Idealists and Materialists of Modernity

The Fates of Descartes' Project in the Works of Leibniz, Locke, and Many Other Philosophers

The term "spirit" in European languages always denotes a superior intellectual principle that transcends things and understanding, yet permits reasoning and rational operations. In Russian, however, "spirit" is more closely associated with experience; we cannot say "sharp spirit" in the sense of "wit," or "spiritualized by thought," whereas in European languages, such phrases are entirely normal. In German, as in other European languages, "spirit" signifies "mind," "contemplation," as well as a "general intellectual situation," as seen in expressions like "the spirit of the age" or "to act in such a spirit." Thus, idealism becomes, to some extent, a philosophy of contemplation understood as action, while materialism is viewed as a philosophy of action interpreted as contemplation.

Thomas Hobbes (1588—1679) emerged as the first Cartesian atheist. He reasoned that if extension is a property of all bodies, and bodies can take myriad forms, then extension encompasses all possible varieties of bodies, their shapes, and behaviors. Consequently, space is not some place with intrinsic significance but merely a "phantasm," an illusory representation that we substitute for the truth of things, becoming complacent and ceasing to investigate reality. In the same vein, God becomes an illusion, invoked to explain various movements: observing that something has changed position, that something is alive, or that something is lively and energetic, we again lazily conceive of an omnipresent, acting God. Hobbes proposed replacing all old conceptions with mathematics and physics: mathematics would connect logic with observations of the mechanisms of the surrounding world, while physics would demonstrate the unity of our experiences, including emotional experiences, with the material premises of the behavior of things. Moreover, Hobbes wrote about politics: in his famous treatise "Leviathan," he argued that the state is an illusion that has transcended itself. In a bid to end conflicts and egoism, the war of all against all, individuals acknowledge the authority of a monarch, submitting to all his commands, yet unbeknownst to him, the monarch serves as a point of social consensus; indeed, individuals are unaware of this, but the social contract becomes a reality. Thus, one illusion—the illusion of the monarch as savior—is surmounted by another, as if everything occurred by itself, and politics arose from private endeavors, even though it is in fact merely a collective social contract that has come into play.

John Locke (1632—1704) challenged one of Descartes' assertions regarding the soul's constant activity; this questioning was sufficient to forge his own system. Locke asserted that perceiving an object does not require thought but rather the initial amalgamation of simply experienced ideas. For example, we see a red ball. We must perceive the spherical shape, the red color, and that this ball is made of leather rather than wood. We commence thinking only when we bring forth arguments based on the situation, such as reasoning that a wooden ball would be harder to kick, while this particular ball is indeed kicked. However, we must first perceive the situation before we can comprehend it. Therefore, we think only at times, while at other times, we simply experience things.

Next, Locke addresses whether all knowledge is derived from experience, responding affirmatively. He states that there seem to be things we cannot know from any experience, such as the law of identity: no matter how many identical things we observe, we will never notice their identity unless we possess a prior understanding of identity. Yet, Locke counters that identity was once discovered by our reason, indicating that it was not originally present in the mind. The precise manner in which it was unveiled—whether through the mind noting its constancy or the constancy and permanence of certain phenomena outside the mind—is less important than the fact that this idea was initially absent. Locke characterized the initial state of the mind with the phrase "blank slate" (tabula rasa).

Although Locke's "sensualism," his doctrine that sensory impressions always precede intellectual operations, may appear naive from a contemporary philosophical standpoint, his great discovery was recognizing reason not merely as a capability of the intellect to differentiate things and concepts, as earlier thinkers believed, but as an independent principle within humans, allowing the formulation of the data of our experiences. In other words, it enabled us to view our experiences from an external perspective, thus opening the possibility for our consciousness to exist as a consciousness of experience—consciousness directed toward something, rather than a mere instantaneous awareness of self, as in Descartes. Therefore, without Locke, neither Hume nor Kant would have emerged.

Furthermore, in "Two Treatises of Government," Locke introduced the separation of powers into legislative, executive, and judicial branches for the first time, reasoning as follows: the state must punish those who disrupt order to maintain stability; however, this requires establishing a measure of punishment so that everyone knows what actions will incur penalties, thereby deterring future crimes. This gives rise to legislative power. Nevertheless, people still violate laws, believing they can breach order undetected, such as assuming a theft will not be discovered immediately or at all. This necessitates the executive power, which demonstrates that any breach of the system triggers a response: people, for instance, observe the integrity of locks, thus beginning to uncover thefts regardless of whether the owner has noticed the burglary. The most intriguing aspect arises next: it is essential that those observing the locks do not engage in theft themselves. Here, judicial power comes into play, which can initiate legal proceedings at any complaint. Locke envisioned the judicial power as akin to an army, seizing cities and invading homes, ensuring that judges and police do not themselves become thieves.

