I was reading about apologetics the other day and read as part of the causal argument for God's existence that there cannot be more than one necessary being (cause), meaning that there is only one God, for a being that is so perfect to the point of being necessary must be wholly perfect. I also read that Avicenna (I think) said that a necessary being is pure existence, meaning that existence is the only thing there is to its being, and that multiple necessary being would be identical and, therefore, one.

However, I've still been struggling for solid couple months to understand why the fact that there is only one God follows from the fact that first causes, or beings, are necessary. What is the connection between there existing only one God, necessity and identity of multiple necessary causes, if multiple? Why would multiple necessary beings need to be identical and, therefore, one? I've looked into the Stanford Encyclopedia of Philosophy, Roger Scruton's lectures, William Lane Craig's works and just plain Google, and couldn't find the answer. A similar but slightly more general question was asked here, but the answers were related to simplicity of argument, questioning its validity, or about things we encounter contingent things in everyday life, none of which actually helped me.

Thanks in advance!


  • Possible duplicate of Aquinas' Third Way: Why Argue For Only One Necessary Entity?
    – virmaior
    Jun 18, 2017 at 13:51
  • I actually looked at this thread before posting mine, but by asking the question in the context of Aquina's third way, the author of the question led to a broader discussion related to the existence of contingency beings and unfoldings of Aquina's third way. Because that question is broader, an answer to the question I asked was one of possible answers and , in fact, wasn't there. Should I have stated my question there as a comment, instead? I, personally, still find my post useful given the amount of essays I've read that discuss other parts of that thread but not specifically my question. Jun 19, 2017 at 14:42
  • No, you are fine, we are not that hasty. If he was sure this was a duplicate, it would have been a 'close' vote, instead if a comment for you to consider. (Even then multiple people, usually from 3 to 5, should agree that the post did not add anything of interest before someone actually closes it.)
    – user9166
    Jun 19, 2017 at 15:23
  • Oh, sounds good. This was my very first question posted here, so I'm glad I didn't screw up :) Jun 19, 2017 at 17:41

5 Answers 5


If you had two necessary things, their identities would depend upon their distinction from one another. Both of them would then be contingent upon one another, and neither would be absolutely necessary.

The distinction can clearly still exist: God has three persons. But it would not be part of the definition of the necessary thing.

This is not an analysis particular to Christianity, or even to monotheisms in general. Hinduism remains polytheistic but also has a unified necessary Godhead. Likewise, Plato spoke of a single God, but included prayers in his works to different Greek gods.

  • 1
    I wonder how one relates your first sentences to the concepts of yin and yang. Those two seem different enough that they might be a counterargument.
    – Cort Ammon
    Aug 12, 2017 at 3:00
  • @CortAmmon And they are part of a larger whole.
    – user9166
    Aug 12, 2017 at 17:09
  • The interesting question is whether that greater whole us something that can be talked about. After all, the Dao that can be talked about is not the eternal Dao.
    – Cort Ammon
    Aug 12, 2017 at 19:26
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    @jobermark You are making the false assumption that in order for there to be two of something, that there need exist a criterion by which they can be distinguished. This is factually false and has been known to be false for a long time with regards to many actual physical objects such as elementary particles (en.wikipedia.org/wiki/Identical_particles) and hence it is not a logically necessary statement but merely a misguided notion of human intuitive belief. Ultimately the claim that there cannot be two or a thousand necessary beings is not logically necessary at all.
    – MM8
    Aug 13, 2017 at 12:29
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    Take two spatially sufficiently separated electrons. Your classical "normal ontology" will try to argue that these are distinct because they are distinguishable by their spacetime separation. This is not a true distinction, however, it's merely an illusion. Factually, if the two electrons were exchanged instantaneously, it is in principle impossible to distinguish the state prior to this exchange from the state after this exchange. In other words, the spacetime separation does not allow you to distinguish between them without additional, logically not necessary assumptions.
    – MM8
    Aug 16, 2017 at 2:51

The connection is a theological necessity to get from 'the universe has a cause' to <insert preferred god-belief here>.

I have yet to find a compelling logical reasoning to support that jump, beyond biblical references and unsupported claims that it MUST be so. Ultimately, I find the claims that whatever cause was behind our universe must be a personal, sentient, omniscient being unconvincing.

