The Best Philosopher of Possible Worlds

Gottfried Wilhelm Leibniz is one of the two individuals whom I say have "solved the problem of man," in his own words, living in the best of all possible worlds.

The foundation of his philosophy is the idea that because God is a perfect being, the world He created must be the best of all possible worlds—a notion criticized by Voltaire in his novel Candide. According to Leibniz, God chose the world we inhabit among all possible worlds because it achieves the greatest variety and harmony simultaneously, while realizing this diversity through the simplest possible laws. Something being possible in isolation does not mean it is possible in combination with other things. You may love someone; that is possible. They may love you back; that too is possible. But it may not be possible for both of them to be happy together. The existing universe is constructed according to the principle that the greatest number of possibilities must coexist without contradiction. Thus, it is the union of the maximum number of possibilities that do not conflict with one another.Leibniz's conception of this perfect universe is in fact a rebuttal to Newton's concept of time and the functioning of the universe.

After adopting the idea of a perfectly created universe, Leibniz devoted nearly all his work to proving it. This placed him in constant opposition to Newton. According to Newton's view, the universe required external intervention after a certain time. According to the law of gravity, stars and planets would gradually disrupt each other's motions and eventually collapse. Newton believed that God intervened periodically to correct this problem. To him, God was a being who intervened in the universe and thereby demonstrated His sovereignty. Leibniz objected to this by saying: "If God must constantly wind the clock He made, He is not a perfect clockmaker. To be God requires producing a flawless clock." For Leibniz, God created the universe according to a law or formula, and if we discover this formula, we can learn all events with mathematical certainty. This also means: "The future is already complete in God's mind." The fact that the future has not yet occurred for us does not mean it has not occurred for God. If we discover the universal formula used in the creation of the universe, we too will be able to see the future.

Let us expand on this. For Newton, time is an independent entity in itself, separate from everything else. Newton viewed time as an infinite empty container into which objects are placed. To him, time flows like a river regardless of whether objects are present or absent. For Leibniz, however, time is not an entity in itself but the ordering of events. If there were no events or changes in the universe, there would be no such thing as time. Time is the way our minds arrange events as "before" and "after." This definition of time is the first reason I say Leibniz solved the problem of man. In my view—as well as, if I interpret correctly, in Islamic doctrine—all things already exist in their completed form on the Preserved Tablet. We arrive at events that have already occurred, over time. Or rather, we perceive our arrival as time. Leaving aside my personal view, let us return to the subject. Years, even centuries later, Einstein proved that time varies according to the observer's speed and gravitational field, thereby validating Leibniz. If time were an independent container as Newton claimed, it would flow uniformly everywhere. But the fact that time changes with speed demonstrates that it is directly related to objects and motion—that is, as Leibniz said, a relationship between events. The theory of relativity also confirmed Leibniz's definition of time as "the ordering of events relative to one another." Because two events occurring simultaneously for one observer may occur at different times for another observer moving at a different speed. This shows that time depends on the observer's relationship with other objects. Moreover, Einstein, by unifying space and time in his theory, demonstrated the truth of Leibniz's claim that "if there were no events or changes, there would be no time." In summary, according to Newton's perspective, God created an absolute space and time void and placed matter within it. In this view, God can intervene at any moment and alter the rules. This is another way of saying miracles are possible. For Leibniz, however, God established the most perfect laws once and remains faithful to them. The universe is a reflection of God's intelligence. Constant intervention would be an insult to that intelligence.

Leibniz attempted to prove that God's continuous intervention in the universe was unnecessary on two distinct grounds:

1. Demonstrating through calculus that the universe operates continuously, without interruptions or jumps.
2. Introducing a new definition of force and showing that the universe conserves its own energy continuously.

The dispute over who first discovered calculus led Leibniz to such isolation that almost no one attended his funeral except his secretary. Newton was so powerful in the scientific community of the time that he accused Leibniz of stealing calculus from him, resulting in Leibniz's exclusion from the scientific establishment. Today, the accepted view is that both independently discovered calculus. Newton developed calculus to measure planetary motion, while Leibniz developed it to prove that there are no jumps in nature and that everything exists in continuous flow. Leibniz believed that by moving from infinitesimals to the whole and from the whole to the greatest, he could prove God's existence.

The debates over the nature of force, the second point, are also highly significant and fascinating. Newton argued that the fundamental quantity of motion in the universe is the product of mass and velocity, mv. Thus, force is the change in a body's mass multiplied by its velocity; when two bodies collide, what is conserved is their mv value. This assumption naturally leads to the conclusion that motion can be destroyed in collisions, implying that the universe experiences continuous energy loss and therefore requires external reinforcement, that is, from God. Leibniz, however, argued that true force is proportional to the square of velocity, that is, mv². He reached this conclusion through the following reasoning: Suppose we expend a certain amount of force to lift a body to a height of four meters. When the body is released and falls to the ground, its velocity, according to Galileo's laws of falling bodies, is not four times the velocity of a body falling from one meter, but only twice as great. If four times as much work was expended to lift the body to four meters, yet it gains only twice the velocity upon impact, then the true force within the body must depend not on velocity but on the square of velocity, because only by squaring two do we obtain the four units of energy expended. At this point, squaring velocity demonstrates that energy is not lost, eliminating the need for external intervention in the universe. For those who might say, "Okay, but what's the point? What difference does squaring make?" or those who think but cannot articulate: Newton's mv formula is a vector quantity, so when objects move in opposite directions and collide, force is lost. But Leibniz, by using the square of velocity, transforms the expression into a scalar quantity. Thus, Leibniz called this Vis Viva, or "Living Force." This force does not disappear; it changes form. When large bodies collide and their velocities drop to zero, the small particles within them continue their motion. From today's perspective, both are correct but defend different concepts. The quantity Newton defended is called momentum; the quantity Leibniz defended is called kinetic energy. In this sense, Leibniz laid the groundwork for the first law of thermodynamics, that is, the conservation of energy, and even for Einstein's E=mc² formula (though many scientific developments occurred in between).