Locke stands at the origins of the Scottish Enlightenment, where the primary concepts become "reason" and "feeling." Reason no longer merely discerns the essence of things; it directs itself toward them and must remain "sane." Meanwhile, feeling transcends merely transmitting the individual properties of objects to our minds; it enables us to penetrate into things and situations, understanding not only how things appear or are structured, but also how they may interact, how they can resemble one another, and the possible kinship of things.

The next great figure of the Scottish Enlightenment was David Hume (1711—1776), who, as Kant acknowledged, awakened him from his "dogmatic slumber," from the notion that the reality of the world and thought could be described using ready-made philosophical categories, framing the issues of the relations between these categories as philosophical problems. It became clear that the very ability of our reason to create categories needed scrutiny; under what conditions is the creation of ideas by reason, which may be ascribed to things as valid, even possible? Hume reasoned as follows: any experience we have becomes a subject of heightened attention from reason— for instance, we remember a burn from fire more vividly than any of our reflections about fire, memories of it, or imagined representations of fire. Even if we learn many things not from our experience but from others', it is because we are transmitted not the things themselves, but their ideas, defined reflections of experience in consciousness. However, since our reason finds it more convenient to deal with a small number of simple ideas, it begins to condense experiential ideas into abstract notions such as the idea of good, beauty, or utility, which are then communicated to others. Evil arises when a person confuses simple and complex ideas, for instance, equating good with wealth, whereas clarity of reason enables a person to act flawlessly. In Hume's system, one cannot assert whether God exists or not, nor whether it is meaningful to speak of substances: whether we perceive fire as a distinct entity, as the oxidation of matter or its luminosity—this depends on our habits and the beliefs engendered by those habits, rather than on the intrinsic nature of what we call fire.

For Descartes, in contrast to his idealistic successors and subsequent sensualists and skeptics, the roughness of things, such as an apple only approximately resembling a sphere, does not discredit reality but rather presents us with significant tasks, testing us. We must learn, having accustomed ourselves to pure thought, to also elevate the complexity of things to the level of clear and distinct ideas. This demand for Descartes is directly tied to how he perceives his own body, one might say, to the phenomenology of his body. Descartes observes that he feels not merely a connection with his body but a profound bond, to the point of merging, achieving an indivisible unity. In this way, he resolves the task of transforming his unruly body, which suddenly seems too closely linked to him, into a clear idea.

Here I find myself in hunger, and I do not merely state, "my body is hungry" or "my body requires sustenance for further actions," but rather I declare, "I am hungry." For Descartes, this is not merely a close connection between mental and bodily experiences, but rather the ability of the spirit to engage with bodily experiences as independently valuable, irrespective of other experiences: we first rush to satisfy hunger, and only afterward do we contemplate other matters. Even if we renounce food for the sake of a thought—say, considering that it is better to first feed the hungriest among us—it still signifies that I have recognized my bodily experience as my own; I do not calculate how much pleasure the hungry neighbor might derive when I feed him, but rather I take delight in feeding him. Just as our mind knows which thought will be wittier for all, it similarly comprehends which food will be more nourishing for all.

Essentially, Descartes distinguishes between the functional order of the soul and body and the order of consciousness itself. In the functional order, the soul attends to the body, while the body sustains the soul; a healthy body houses a healthy spirit. This order is reduced to discrete episodes. In contrast, within the order of consciousness, the soul perceives the truth of such care, understanding that this concern will indeed be beneficial, which enables one to care for others, not merely oneself. This order ultimately emerges as a command and a norm.

Yet a final metaphysical question remains: when do I think? What powerful cause or impulse compels me to think? Descartes responds to this by turning to the concept of consciousness. When I contemplate what I am thinking, or, in other words, when I reflect on the very fact of my thinking, I come to grasp how precious and significant thinking is to me. Here, Descartes unveils the problem of value, a matter of great importance, for instance, to the Neo-Kantianism of the twentieth century and the cultural science it engendered. My thinking, when it thinks of thought, becomes so clear that I cannot help but notice this clarity. For when I think of an object, I may not fully understand what that object is; yet when I think of thought, I am aware that I confront only thought and nothing else.

However, we desire to think not only of thought but of various other things as well. For example, we may choose to contemplate the sun or the sunflower, which was introduced from Peru in the seventeenth century. We think of these things quite clearly, although not as clearly as we do of thought. For instance, we can calculate the size of the sun or count the number of petals on a sunflower. Furthermore, for greater clarity, we might determine the mass of the sun and the average number of petals in sunflowers within a given area. From there, we would proceed to types of stars and the beneficial properties of sunflower oil, continually striving toward clarity. Essentially, Descartes explores "energy," the activity of things, while clarity corresponds to what Aristotle termed completion, or "entelechy."

