The Boundaries of the Universe[*]

    Now that we know that the universe is real, we can ask what the universe implies.

There Is At Least One First Cause

    In nature, every effect has a cause that preceded it. A tree falls because it was chopped down. You are hungry because your body needs energy. The crops die because of the drought. With very little work, we see a problem. A tree falls down because it was chopped down. It was chopped down because a man was cold. A man was cold because it was winter. It was winter because of the position of the sun and the earth. The sun and the earth were where they were because they have been moving like a clock since they came into existence. They came into existence because of the laws of physics and the initial conditions of the universe. Hmm. What is the cause of the laws of physics and the initial conditions of the universe? Every causal chain eventually gets back to the question of what caused the universe. There may be more than one first cause (also referred to as an uncaused cause), but there must be at least one.

Objection 1:

    The universe has existed for eternity. It has no first cause because it never began.


    Current science has determined that this is not the case. First, there is very good evidence that the universe is around 13.7 billion years old and has evolved since its creation according to Big Bang Theory. Second, there is a law of physics called the second law of thermodynamics, or the law of entropy. What it says is that the amount of disorder in the universe is always increasing and can never decrease. If the universe is infinitely old and disorder always increases, then the present universe would have zero order and be unable to support life. If the law of entropy breaks, many other laws, such as conservation of energy and the direction of time also break. Therefore, the entropy "clock" must have started at some point in the distant past, when the laws of physics were created. This is the beginning of the universe.

Objection 2:

    There is an endless cycle of universe creation. Our universe was caused by another universe.


    This is possible. However, it does not avoid the problem. How did the first universe begin? Alternatively, perhaps there is an eternal series of universes. Then this eternal series of universes is the uncaused cause that caused our universe. There is no way of getting around the problem.

There Is At Least One Change Inducer

    Everything in the universe is in motion. In order for anything to change, something else must change as well. For a car to move, a person must fuel it and drive it. For a tree to grow there must be energy from the sun and rain falling from the clouds on a regular basis. For a star to be born, gravity must actively pull large quantities of space dust together. Again, if we push this train of thought, we quickly get to the boundaries of our understanding. Every change requires another change. A tree grows because sunlight falls on it. Sunlight falls on it because of the continuous nuclear reactions in the sun. There are nuclear reactions in the sun because atoms are being slammed together under the laws of physics. What gives the laws of physics the power to change nature? Every change depends upon another. Every change eventually depends upon a change inducer, or something that can change without being changed. There could be more than one change inducer, but there must be at least one.

There Is At Least One Existence Source

    Everything in the universe depends on something else for its state of being. A person requires air to breathe. A plant requires sunlight to photosynthesize. A bed requires a floor to remain level and stationary. Nothing in our experience can depend upon itself for all that it needs to remain in its current state. Again, we run into a problem when we push this line of reasoning. You require air to breathe. The air requires gravity to be held near a planet. Gravity requires the reliability of the laws of physics. What do the laws of physics require? Soon, if we follow this type of chain, we must get to something that can sustain itself as well as sustaining something else. This is a source of existence. There may be more than one, but there is at least one.

Now that we better understand the boundaries of the universe, we come to realize that at least some type of God must exist.


[*] The arguments in this section borrow heavily from the five ways of St. Thomas Aquinas (Summa Theologica, I.2.3), who in turn borrowed from Aristotle (Physics VIII, 4-6 and Metaphysics XII, 1-6).