; in each is ideally represented the entire universe, and each perceives, in its own way, all that transpires in the world, serving as a "living mirror of the Universe." The organic unity of the cosmos and the coherence among the elements of the universe are possible due to the principle of pre-established harmony, according to which God, from the very beginning, creates monads in correspondence with one another. Thus, the individual essences of monads do not dissonate in their interactions but harmoniously complement one another.

Leibniz asserts that all monads share the same nature but differ in degrees of perfection. Accordingly, the philosopher constructs a hierarchy of monads—simple substances—dividing them into three main tiers: 1) the so-called "naked" monads, which constitute the bodies of inorganic nature; 2) souls; and 3) spirits.

The monad of monads, or the highest original monad, is God. He is the creator and source of being for all other monads, which "arise from the continuous emanations of the divine." The lower level comprises the so-called "naked" monads, whose force is passive and manifests merely as mass, impenetrability, and extension. The soul-monads are more perfect, from which animals endowed with memory and the capacity for sensation are formed, yet they lack reason. The most perfect of monads are the spirits, which possess consciousness and the ability to reason.

Based on the principle of continuity, Leibniz overcomes the metaphysical dichotomy between spirit and matter, the living and the non-living; in his view, all nature emerges as a continuous chain of development, revealing itself as, to some degree, living and animated.

Leibniz articulates the principle of sufficient reason: "nothing occurs without a sufficient reason," through which the thinker proves the existence of God as the ultimate cause of things and justifies the assertion that the created world is the best of all possible worlds. This last thesis became widely known as the "theory of optimism." In the treatise "Theodicy," responsibility for moral evil is attributed to humanity, which sins and "fails to fulfill its purpose," while physical evil may arise as "a fitting punishment for guilt, as well as a means to an end, namely, to prevent greater evils and to achieve the greatest goods." Punishment serves equally as a warning and as a deterrent, and often evil leads to a greater appreciation of good and can even result in a higher perfection for the one who commits it. Thus, the existence of phenomena of imperfection and evil are necessary conditions and components of universal harmony.