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  • Writer's pictureJude

Aquinas’ Quinque viæ: Regarding the existence of God

Updated: Dec 28, 2023

The existence, magnificence and intelligent architecture of the World is often bluntly exemplified as the work of God. This bluntness doesn’t sit well with many considering we would be able to use God to illustrate the workings of almost anything. Those people who aren’t convinced by such curt answers may take interest in arguments like Aquinas’ Quinque viae, which is Latin for Five Ways. Aquinas’ Five Ways were summarised in his book Summa Theologica where he intended to prove the existence of a monotheistic God through these arguments. Since some of the arguments can be considered Cosmological, I’m going to present the Kalam Cosmological Argument then analyse the five ways.


The Kalam Cosmological Argument was first suggested by Aristotle but Muslim Philosophers Al-Kindi, Al-Ghazali and Ibn Rushd refined the argument hence it’s called “Kalam” which is Arabic for the study of speech. The argument is as follows:


  1. Everything that has a beginning of its existence has a cause of its existence.

  2. The Universe has a beginning of its existence.

  3. Therefore, the Universe has a cause of its existence.

That cause is deemed to be God.


Before I analyse the arguments it’s necessary to understand the term “infinite regress”.  An infinite regress is a series of propositions that require an answer for the previous ones actions. In example: A1 exists because of A2. A2 exists because of A3. A3 exists because of A4 etc. This becomes an infinite loop.


First Way

The Unmoved Mover argues that God set things in motion:

  1. Some things are set in motion

  2. A thing can’t move by itself without having a mover

  3. An infinite regress of movers is impossible, especially in the case of the Universe

  4. Therefore, there is an unmoved mover that sets everything in motion

  5. That unmoved mover is God


Aquinas attempts to use God to account for the presence of change in the World. This concept was influenced by Aristotelian physics which perused motion and changes in the physical World. In Summa Theologica Aquinas argues everything that is in existence was engineered by something before it, so the motion must be passed from one object to another. The use of the word mover doesn’t just mean physically move, but the characteristics of what has been moved can also be altered. He proposes an example of a Fire and a Log. When they meet the Fire will cause a reaction that changes the Logs characteristics and so the Fire is the mover of the Log.


Second Way

The First Cause argues that God must have been the initial cause:

  1. Some things are caused

  2. Everything that is caused is caused by something else

  3. An infinite regress of causation is impossible

  4. Therefore, there must have been an uncaused cause of all that has been caused

  5. That uncaused cause is God


Unlike the First Way, Aquinas takes a metaphysical approach to arguing for the existence of God as it considers the whole World. Aquinas uses the principle of efficient causation, which states every effect must have a cause, to justify this argument. Aquinas claims that an object in the World didn’t come into existence by itself or from nothing, it must have been caused. With this reasoning he states the World must have been caused by something  too, and that cause is God. Aquinas argued there must be a beginning to the change of causation because if there was no beginning, there couldn’t have been any succeeding links.


Third Way

The argument from Contingency is where Aquinas ponders ruminates over existence:

  1. Many things in the Universe may either exist or not exist and are all finite. Such things are called contingent beings

  2. It’s impossible for everything in the Universe to be contingent, for then there would be a time when nothing existed, hence nothing would exist now since there would be nothing to bring anything into existence which is obviously false.

  3. Therefore, there must be a necessary being whose existence is not contingent on any other being or beings.

  4. This being is God.


Aquinas clarifies that we witness things in nature that can exist and cease to exist. e.g. Human beings that existed at one point die and cease to exist. He argues that they can’t always exist because there was a point where we didn’t exist. e.g. Before we are born we cease to exist. Aquinas then argues if there was a point where everything existing now didn’t exist, then there must have been a point where nothing existed. If nothing existed, nothing would exist now. In that juncture of no existence, there must have been a necessary being that caused existence. Since it’s unintelligible to think of and infinite amount of necessary things he concludes that necessary being something necessary within itself – that being is God.


