How Do We Know God is One? A Philosophical and Theological Perspective – Ask A Muslim

How Do We Know God is One? A Philosophical and Theological Perspective

(part 1 of 3)

One of the many common questions that were asked during the Islamic Awareness Tour was “If God does exist what reasons do we have to believe He is one?” This question is important as it addresses a fundamental concept in Islamic theology, the concept of God’s oneness. The oneness of God, in Arabic Tawhid, is a central theme in the Qur’an and is the message of all of the Prophets. The Qur’an eloquently describes the nature of God and His oneness in the 112th chapter,“Say: He is God, the One. God is the One upon whom all creation depend upon for their sustenance. He begot no one nor was He begotten. No one is comparable to him.”

Before I begin to answer the question, it is important to add that the concept of oneness in Islam is not limited to God’s singularity and uniqueness. There are many aspects to this concept which involve the way human beings should worship God, how they should understand His lordship, and how they should understand God’s names and attributes. It doesn’t stop there as these ideas transform an individual’s world view and outlook, as a famous Asian-subcontinent thinker once wrote,
“A believer in this…can never be narrow in outlook. He believes in a God Who is the Creator of the heavens and the earth, the Master of the East and the West and Sustainer of the entire universe. After this belief he does not regard anything in the world as a stranger to himself. He looks on everything in the universe as belonging to the same Lord he himself belongs to. His sympathy, love and service are not confined to any particular sphere or group. His vision is enlarged, his intellectual horizon widens, and his outlook becomes as liberal and as boundless as is the Kingdom of God. How can this width of vision and breadth of mind be achieved by an atheist, a polytheist or one who believes in a deity supposed to possess limited and defective powers like a man?”

In light of this there are many ways to answer the question referring to God’s singularity and uniqueness, thereby providing a positive case for the oneness of God, and they range from theological to philosophical arguments. I will present the following 5 arguments:
1. Occam’s Razor
2. Logical Argument
3. Conceptual Differentiation
4. Uniqueness
5. Revelation


Occam’s Razor

The Qur’an rhetorically asks the question “Did the universe come out of nothing?” The answer seems quite obvious due to the metaphysical and undeniable logic that whatever begins to exist has a cause, and since the universe began to exist, therefore it must have a cause. It would be irrational to posit more than one cause for the universe, as an infinite regress of causes is impossible. The reasons for this include the absurdity of the actual infinite existing in reality; take the following examples into consideration,

1. You have an infinite number of people in a room, if I take two people away, how many do you have left? The answer is infinity minus two. However does this make sense? If there are less than an infinite number of people in a room you should be able to count that number in the real world. But you can’t, in other words the infinite doesn’t make sense in the real world. In light of this Mathematicians Kasman and Newman state “The infinite certainly does not exist in the same sense that we say ‘There are fish in the sea’”.

2. Imagine I am a soldier and I want to shoot an enemy. In order for me to shoot I have to ask permission from the soldier behind me to shoot, but he has also has to ask permission from the soldier behind him to shoot, now imagine this continued forever, in other words an infinite amount of time? Will I ever shoot the enemy? The answers is plain obvious. In the same light an infinite regress of causes for the universe would mean there would be no universe in existence in the first place.

So the conclusion that the universe has a single independent uncaused cause seems quite plausible, however you can still posit a plurality of causes all occurring at the same time. Is this a sound argument? I believe it is not a strong argument if we take Ockham’s Razor into consideration. Ockham’s Razor is a philosophical principle attributed to the 14th century logician and Franciscan friar William of Ockham. This principle enjoins “Pluralitas non est ponenda sine necessitate”, in English “Plurality should not be posited without necessity.” In other words the simplest and most comprehensive explanation is the best explanation.

Essentially it means that in absence of any evidence or in absence of a need for a plurality of causes we should hold onto the most comprehensive and simple explanation. In this case we have no evidence to say the cause for the universe is actually a combination of two, three or even one thousand causes so the simplest and most comprehensive explanation is that this cause is one. Postulating a plurality of causes does not add to the comprehensiveness of the argument. In other words to add more causes would not enhance the argument’s explanatory power or scope. For example, to claim that the universe was caused by an all powerful cause is just as comprehensive than to claim to was caused by two all powerful causes. Because one all powerful cause is all that is required, simply because it is all powerful.

