Atheists object to theists who say, “God does not need a cause and is therefore eternal,” by responding, “Then the universe also does not need a cause.” But can the universe really be a collection of beings with no beginning?
It can be said that one of the most important debates in the history of thought is the existence of God and, accordingly, whether the universe is finite or infinite. We see that materialist philosophers (the most influential being Karl Marx and Friedrich Engels) reduce the most fundamental philosophical problem to two propositions:
- Either matter and nature are prior, that is, eternal, and therefore God does not exist.
- Or God is prior, that is, eternal, and therefore matter and nature are the work of God.
Materialist philosophers and scientists defend the first proposition, accepting matter, time, and the universe as eternal, and thus argue that there is no need for God. Theists, on the other hand, maintain that God is eternal and that the universe was later created by God. There is also a third view, represented by thinkers such as Plato and Aristotle, which holds that both God and the universe are eternal. In this debate, then, the central issue is whether matter and the universe are eternal or not.
Two major arguments can be put forward to support the claim that the universe has a beginning and is therefore not eternal.
The first is the cosmological argument. According to the most widely accepted cosmological theory today, the Big Bang, the universe has a beginning in time, approximately 13.8 billion years ago. The idea of an “eternal universe coming from infinity” has largely lost acceptance after the Big Bang theory, although alternative theories still exist. Nevertheless, the Big Bang remains the most widely accepted model. Working on Einstein’s equations, Georges Lemaître theoretically demonstrated that the universe is expanding. Edwin Hubble later confirmed this theoretical discovery by observing that stars and galaxies are moving away from one another. Thus, the universe was not static, fixed, and eternal as Newtonian physics had suggested.
When the expansion of space is traced backward toward the beginning of time, it leads to the disappearance of space itself. According to the equations of relativity, time, which is bound to space, must therefore have been created simultaneously with space and matter. After Einstein’s formulas undermined the notion of absolute time, time also lost its supposed property of having existed eternally. Time came to be understood as a relative concept with a beginning. However, this does not mean, as some assume, that time is merely a concept produced by the human mind and has no existence in the external world. On the contrary, because this approach connects space, time, and matter and explains them mathematically, it attributes reality to time in the external world just as it does to matter.
According to the expanding universe model, expansion counterbalances gravitational attraction, preventing all matter in the universe from collapsing into a single object or mass. A universe that is expanding is larger at every moment than it was at the previous one. This also means that every earlier moment of the universe was smaller than the present one. This implies that, in the distant past, the universe began from a single component. Lemaître identified this as the starting point of the universe. This moment is what is called the Big Bang. Before this, neither the universe nor matter existed. In other words, this is the moment when the universe began from a single point.
Calculations showed that this “single point,” containing all the matter of the universe, must have had “zero volume” and “infinite density.” The universe emerged through the expansion of this zero-volume point. In fact, “zero volume” is a theoretical expression. Science can describe the concept of “nothingness,” which lies beyond the limits of human comprehension, only by using the expression “a point of zero volume.” In reality, a “point of zero volume” means “nothingness.” According to the conclusions of this theory, it is clear that the universe came into existence out of nothing. In other words, it was created.
The second argument is based on the laws of thermodynamics, which indicate that the universe must have a beginning. In a closed system, entropy (disorder) continually increases. Objects with higher temperatures gradually transfer their heat to their surroundings until they reach thermal equilibrium. This is something we observe in nature and everyday life, such as when a hot pot or a hot drink cools down. If the universe had existed eternally, then it should already have reached thermodynamic equilibrium. In that case, heat would be evenly distributed throughout the universe. But is this what we observe today? No. In the present universe, there are extremely cold regions and celestial bodies as well as extremely hot ones. According to the laws of thermodynamics, the universe is moving toward such thermal equilibrium in the future, where temperatures everywhere will tend to become equal. This means that the universe cannot have existed eternally. Thus, like the Big Bang theory, the laws of thermodynamics also lead to the conclusion that “the universe has a beginning and came into existence later.”
Gottfried Wilhelm Leibniz, who asked the question “Why is there something rather than nothing?”, stated that it is impossible for the universe to contain the explanation of its own existence and that it requires an explanation external to itself. If the universe has a beginning, then there must be a will and a power that desired and chose its existence, because its existence and non-existence are equally possible. Therefore, there must be an agent who preferred existence over non-existence and who also possesses the power and knowledge to bring this about.
When we add the question “Why are there scientific laws rather than chaos in the universe?” to Leibniz’s question, the need for God becomes even clearer. The fact that scientific laws operate in the same way everywhere in the universe and across different periods of time requires an explanation. Science does not undertake to provide such an explanation. Science is concerned with discovering laws, not with why those laws exist. Yet the very possibility of doing science depends on the existence of these laws. If the universe were chaotic, we could not speak of gravity, thermodynamics, or the laws of biology and physics. In short, science itself would not exist. Our understanding of the universe depends on causality, that is, scientific laws, and causality is the foundation of reason. A human being unable to establish cause-and-effect relationships would be more confused than a newborn baby. Even a baby’s mind possesses an innate category of causality. For example, if objects around us were to suddenly appear and disappear without any cause, how could our minds make sense of this? We are able to recognize plants, fruits, and vegetables and nourish ourselves because they consistently maintain the same characteristics.
This can be explained with another metaphor: if all the coins found in an archaeological excavation bear the same symbol, we look for a common cause and source. If all the documents in an archive are written in the same handwriting, we explain the archive by reference to a single author. Likewise, the laws that operate in the same way throughout the universe must also have an explanation. The existence of God provides such an explanation by accounting for the existence of these scientific laws and for why they are constant.