A Note on an Ontological Argument for the Trinity

The Son is co-eternal with the Father, in orthodox Christian belief. In that sense, God the Son must be a necessary part of the perfection of God. But why?

If matter is good, then “God the Son” as a “Son of Man” with a fully material human body must also be good.

If God must exist by Anselm’s ontological argument, because existence adds to his perfection, then existing in the bodily material plane as Christ the Son of God also adds to his perfection because of the goodness of matter.

But why then God the Holy Spirit? In a couple of possible senses, the third person of the Holy Trinity adds to the perfection of God. For example, having a community of equal persons adds to the perfection of God. A multitude of gods would not add to the perfection of god because of their diminution of the majesty and oneness of god. But having three persons in one God in a loving community does add to his power, dignity and goodness.

I have placed this sketch of an idea here too on Academia.edu

Some of my points above were developed in response to this Facebook post in the group Australasian Association of Philosophy, in relation to this suggestion: “The idea of God, by Anselmian definition, implies that God exists, for to exist in reality is greater than to exist in the understanding alone. But if that is so, then what of God’s idea of himself? As a perfect being, God’s idea of himself must be of a perfect being. But if to exist in reality is greater than to exist in the understanding alone, would not the object of God’s thought be greater if it existed in reality than if it existed in God’s understanding alone? If so, then Anselm’s argument might be an argument not just for one perfect being, but an infinite number of perfect beings. Or you might see this as a reductio against Anselm’s argument.”

This recent philosophy comic mentions St Anselm the theologian and philosopher.

23 responses to this post.

  1. Add to the Perfection of God? That assumes that He was lacking some perfection that an addition improved. That is contrary to Aquinas’ definitions. The ‘Material’ plane is a gift of God. It does not add to God’s perfection. It is an expression of God’s Unbounded Love. Christ is ‘Son’ (in our understanding) because he was sent by the Father, but that too assumes God being somehow subject to Time – a before and an after: a God before He sent Christ and a God after. But Christ, who is also God, and the Father who is also God, and the Holy Spirit, who is also God, existed in timelessness and eternity, without beginning and without end. This – all of it, and especially the Trinity – is a mystery.


    • Posted by Julian O'Dea on May 30, 2015 at 4:44 am

      Perhaps you need to read what I wrote as an extension of Anselm’s ontological argument, in which he argues that the existence of god is obliged by his definition as a perfect being.

      I gave a cite to the ontological argument.

      Thanks for your comment.


    • God is total perfection and does not need additional gods like the mythologies of creation do wants us to believe. The Word of God is given to us so that we may come to see who is who in this world and in the creation of the Only One True God, Whose Name is Holy and Who is the Father of Jesus and not Jesus himself.


  2. The son of God is not the same as god the son and the Bible is making it very clear who the Jewish man in the river Jordan was: the beloved son of god and not God Himself. According to the Bible there is only One True God and that its the God of Abraham, Who was also the God of Isaac, Jacob, Jesus and his disciples and should also be our God.


    • Posted by Julian O'Dea on May 30, 2015 at 11:21 am

      As I noted here, ” … the Son is eternal like the Father and the Holy Spirit. The belief that the Son was created by the Father is the heresy of Arianism.”

      Also, see here:

      According to this central mystery of most Christian faiths, there is only one God in three persons: while distinct from one another in their relations of origin (as the Fourth Lateran Council declared, “it is the Father who generates, the Son who is begotten, and the Holy Spirit who proceeds”) and in their relations with one another, they are stated to be one in all else, co-equal, co-eternal and consubstantial, and “each is God, whole and entire”. Accordingly, the whole work of creation and grace is seen as a single operation common to all three divine persons, in which each shows forth what is proper to him in the Trinity, so that all things are “from the Father”, “through the Son” and “in the Holy Spirit”. [emphasis added in bold]

      The same article cites scripture: “For in Christ all the fullness of the Deity lives in bodily form”.


  3. […] A Note on an Ontological Argument for the Trinity […]


  4. Posted by Julian O'Dea on May 30, 2015 at 10:38 pm

    And today is Trinity Sunday.


  5. Posted by Julian O'Dea on June 4, 2015 at 8:15 am

  6. Posted by Julian O'Dea on September 26, 2015 at 1:17 pm

    Douglas Gasking against the traditional ontological argument:



  7. Posted by Julian O'Dea on September 29, 2015 at 8:59 am

    Apparently this from Bishop Sheen contains some discussion on the “necessity” for angels to exist:


  8. Posted by Julian O'Dea on December 18, 2015 at 7:25 am

  9. Posted by Julian O'Dea on May 25, 2016 at 10:36 pm

    CS Lewis on the goodness of matter:

    “[God] uses material things like bread and wine to put the new life into us. We may think this rather crude and unspiritual. God does not: He invented eating. He likes matter. He invented it.”


  10. Posted by Zeta on May 26, 2016 at 12:37 am

    To us it appears to be material.To God nothing is material, it is all His energy. He is like an electrician who can use the same electricity to make something hot or cold.


  11. Posted by Julian O'Dea on August 19, 2017 at 2:18 pm


    See esp. for views on the Trinity.


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