A contention to this argument is that if we were to apply this principle to the pyramids in Egypt we would absurdly adopt the view that it was made by one person. However, this is a misapplication of the principle. Taking the view that the pyramids were built by one person is actually not the simplest and most comprehensive explanation as it raises far more questions than it answers. For instance, how can one man build the pyramids? It is far more comprehensive to postulate that it was built by many men. In light of this, someone can say that the universe is so complex that it would be absurd to postulate that it was created by only one being. This contention, although valid, is misplaced. A powerful being creating the whole universe is a far more coherent and simple explanation than a plurality of causes. Now the critic may continue and argue that the pyramids could then have been built by an all powerful being. But the problem with this is that nothing within the universe is an all powerful being, and since the pyramids were built by an efficient cause (a person or persons that act) then it follows it must be of the same type of cause.


(part 2 of 3)

Logical Argument

Logic necessitates that if there were more than one God who created the universe it would be in chaos and there would not be the level of order we find in the cosmos. However you may point out that your car was made by more than one creator, one person fitted the wheels, and someone else installed the engine and another person the computer system. So from this example there can be more than one creator with the created thing still able to exhibit order and stability.

In order to respond to this contention what has to be understood is that the best explanation for the origins of the universe is the concept of God and not ‘designer’ or ‘creator’. There may be a possibility of multiple designers or creators, as highlighted by the car example, but there cannot be more than one God. This is because God by definition is the being that has an unlimited imposing will, if there were two or more Gods that would mean that they would have a competition of wills and that would result in chaos and disorder. However you may argue that they can agree to have the same will or each have their own domain, but that would mean that their wills are now limited and passive, which would mean they are not Gods anymore by definition!

This is explained well by Ibn Abi Al-Izz in his commentary of ‘Aqeedah at-Tahawiyyah’:
“The most common argument they advance is known as the argument of exclusion. This argument runs like this. If there were two creators and they disagreed about something, such as one wanted to move X, whereas the other did not want it to move, or one wanted to make Y a living being, whereas the other wanted to make it lifeless, then, logically speaking, there are only three possibilities. First, the wills of the two are both carried out; second, only the will of one of them is carried out; third, the will of neither of them is carried. The first case is not possible because it requires the existence of contraries. The third possibility is also ruled out because it would imply that a body is neither moving nor not moving and this is impossible. This would also imply that both of them are incapable or carrying out their wills, which would disqualify them from being God. Finally, if the will of one is realised and not that of the other, he alone will deserve to be God and the one whose will is not realised cannot be considered God.”


Conceptual Differentiation

What makes us appreciate difference and duality? How do we differentiate between two people walking in the street? The answer lies in what is called conceptual differentiation. These concepts include space, distance, form, and physical features. Take the following diagram into consideration,
The reason you can perceive two objects above is due to differences in colour, size, and shape, including their placement, in other words there is a distance between them. In absence of these concepts could you perceive the two objects or any objects at all? You could not, because these concepts are required to perceive any number of entities. Now since the cause of the universe is outside the universe (if the cause was part of the universe it would mean that the universe created itself, this is absurd as it would necessitate the universe to exist and not exist at the same time!), you can safely assume that there are no conceptual differentiators such as distance, shape, colour and size; because these concepts only make sense within the universe. Therefore if there are no knowable conceptual differentiators we cannot claim a multiplicity of causes, as I have explained above the impossibility of perceiving plurality or multiplicity in absence of these concepts.

Since you have no concepts to acknowledge a plurality of causes does this mean that even a single cause can’t exist? No it doesn’t, because if there were no cause for the universe then that would mean the universe, in the words of Bertrand Russell, “Is just there and that’s all”. In other words it would mean the universe is infinite, however this cannot be the case, as mentioned above the universe began to exist.

Therefore a single independent cause is rationally necessary to explain the fact that the universe began to exist and that a plurality of causes cannot be perceived due to the absence of conceptual differentiators.



The cause of the universe must be unique, as the Qur’an says “There is nothing like Him”. If the cause of the universe was not unique that would mean there are some similarities between the cause of the universe and the universe itself. This is not possible as that would place the cause of the universe within the universe (if you define the universe as the sum of all matter) and this would lead to an absurdity as it would imply that the universe created itself. Now you may ask the question: why can’t the cause of the universe resemble the universe? The answer is straight forward; this cause must be immaterial because it created the sum of all material – which is the universe itself – and another principle that supports this is the 1st law of thermodynamics, it states “Energy cannot be created or destroyed”, simply put energy (in other words matter) cannot create itself. If the cause was material then it would defy this principle as it would mean matter and energy self create. So you can conclude that the cause of the universe must be immaterial and therefore unique.