Fourth Way

The argument from Degree looks at examples in the World and their varying perfections:

  1. Varying perfections of varying degrees may be found throughout the Universe

  2. These degrees assume the existence of an ultimate standard of perfection

  3. Therefore, perfection must have a pinnacle

  4. This pinnacle is God


Aquinas is arguing that there must be an epitome of perfection. He explains that there are vast varying degrees in the World. Aquinas uses the example of varying degrees of heat, in which he thought fire was the hottest of them all. He uses this example and assumes that there must be a maximum standard of perfection for all these varying degrees, which he deems to be God.


Fifth Way

The Teleological argument argues the existence of God by looking at the intelligent design of things:

  1. All natural bodies in the World act towards ends

  2. These objects are in themselves unintelligent

  3. Acting towards an end is a characteristic of intelligence

  4. Therefore, there exists an intelligent being that guides all natural bodies towards their ends

  5. This being is whom we call God


Aquinas argues that things are candidly acting towards an end and this is conspicuous because they pursue the best results. He doesn’t provide an example of this, so I’m going to assume he meant something like the process of photosynthesis and give an example: A plant embraces the Sun and absorbs water into its roots. It creates oxygen and pollen which a Bee acts a courier for from a Male to a Female plant in order to enable that Female plant to create new seeds. The plant dies and the new seeds grow to continue the process.  He depicts these objects as unintelligent with intelligent characteristics and claims their comprehension comes from God.


Aquinas’ Five Ways are subject to many criticisms. One appraisal looks at the similarities in the first two ways, the structure is claimed to be the same except the words “moved” and “caused”. In defence of Aquinas, the First Cause argument looks at the cause of the World – it’s metaphysical unlike the Unmoved Mover argument which is simple physics.


He suggests several times that Infinite Regress is equivocal, however a counter argument proposed in the form of an analogy by J.L. Mackie shows how Infinite Regress can be comprehensible. Mackie offers the imagination of an infinite amount of Railway Carriages which are linked together on a Railway. For these Carriages to run there has to be engine. Although Mackie didn’t suggest this, that engine could be God.


Another refutation of the first two ways is Ockham’s Razor, which is the argument of necessity proposed by Ockham. He points out that it’s superfluous to trace the motion or cause all the way back to its original source. If we look back at Aquinas’ example of the Fire & Log we can see the superfluous nature of it. For example: The Burned Log was moved/caused by the Fire, the Fire was moved/caused by the Lightning, the Lightning was moved/caused by the clouds etc. It’s superfluous.


Hume thought it was illogical to argue from causes within the Universe to that of causes of the Universe. As an empiricist, he believed we would need to leave the Universe to observe the claim of an Unmoved Mover or Uncaused Cause which is preposterous. Similarly to Mackie, he also questions why infinity isn’t comprehensible to Aquinas. Hume believe as Humans that our understanding gives birth through fusion of concepts. e.g. An Angel, by taking a winged creature like an Eagle or a Bat and a Human being we can comprehend an Angel by fusing aspects of these things. Hume claims if we had never developed the notions of intelligence, benevolence and wisdom the idea of God would be different to what it is.

Kant also criticises the argument for its lack of empirical evidence. He claims that the principle of causation only applies to the World of our sense experience. So the causation of the Universe isn’t in our sense experience, therefore unintelligible. We can’t use this sense experience to judge something that transcends all.


Adding to the arguments of Hume and Kant, Modern Philosophers point out the First Cause Argument is flawed logically. It uses a quantifier reversal, which applies one conclusion to all due to the similarities. In example: Every player in this team has a wife. When describing the team, the person commits the misconception of quantifier reversal by then stating the team itself has a wife. This is the same logic used by Aquinas.


Physics also proves to be a refutation of the First Cause Argument, because there are some events without a cause. Such as radioactivity, the longevity of radioactive materials can’t be predicted.


The argument of Contingency contradicts the Cosmological Argument which works as its basis. It claims there is a necessary being that is necessary within itself, which likely means Aquinas’ was claiming it brought itself into existence. However one of the basic premises of the argument is that there isn’t a being that owes existence to itself, it was caused by something else.


