Can Monotheism Be Proven?

Monotheism, or the belief in a single god, cannot be proven, inasmuch as any theory in philosophy, religion, or science is impossible to prove. However, there are significant arguments for monotheism that point to it being a logical belief.

Contributing Writer
Published Feb 19, 2020
Can Monotheism Be Proven?

“Yeah, but you can’t prove there’s a god.”

“How do you know there’s only one? Why do you think your God is so special?”

Arguments and questions like this are common. How is a Christian to respond?

These are objections to the belief system of monotheism. Monotheism is the belief that there is only one god. The primary monotheistic religions are Islam, Judaism, and Christianity, which all hold to a belief in a single creator God.

However, many ideologies embrace polytheism (many gods), pantheism (everything is god), or atheism (no god). Especially in modern Western culture, it is common to accept all beliefs as equally valid.

This brings up the question: is there actually only one God? And can that be proven?

Can Anything Be Proven?

The first rule to remember when discussing belief systems is that no theory can be proven; it can only be the most current, logical, and available conclusion. Even generally unquestioned scientific theories, like gravity, are technically not proven, as not every situation and angle that has ever existed can actually be tested.

So, the simple answer is no, you can’t prove that there is a God, nor can you prove that there is only one. However, there are significant reasons to believe that this is the most logical conclusion with the information and evidence we have been given.

Though there are many arguments for the existence of a higher power in general, which can be helpful to get to the point of arguing how many exist and the nature of these powers, the arguments below have been selected specifically as those pointing most strongly to monotheism, though some of them assume that there is indeed some sort of higher power in order to make the argument.

With this said, below are five common arguments for the existence of a monotheistic God.

1. The Moral Argument

“Morality is relative,” you may have heard someone say. But you would be hard-pressed to find a person who actually lives out this mantra.

If morality is truly subjective, there can be no argument against any and all behavior. Genocide is acceptable. Rape is acceptable. Torturing children is acceptable. If there is no moral standard, then anything at all is acceptable.

However, humanity is largely incapable of thinking this way. Within all societies, since the dawn of history, there have been common threads of what is morally right or wrong. These aren’t always the same, but the general principles are there. Children should be cared for. Families should be protected. Adultery (whether against one spouse or many) is wrong.

Some might say that moral standards, then, are created by society or evolution. This, however, leads to the terrifying conclusion that if the majority decides something, for example, genocide, is right (think Nazi Germany), then it is, in fact, now morally right.

This leads to the reasonable conclusion that there is thus some sort of transcendent moral standard somewhere out there.

For the sake of brevity of this article, we can’t address all the objections to this idea, but if the idea of a transcendent moral standard is accepted, then someone or something must have created this moral standard. The moral argument, then, goes something like this:

  • If there is a transcendent, objective moral standard, there must be a transcendent, metaphysically sufficient creator of that standard; There is a transcendent, objective moral standard (according to our above discussion).
  • Therefore, there is a transcendent, metaphysically sufficient creator of the objective moral standard.

Thus, this argument points to the very existence of morality, whether exercised by Christians or not, as evidence of the existence of God.

But why a monotheistic God? Quite simply, if there is one objective, transcendent moral standard, then it can only have been created by a completely transcendent being, and thus, if there were multiple transcendent beings, there would not be one completely transcendent being, and thus there could not be one moral standard but, rather, moral dissonance.

Of course, there can be objections to this argument, but it is one of many that together lend to the logical stability of monotheism.

2. The Cosmological Argument

This argument reasons from the existence of the universe. The argument goes like this:

  • The universe exists; It is possible for things not to exist; Whatever has the possibility of non-existence, yet exists, has been caused to exist.
  • Thus, the universe had a cause; The universe could not bring itself into existence since it must exist to bring itself into existence, which is illogical; There cannot be an infinite number of causes to bring something into existence, because an infinite regression, going on forever, has no initial cause at all.
  • Therefore, there must be an uncaused cause of all things; The uncaused cause must be God.

This argument, granted, has its flaws; what caused God? As Christians, we respond that God, being God, was never caused, but has always existed. 

But how does this point to one God? It doesn’t, directly. However, one God is more logical for the simple reason that one original Cause is a less complicated answer than multiple causes, for which there also must be causes. Going all the way back to Aristotle’s On Rhetoric, it is a point in logic to prefer the simpler explanation over the more complicated one.

Furthermore, if the universe was created by multiple gods, these gods would have had to be created, which would hearken back to an even greater God, who would, in fact, be God.

3. The Argument from the Nature of God

From the moral and cosmological arguments, we’ve arrived at the concept of “God” as an infinite, uncaused being. Furthermore, because this God is the creator of the moral standard, God is thus perfect.