How does this relate to the oneness of God? Well if there were more than one cause for the universe that would mean they are not unique anymore. However you may still argue that there can be two immaterial causes, and I would reply: what does that mean? It would seem that you are violating Occam’s Razor and I would refer you to the first argument.


(part 3 of 3)


A simpler way of providing evidence for God’s oneness is by referring to revelation. The argument here is that if God has announced himself to humanity and this revelation can be proven to be from Him, then what He mentions about himself is obviously true. The daring assumptions, from an agnostic perspective at least, are how do you know God has announced himself to mankind and in what form is this revelation?

Let’s take the last assumption first. If God has announced himself to mankind there are only two possible ways to find out: externally and internally. What I mean by “internally” here is that you can find out who God is solely by introspection and internalisation and what I mean by “externally” is that you can find out who God is via communication outside of yourself, in other words it is instantiated in the mind-independent world. Finding out about God internally is implausible for the following reasons,

1. Human beings are different. They have, what Psychologists call, “individual differences”, these individual differences include DNA, experiences, social context, intellectual and emotional capacities, gender differences, amongst many more. These differences play a role in your ability to internalise via introspection or intuition, therefore the results of introspection or relying on your intuition will differ. So you can see that if these processes were solely used to find out about God there would be inevitable differences in our conception of Him. This is true from a historical point of view, since the ancient world 6000 BCE, there are records of approximately 3,700 different names and concepts for God!

2. Since the method used to conclude that God does exist is a “common sense” method, or what philosophers call rational thought and w hat Muslim theologians may call innate thinking, then internally trying to find out about God would lead to fallacies. This is because what can be concluded using the universe as evidence for a transcendental independent cause is that it must be eternal, unique, powerful and personal; anything else would be speculation. The Quran aptly mentions “Why do you say about God of that which you have no knowledge?” If you try and internalise what God is would be equivalent of a mouse trying to conceptualise and think like an Elephant. It is obvious that the human being is not eternal, unique and powerful, therefore the human being could not conceptualise who God is. God would have to tell you via external revelation.

Take the following example into consideration, you know God exists like the knocking of the door, you safely assume that something is there, but do you know who it is? You weren’t expecting anyone, so you cry out “who is it?” in order to find out, and the only way to find out is if the person behind the door tells you. So you can conclude that if God has said or announced anything it must be external to the human being.
From an Islamic perspective this external communication is the Quran as it is the only text to claim to have come from God that fits the criteria for a divine text[1], these criteria include,

1. It must be consistent with the rational and intuitive conclusion on God. For example if a book says God is an Elephant with 40 arms you could safely assume that this book is not from God, as God must be external to the universe.

2. It must be internally and externally consistent. In other words if it says on page 20 that God is one and then on page 340 its says God is 3 that would be an internal inconsistency. Additionally if the book says that the universe is only 6,000 years old then that would be an external inconsistency as reality as we know it s that the universe is older the 6,000 years.

3. It must have signposts to transcendence. In simple terms it must have evidence to show that it is from God.

In the case of the Quran – and this post is not the place to discuss this in any depth – cannot be explained naturalistically therefore supernatural explanations are the best explanation. Some of these signposts include:
a. The linguistic and literary inimitability
b. There are historical accounts that could not have been known by man at the time of revelation
c. There are some descriptions of natural phenomena that could not have been known by man at the time of revelation
To conclude, since the only way to know what God has announced to mankind is via external revelation, and this revelation can be proven to be the Quran – then what it says about God is true. In the context of this discussion the Quran says “Know that your Lord God is one”.



These are some of the arguments that can be used to show that God is one; however this topic – once truly understood – will have some profound effects on the human conscious. The oneness of God is not only related to the fact that He is uniquely one, rather it refers to His worship, lordship, names and attributes, something that can only be tasted by pondering on reality, meditating on the meaning of the Quran, and becoming a manifestation of its message.

[1] The Quran is the only unchanged Word of God. Previous revelations of God have either been lost or altered.



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