Hume refutes the third way by examining the use of the term necessary existence. He claimed it doesn’t have a logical conviction of purely logical or mathematical arguments. In example he compares the use of God being described as something we can’t fathom as not existing to twice two not to be four. We can understand twice two is equal to four, but we can’t empirically understand Gods existence. It’s also a circular argument, like the Ontological Argument, due to the fact it assumes the conclusion in one of its premises.

The argument from Degree is described as the weakest of Aquinas’ five ways. It’s understandable that there are varying degrees, but that doesn’t mean there must be an absolute example of this. In his argument he also described the values of “goodness, nobleness” etc, but the measurement for what is the correct goodness  or nobleness varies.


For example: Polygamy is a crime in Western Societies, in Muslim countries Polygamy isn’t prohibited, in some countries Polygamy is encouraged. Aquinas’ also claimed fire has the most heat, but to his defence he didn’t know about astronomy to realise a Star is hotter than simple fire.


Ockham views on necessity can be used to argue against the Teleological Argument. Ockham argues things occur out of necessity. Like the process of photosynthesis I briefly explained earlier, plants produce Oxygen which allows us to breathe, it’s necessary for the Bee to pollinate as it’s collecting pollen for their colony to produce honey.


This can relate to an evolutionary standpoint too. Darwinism would argue that we have evolved over time due to natural selection. Natural bodies such as Humans, Animals, Insects, Fishes and Plants have adapted to allow the fittest and healthiest members to survive, passing down characteristics through genes. Darwinist’s would also argue that evolution can’t be considered to be intelligent because of the complexity and length it takes to adapt. An example of this is Tetrapod Evolution, which took place of millions of years.  Another argument from a Darwinist standpoint, is we’re operating towards an end, why would species be actively progressing?


Hume questions morality and suffering in the World. If the World was truly intelligently designed, suffering, illness, disease and pain would cease to exist. He argues again from the point of empiricism by stating we haven’t seen God build the Universe. In example, we see a Carpenter build a chair – we haven’t seen God create anything. Hume proposes that intelligent design is complex, and uses the example of a Ship which is created by many Shipwrights. He states the Universe could have been created in a similar way, maybe suggesting a team of lesser Gods that work together? Albeit it’s somewhat unintelligible.

Aquinas’ Five Ways includes too many flaws and powerful objections for me to accept it in any way, but I will still present my own thesis on everything I analysed.


However I meditate over the creation of these arguments and the time in which they were created which allows me to understand why they’re subject to so many refutations. Many people discredit the creators of these arguments through the use of Science which is quite unfair. I have seen Philosophers such as Aquinas and Anselm labelled as stupid for proposing such theories. I would rather those people consider that in Medieval times they lacked the helpful but also diminishing knowledge of Science we do hence their theories wouldn’t have been so empirically sound. I think I could use the refutations from these Philosophers to create a better argument that could be relevant today and so:


  1. Existence is simply Being

  2. Humans can’t physically comprehend anything out of Being, we can only come to an a priori conclusion.

  3. Even in death our physical remains are still a part of Being

  4. The Universe is described as the totality of Existence

  5. We have empirical evidence that shows the Existence of the Universe.

  6. It’s unfathomable to physically step out of Universe in order to understand its creation, we just have to accept this is the current limits of our actuality

  7. There must be something that conjured the Universe, which is described as the totality of Existence, which is described as simply Being

  8. To create Being, the creator must have been outside of Being beforehand

  9. Therefore, the creator must be able to step in and out of Being – or this creator could have created Existence and simply be holding together Being itself, making sure it runs smoothly like an infinite engine.

  10. The empirical evidence of the creator could be described as gravity

  11. This creator is what I believe to be God


Pondering about Gods existence, this is what I think. I’m not asking anyone to believe it – but consider for meditation.

What do you think about this summarised view of the Five Ways and the objections?


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