It's all well and good to hypothesize at what might have been, but people are notoriously bad at acknowledging where the facts stop and the guesswork starts.

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    1.) I agree, and find there is no real logical justification for that 'necessary' being being a single one. The original forms of this argument (ala Plato/Aristotle) had this 'prime mover' as part of a pantheon of deities, and usually not a particularly notable member; 2.) I tend to tackle philosophy from a science-based, logical angle. Part of that is noting where the provable, tested evidence is, and being very careful where rhetorical/logical arguments attempt to justify things the original evidence doesn't actually speak to. Jun 19, 2017 at 20:18
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    This is not related to the question, so it is not an answer. This logic is part of 'the universe has a cause', and before the jump to which you object, or you would not say 'a cause', you would presume only that there are 'causes'. Your objection is reasonable, but it is not related to this particular argument at all.
    – user9166
    Jun 19, 2017 at 22:18
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    Thanks for the feedback, but I disagree on this answers applicability. The claim of there being only one creator stems from the same theological ties that causes the jump from a undefined 'cause' for the universe to a sentient god agent. Those logical leaps are present because the outcome of this exercise must lead to a god consistent with their already held beliefs. Because this is apologetics we're talking about ;) Jun 19, 2017 at 23:28
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    I think what jobermark meant is that the question was about the argument as opposed to its validity. Even though the arguments for God being necessary and sentient are related to the notion of causation, they are in two separate branches, if you will, trying to prove two different things, although interrelated. Jun 20, 2017 at 22:21
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    I can see that. I'll leave my answer for (negative) posterity, and see if I can whip it into something more inline with what's actually being asked at a later time. Thanks to both of you for the advice. Jun 21, 2017 at 4:11

There is only one necessary being because there is only one concept of "necessari-ness," to which the necessary being belongs, by virtue of its being "necessary," and in which it logically and ontologically partakes.


An answer to this question may be found by defining the fundamental conceptual abstraction the existence of God is likely to represent. Consider the following passages from an article entitled A Biblical Model of Human Dignity: Based on the Image of God and the Incarnation by John Roskoski PhD.

The question of the relationship between an individual and the group has existed since antiquity. One could say that a form of this question is the basis for the thought of the original Philosopher, Thales (c. 600 BC), who framed the problem of the “one and the many”. This is the problem of identifying the Ultimate Reality (One) that underlies all things and how the many entities relate to and derive from the Ultimate Reality.


Theologically, this resonates in the words of Revelation 1:8: “I am the Alpha and the Omega, the One who is and who was and is to come. . .” This deals with the totality of time and the natural world. The consistency of the “Kalam” model and the Revelation text with the name of God, YHWH, revealed to Moses (Exodus 3:14) must be observed. Following W.F. Albright, most scholars accept that the rendering of the Divine Name as denoting the “cause of all existence”. In this Name, we see the concept of this totality emerging.

The common theme in these two passages relates to the possibility the origin of God as a concept is a purposeful abstract representation of the totality of all existence as a single entity which includes both the known world and all things unknown or as of yet unexplained; a method for the examination of existence to determine the unity of reality or the one true existence. These references are undeniable in their emphasis of a singular empirical model.

Please find A Biblical Model of Human Dignity: Based on the Image of God and the Incarnation at http://www.biblearchaeology.org/post/2013/10/23/A-Biblical-Model-of-Human-Dignity-Based-on-the-Image-of-God-and-the-Incarnation.aspx for further reading.

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    Hello and welcome to philosophy.se! Do you think that you could expand this answer? The most well received answers on this site are the ones that have more than a few sentences to say, especially when they contain references and quotations to support what they say. Has any philosopher argued for what you are saying here? How would you contextualize what you're saying into a larger discussion containing the ideas you're arguing for as well as the opposite view? How would that relate to the OP's question? In general, short answers are not received well in terms of voting.
    – Not_Here
    Aug 12, 2017 at 3:42
  • Post has been edited based on the suggestions by the commentor.
    – Starrdaark
    Aug 13, 2017 at 9:16

As jobermark notes above, logical analysis determines that only one entity can be necessary or absolute. This is not a religious claim but a formal metaphysical one. To claim that this one entity is God would require an additional argument.

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