This leads to some issues if there is more than one being that fits the definition of “God.” 

Since God is a completely perfect being, there can’t be a second God, because for them to be different beings, they would have to be different in some way, and to differ from complete perfection would be to be less than perfect, and thus not God.

Furthermore, as the infinite uncaused being, this infinite uncaused being(s) can’t have parts (because parts can’t be added to reach infinity). Therefore, there can’t be two infinite beings, for one would have to differ from the other. They could not both be infinite.

4. The Argument from History

Clearly, something isn’t right just because a lot of people think it is. However, it’s interesting to note just how similar the ideas of God have been around the world throughout history. 

An early theoretical approach to anthropology, cultural evolutionism, holds that societies pass through developmental stages of improvement, from the primitive to the advanced. Sir James Frazer (1854-1941) was a notable figure in this theory and proposed that as people groups advance from “savagery” to “civilization” (as per E. B. Tylor), they also advance religiously, following the pattern of magic, to totemism, to animism, to polytheism, to monotheism, to science.

Unfortunately, though numerous issues have since been uncovered with this approach and it is largely supplemented or replaced by other views today, this idea seems to persist. However, this kind of development, described as an upward development toward monotheism, has never been observed within any culture. The opposite seems to be the case, and the alleged stages are often missing or skipped. The theory, as a whole, has shown to be problematic, especially since this method’s definition of “primitive” equates to technological development, hardly the only criterion on which a culture should be judged, and which has been linked to ethnocentrism and colonialism with anthropologists of Western cultures assuming their own cultures to be more “advanced” and thus the goal for other cultures. 

Instead of this idea that monotheism is a more developed belief, there is a good deal of evidence that it is the default. Most polytheistic cultures show vestiges of monotheism early in their development. From the “Apajui” of the Aguaruna of Peru to the “Wakan Tanka” of the Sioux people, tribal-based cultures frequently feature a supreme being who is personal, masculine, lives in the sky, has great knowledge and power, created the world, and, most interestingly, whom we have disobeyed and are thus estranged from, for which a way of reconciliation may or may not have been provided. 

Fascinating anthropological studies, such as the work of Dr. Robert Priest with the Aguaruna, have found a variation of this god in virtually every religion at some point in its past, even if it then morphed into polytheism. Thus, it seems that most religions have begun in monotheism and “devolved” into polytheism, animism, and magic — not vice versa. (Islam is an exception, having come full circle back into a monotheistic belief.) 

However, even polytheism is often functionally monotheistic or henotheistic. Most polytheistic religions hold one god above all the rest, whether the ancient Zeus of Greek lore or Shiva or Vishnu in Hinduism. Also, proximity to the main three monotheistic religions does not seem to matter; for example, the religion of the ancient Chinese Shang Dynasty (1600–1046 BC) featured belief in the Lord-on-High “Shangdi” long before Christianity or Islam existed.

It seems, then, that the most natural form of belief for humans is monotheism, whereas other forms of belief tend to arise after centuries of cultural evolution. Of course, this does not necessarily mean anything, but it adds to building a case for monotheism.

5. The Argument from the Bible

For Christians, the answer to monotheism is simple. The Bible clearly states that there is one God, supreme in power. Here are a few passages that support this:

You were shown these things so that you might know that the Lord is God; besides him there is no other (Deuteronomy 4:35).

Hear, O Israel: The Lord our God, the Lord is one (Deuteronomy 6:4).

Yet for us there is but one God, the Father, from whom all things came and for whom we live; and there is but one Lord, Jesus Christ, through whom all things came and through whom we live (1 Corinthians 8:6).

Further references include Ephesians 4:6, 1 Timothy 2:5, and James 2:19.

Christianity’s Unique Hope

Christianity is a monotheistic religion. We believe in one God, the God of the Bible. However, Christianity holds out the unique doctrine of the Trinity, one God in three Persons.

Our God sent His only Son, Jesus Christ, to take the punishment for our sin upon Himself so that we might live with God in eternity. What does it matter to us whether or not there is a God if we cannot reach Him? And yet, this discussion of monotheism proves to be of infinite importance, for the mighty One who created the universe also created a way that His creation might be called His friend (John 15:15).

©iStock/Getty Images Plus/Rawpixel

Alyssa Roat studied writing, theology, and the Bible at Taylor University. She has worked as a literary agent at C.Y.L.E., the publicity manager at Mountain Brook Ink, and as a freelance editor with Sherpa Editing Services. She is the co-author of Dear Hero and has 200+ bylines in publications ranging from The Christian Communicator to Keys for Kids.


Christianity / Theology / God / Can Monotheism Be Proven?