Yet even more intriguing than knowing the things of our world is the pursuit of knowledge about God. For Descartes, God's existence is not about His hypostases (persons), as in Christian theology, but rather His perfection, though one could derive the Trinity and other Christian dogmas from the will of God. The sun possesses the shortcoming in comparison to God of existing not by its own essence but solely by the will of God, thus limiting its interest to whatever will has been granted to it by God. Again, Descartes distinguishes between formal infinity as the pure cause of the idea of the infinite and material infinity, namely, the idea of the infinite as the sole objective content of all my ideas. For instance, the content of the idea of a sunflower would be that it stretches infinitely toward the sun if it were to exist indefinitely, or that it infinitely varies its appearance, all its veins.

Thus, for Descartes, there is "essence," which emerges as "objective reality," that is, the aspect of a thing that our mind can perceive, and there is "existence," which in turn represents "formal reality," shaping our thought. For example, the essence of a sunflower manifests in its being a flower, which consequently bears fruit, while existence is embodied in our ability to admire it or in its blossoming among other flowers. It is noteworthy that Descartes simplifies Aristotle's framework, foundational to prior thought. Aristotle taught that a thing's essence, its "authenticity," its "true nature," literally "the thing as it was," is its being—its essence as a flower. A flower is a flower not because it grew from a seed and will bear fruit, but because it can be a flower and not a beast or a bird. Conversely, existence is the capacity to act in conjunction with some cause: for example, a flower may please us, but not because it itself is the cause, but rather because sight is the cause, and the cause of sight is the very arrangement of the world. According to Aristotle, to exist is to be something, not merely to be.

To elucidate how essence and existence relate over time, Aristotle, followed by all philosophy up until Descartes, distinguishes material, formal, efficient, and final causes, demonstrating how a thing, while singular, can simultaneously partake in the composition of the world and its events. For Descartes, the event itself is existence, the very act of being in time, while essence is the initial being that can be conceived beyond time. In other words, the opposition between essence and existence reduces to the age-old contrast of the intelligible and the sensible, where the intelligible is deemed "objective" and imperative, whereas the sensible is viewed as "subjective" and driven by interest—a growing interest in the properties of things. This new schema persists in philosophy to this day, although the status of both the objective and the sensible has been repeatedly reassessed.

Efforts to unify the status of the objective and the status of the sensible within a singular concept are more than significant for new philosophy. In 1696, Gottfried Wilhelm von Leibniz (1646—1716) introduced the term "monad." His reasoning was thus: if a thing consists of parts with their properties, it can be deconstructed into separate components, whose properties, in ultimate reduction, amount solely to being these components. Unlike Aristotle's followers, for whom a substance could be anything that serves as a subject in a phrase, for Leibniz, a substance must withstand a test of truth and falsehood. For example, a ship may be broken down into timber, a person may die, a tree may grow from a seed—can these instances of existence be considered substance, if they sometimes are and sometimes are not? Yet the soul, number, and being remain unchanged, and one can envision monads as units of meaningful existence from which all things are composed.

Moreover, Leibniz, following the Jesuit Athanasius Kircher (1608—1680) and his teacher Erhard Weigel, contemplated a universal logical language that would replace natural languages, deemed too arbitrary, with their myriad exceptions, ambiguities, and excesses. The question of a universal language, akin to the universal mathematics or logic for all humanity, was not posed in antiquity because language was primarily seen as a physiological capacity, and logic and rhetoric applied equally to words and things. Yet in the Middle Ages, the question arose of language as a unique creation, which differs from other creations in that it may more swiftly lead one to God. This was based on the "tree of Porphyry," a schema invented by the ancient systematizer of philosophy to teach the avoidance of confusion between genera and species, clarifying the hierarchy of concepts from the most general to the most particular. The missionary Raymond Lull (1235—1315), who lived in Mallorca, devised a logical machine that provided a means of combining any abstract concepts to produce only true propositions. Athanasius Kircher, a connoisseur of ancient Egypt and China, was inspired by the image of hieroglyphs, which could signify both a distinct concept and an entire phrase, thus offering a more comprehensive and vivid representation of Christian truths. He sought to create a universal language by unveiling the logical structure of concepts and presenting them in the form of simple schemes, even merely arithmetic combinations, intended to convey the full diversity of objects and judgments. Leibniz refined Kircher's endeavor, demonstrating that concepts must not only be differentiated but also systematically compared, requiring that their relationships be represented not merely as a branching tree but as a table of calculations, examining under which combinations concepts yield a tangible effect—in other words, facilitating an increase in knowledge.

