What Caused the Beginning of the Universe?
-Christina Hillesheim, PhD
For much of history, many people believed the universe had always existed. The ancient Greeks viewed the cosmos as eternal, without a true beginning. Even many scientists in the early twentieth century assumed the universe was static and unchanging.
Then everything changed.
Scientists discovered that the universe is expanding. As they traced that expansion backward in time, they arrived at a startling conclusion: the universe appears to have a finite beginning.
This idea became known as the Big Bang theory. The Big Bang was not simply an explosion inside the universe. It was the beginning of the universe itself — including space, time, matter, and energy.
This discovery raised an unavoidable question:
If the universe began to exist, what caused it?
That question lies at the heart of one of the most famous philosophical arguments for the existence of God: the Kalam cosmological argument.
The Kalam Cosmological Argument
The Kalam cosmological argument is built on three simple ideas:
Whatever begins to exist has a cause.
The universe began to exist.
Therefore, the universe has a cause.
At first glance, the argument may seem almost too simple. Yet for centuries, philosophers, theologians, and now even scientists have debated these ideas because of what they imply about reality and existence.
The argument does not attempt to explain every detail about God or the origin of the universe. Instead, it asks a more foundational question: if the universe had a beginning, what could have caused it?
Modern science has made this question especially important. The discovery that the universe appears to have a beginning gave new attention to a debate that had once been largely philosophical. Today, discussions about the origin of the universe involve not only philosophers and theologians, but also cosmologists and physicists.
Did the Universe Really Begin to Exist?
For centuries, the idea that the universe had a beginning was heavily debated. Many ancient Greek philosophers believed the universe was eternal, and even many scientists once assumed that the cosmos had always existed in a steady, unchanging state.
However, modern cosmology dramatically changed that discussion.
In the 1920s, astronomer Edwin Hubble discovered that distant galaxies are moving away from us. The farther away a galaxy is, the faster it appears to be moving. This revealed that the universe is expanding.
If the universe is expanding today, then tracing that expansion backward suggests that the universe was once compressed into an extremely hot, dense state. According to the Big Bang model, space, time, matter, and energy all came into existence at a finite point in the past.
This does not mean scientists have discovered what caused the universe to begin. In fact, that remains one of the biggest unanswered questions in science. But today, the evidence that the universe had a beginning has become difficult to ignore.
The idea of a beginning also raises an important philosophical problem. If the universe began to exist, then it cannot explain its own origin. Something cannot create itself before it exists.
That leads to the next question: can anything come into existence without a cause?
Can Something Come From Nothing?
Imagine coming home one day and finding a horse standing in your kitchen.
You would not assume the horse simply appeared out of nowhere. You would immediately begin asking questions. How did it get there? Who brought it inside? Where did it come from?
In everyday life, we naturally assume that things have causes. We never see objects suddenly appear uncaused out of nothing.
The same principle applies to the universe itself.
Supporters of the Kalam cosmological argument argue that if the universe began to exist, then it must have a cause. After all, something cannot come from absolutely nothing. Real “nothing” is not empty space, darkness, or a vacuum. It is the complete absence of anything — no matter, no energy, no space, and no time.
Some scientists and philosophers have suggested that the universe could arise from “nothing” because of quantum physics. However, the “nothing” described in these theories is usually not truly nothing. It still involves physical laws, quantum fields, or mathematical structures that already exist.
The central question remains: why does anything exist at all instead of nothing? If the universe had a beginning, then many philosophers argue that it is far more reasonable to believe it had a cause than to believe it appeared without one.
What Kind of Cause Could Create a Universe?
If the universe had a beginning and requires a cause, then what would that cause have to be like?
According to the Kalam cosmological argument, the cause of the universe would need to exist beyond the universe itself. Since space, time, matter, and energy all began at the Big Bang, the cause could not be made of physical matter or be limited by space and time.
In other words, the cause would need to be timeless, spaceless, immaterial, and incredibly powerful.
Many philosophers have also argued that the cause must be personal. Scientific explanations normally describe how one physical state leads to another through natural laws. But if the universe was the beginning of all physical reality, then there were no earlier physical conditions or laws to explain it.
This leads some thinkers to conclude that the universe was caused not by an impersonal force, but by a mind capable of choosing to create.
While the Kalam cosmological argument does not explain everything about God, many people believe it points toward the existence of a Creator who exists beyond the universe itself.
Why This Question Still Matters
The question of where the universe came from is more than just a scientific puzzle. It is one of the deepest questions human beings can ask.
For centuries, people assumed science would eventually remove the need for belief in a Creator. Yet modern discoveries about the beginning of the universe have caused many scientists and philosophers to revisit questions once thought to belong only to religion and philosophy.
The Kalam cosmological argument does not prove every detail about God, nor does it answer every mystery about the universe. However, it does point toward an important conclusion: the universe may not be a meaningless accident that appeared without reason or cause.
If the universe truly had a beginning, then perhaps the existence of a Creator is not only possible, but reasonable to consider.
Suggested References
Craig, William Lane. The Kalām Cosmological Argument. Eugene, OR: Wipf and Stock, 1979.
Craig, William Lane. Reasonable Faith: Christian Truth and Apologetics. Wheaton, IL: Crossway, 2008.
Lennox, John. God’s Undertaker: Has Science Buried God? Oxford, England: Lion, 2009.
Meyer, Stephen C. Return of the God Hypothesis. New York: HarperOne, 2021.
Strobel, Lee. The Case for a Creator. Grand Rapids, MI: Zondervan, 2004.
Christina Hillesheim is a chemist and apologist based in Zagreb, Croatia, where she holds a Doctorate in Chemistry and a Master of Divinity in Apologetics. Having once believed that science and Christianity were in conflict, her investigation into the evidence led her to a different conclusion. Today, she speaks on questions related to science and faith through her collaborations with Women in Apologetics, Reasons to Believe, and Apologetics on Mission. She also creates apologetics content on her YouTube channel (https://www.youtube.com/@ChemistryFish23) and manages Postoji nada, an online platform that helps people explore questions about mental health, addiction, and faith. When she’s not working, she enjoys time with her dog, Guapo—a German Shepherd and Belgian Malinois mix.