Leibniz was not only criticized in physics and mathematics but also in philosophical and religious matters, and he himself criticized some philosophers. One of the most important of these debates was his dispute with John Locke over the nature of knowledge. In this debate, which seeks to answer the question "What is the source of knowledge?", Locke, in his work An Essay Concerning Human Understanding, argued that the human mind is a blank slate at birth, or tabula rasa. According to him, no ideas are innate; everything is inscribed on this blank slate through experience and sensation. Leibniz responded to this work with his own book, New Essays on Human Understanding. To Locke's claim that "nothing is in the mind that has not passed through the senses," Leibniz added the phrase "except the mind itself." For Leibniz, the mind is not a blank slate waiting to be written upon, but rather, in his own words, a veined block of marble. The natural veins within the marble—the principles of logic, mathematical truths, and the idea of God—are already inscribed into the marble at birth. A sculptor striking the marble does not create something new but reveals the veins, that is, the potential knowledge, already present within. Modern medicine today confirms Leibniz's view on this matter by asserting that infants are born with certain innate abilities, such as language acquisition capacity and facial recognition.

We have praised him extensively, but history has, at least for now, shown him to be wrong on some points. For example, Leibniz argued that there is no void in the universe. But according to current knowledge, about ninety percent of matter consists of empty space. He claimed that everything in the universe is determinable in a calculable manner, yet Heisenberg's Uncertainty Principle contradicts this. Nevertheless, I still believe Leibniz was right on this point. At a creator-level perspective, when we elevate coordinates to an extremely precise level and can observe everything in its entirety, uncertainty may vanish. The most significant error Leibniz made was believing that the universe is a system that continuously renews itself and progresses toward perfection, because thermodynamics states that the total disorder, or entropy, in the universe is constantly increasing.

The debate with Locke over the blank slate and innate knowledge was ultimately resolved in the last century by the answer given to the scientific community's question known as the Molyneux Problem. The question was: "Imagine an adult who was born blind and learned to distinguish a sphere from a cube made of the same metal by touch. If this person's eyes are suddenly opened, can he, without touching the objects, identify which is the sphere and which is the cube merely by sight?" Locke answered "no," while Leibniz answered "yes." Recent research conducted in India on children born with congenital cataracts who gained sight after surgery has confirmed Locke's view. When their eyes first open, children can see objects but cannot distinguish a cube from a sphere merely by sight. However, after a short time, they learn to do so. Still, I believe Leibniz was right in this matter. I think a mind of Leibniz's caliber would recognize the difference immediately upon seeing.

Before addressing the second reason I said Leibniz "solved the problem of man"—the problem of evil—let me briefly mention his invention of the binary system, which made it possible for me to write these lines on a screen and for you to read them. It is well known that holy scriptures describe God creating the universe from nothing. For Leibniz, the binary system was proof that God created the universe from nothing (0) using only one (1), because everything can be represented and expressed using only 1 and 0. He believed that everything could be represented using the binary system instead of the decimal system we use today. Although computers did not exist in his time, Leibniz invented the first mechanical calculator capable of performing the four basic operations, inspired by the same idea: that everything can be reduced to simple forms and mechanized. He conducted all these scientific works while serving as a political advisor and lawyer, producing ideas and studies on diverse subjects ranging from mining operations to European political unity.

Now let us turn to the problem of evil. According to Leibniz, God is infinitely wise, good, and capable of doing everything. Before creating the universe, God had an infinite number of possible world scenarios in His mind. God chose the world in which the greatest good is achieved with the least evil. That is, He selected the optimal among all possible worlds. The term "best" here does not mean a world entirely free of evil. It means the world in which the highest degree of harmony is achieved as a whole. According to Leibniz, there are three types of evil. The first is the deficiency inherent in created existence. Evil is the absence of good, and the only being without deficiency is God. The second is physical evil: illness, pain, and natural disasters fall into this category. Leibniz views these as warnings or tests that serve a greater good or promote moral maturity. The third is moral evil, committed by human free will. God does not will this evil directly, but He permits it because allowing humans to be free beings is a greater good than preventing evil.

When we see evil in the world and ask, "How can evil exist if God exists?", it is like looking only at a house's toilet and saying, "What kind of house is this?" We must not judge the entire universe based on a small part of it. Finally, let us answer a question that may occur to some: If the universe, as Leibniz claims, conserves its energy and does not decay, how can the Day of Judgment occur, and how can the afterlife begin? Leibniz has an answer to this as well. According to Leibniz, the afterlife is a higher version of the current world. When the time God has set for this world expires, a higher level will come into effect. As I stated at the beginning, continuity is fundamental for Leibniz. God created the monads—the indivisible, non-material, spiritual or mental units of the universe—from nothing, but He does not destroy what He has created. The concept of monads is an entirely separate topic; if I delve into it here, this text would double in length. In summary, just as a caterpillar transforms into a butterfly, our current world or universe will eventually transition from a material realm to a spiritual one. In the new version, physical form will disappear, leaving only energy.

Final note: Leibniz's works, Monadology and Theodicy, as well as Aliye Çınar's article "The Problem of Evil and Theodicy in Leibniz," are not overly long (50–70 pages) and should certainly be read by anyone interested in the subject. Many of the analogies used in this text are taken directly from Leibniz's original writings. The central ideas regarding Theodicy were also drawn from Aliye Çınar's article.