Leibniz posits a significant doctrine of "minor perceptions," or, in other words, the perception of things that escape our notice. We perceive the sun or a tiger, a major perception that we cannot simply overlook. Yet, we remain oblivious to the air we breathe. We acknowledge substantial historical events while often ignoring the minutiae. For "minor perceptions" to integrate into our consciousness, "apperception" is required—this is a conscious relationship to the very act of our perception. We must inquire about what precisely we are perceiving at this moment and what we are capable of perceiving here and now. Apperception encompasses both attention and memory, allowing us to recall those perceptions we had not previously recognized, those that remained unconscious. The essence of this doctrine is that consciousness serves not only as the center of decision-making but also as the hub for organizing past decisions that have already been realized; it enables us to discern not only what we can do now but also what has transpired with us. The teachings on perception and apperception are intricately linked to Leibniz's "optimism," his belief that, however flawed our actual world may be, it is still superior to all possible worlds; for even if we envision these worlds in their entirety and imbue them with superior qualities, we cannot recall them, and thus cannot make the necessary decisions.

Christian Wolff (1679—1754), a disciple of Leibniz and teacher to Mikhail Vasilyevich Lomonosov, extended the principle of sufficient reason to encompass all things. Leibniz maintained that one could only pose the question of the foundation for the existence of a given thing in relation to "contingent" things—this term, of scholastic origin, signifies that something may be so but could just as well be otherwise. Wolff contended that any entity, even one whose existence is assured and incapable of becoming anything else, must also have a sufficient basis for its existence: after all, it exists within time, in this sense aging; it occupies space, thereby mastering that space; it may serve as a foundation or justification for other things, for instance, when we exchange one item for another. Leibniz, one of the founders of differential calculus, conceived of the relationship between things as a system of meaningful distinctions and usages, much like one would consider a budget. Wolff, primarily a physicist, envisioned differently, asserting that all things could correspond with one another, for instance, by mass or volume, and thus could be exchanged; in other words, he thinks not in terms of a budget's state but of the state of transactions. Therefore, for Wolff, the existence of an entity manifests, for example, in its capacity to become permanent in such a manner that this permanence demonstrates that only it could have been possible in that context.

Another significant achievement of Wolff is the novel distinction between "simple" and "complex" substances. For him, these are not merely two different types of substances but also two distinct modes of existence. A simple substance exists in such a manner that it requires no analysis; it appears as a factual given. Consequently, simple substances define, say, motion, for we can immediately ascertain where it originates and where it is directed. Conversely, a complex substance is presented as a subject for analysis, determined not only by its parts but also by its interconnectedness: whether it is linked in space or also in time, or in relation to other things. This interconnectedness serves as a tool, allowing us to compare one complex substance with others. Here, Wolff encounters certain difficulties, such as whether one can assert, regarding a complex substance like a human being, the immortality of the soul and the mortality of the body, if neither is derived from interconnectedness but solely from observations external to it. Wolff resolves this issue by positing that soul and body are designations of particular modes of existence of a complex substance, thus immortality and mortality are not defined as inherent properties of the parts but rather as primary properties of the complex substance itself, whereas "being a soul" and "being a body" become secondary properties. What enters the physical world becomes a body, and what enters the realm of thought and contemplation becomes an immortal soul. This position of Wolff would later be rigorously criticized by Kant, sometimes with reference and sometimes without, as it leads to the conclusion that necessity is dependent on contingency, on such a random occurrence, which appears absurd.

Johann Nikolaus Tetens (1736—1807), a contemporary of Kant, was a mind as universal as Leibniz and Wolff. His works spanned biology and zoology, and as the director of the Danish Royal Bank, he implemented one of the most notable monetary reforms in history. While Wolff examined the structure of complex substances, Tetens also explored the structure of complex concepts, perceiving them not merely as a means of grasping a situation in being but also as a method of relating the sensual and the intellectual in our philosophical endeavors. Tetens argues that people tend to think hastily, and the expression of this hastiness is imagination, or arbitrary generalization of a vast number of data. In contrast, a complex concept thwarts such imagination and, moreover, delineates how possibility and necessity diverge. For instance, the concept of "bird" encompasses both wings and a specific aerodynamic form—wings signify the possibility of flight, while the shared form among all birds indicates regularities within the avian world. Thus, our imaginations are curtailed, and we recognize the limits of our concepts, as they are constrained by possibilities and necessities. While Tetens may not be as radical as Kant in his "Critiques," he nonetheless demonstrates that boundaries apply not only to physical things but also to intellectual constructs.