The so-called argument from the one and the many is a hallmark aspect of classical Van Tillian apologetics. Having studied this school for the last ten years, I am very acquainted with its methodology and published works. However, once one moves into patristics and Catholic and Orthodox theology, and then into other religious philosophies, the argument as constructed in writers like Van Til, Rushdoony and Bahnsen no longer works. This is not to say, however, that the argument has no relevance: on the contrary, in my estimation, it still retains its strength as a powerful signpost pointing to the Personal God of the Bible. However, I don’t think it proves the Trinity.
There are two reasons the one and many argument doesn’t to prove the Trinity. For one, Van Til wasn’t the first to reason in this regard: many earlier Christian thinkers and church fathers had argued along similar lines, such as Origen, Irenaeus, Basil and the Cappadocian, Maximus the Confessor, and others even in other religions, as we see in the Coomaraswamy article on Vedic Exemplarism. What is interesting in Maximus though, is that from the created one and many we experience, it does not prove or point to a single divine ousia and three Persons, but rather a single rational Principle of God – the Logos, the second Person of the Trinity, in whom all the many logoi, or rational principles/meanings of things are united. So for Maximus, drawing on Origen, the many logoi are one in the one Logos of God. This argument arose historically in the context of Hellenic Christianity borrowing the Logos idea, and was transformed into an argument for the necessity of creation through the Logos. In other words, the one and many argument is an argument centered in divine exemplarism.
As noted, this argument is utilized in the Vedas of Hinduism, as exemplarism has a very ancient forte. It is also mentioned in the Jewish Encyclopedia under “Logos” and in Jewish theologian David Ariel’s “What Do Jews Believe?” as an example of the fact that all that exists, exists by God’s own word. Everything is, in certain strands of Jewish thought, a reflection of Torah, the divine wisdom. So the argument is not something new to Van Til, as is clear. It is directly connected with divine exemplarism, and in fact, in Van Til’s Lectures in Christian Epistemology, he affirms his acceptance of Augustine’s version of divine exemplarism. But further difficulties arise in these thinkers, since even in the Eastern Fathers, so prized for their “necessary distinctions” in God, we find statements where the Logos is identified with the “mind of the Father” and that the Son “is the will of the Father,” as Athanasius and Nyssa say, for example. How this can be in strict Eastern theology is unclear, since it’s obviously anthropomorphic.
This brings me to the other reason the Van Tillian version of this argument doesn’t work – it identifies an ultimate principle of oneness with the divine essence. In the reformed presuppositional version of this argument, the supposed ultimate many is subsumed in the three Persons, while the ultimate unity of reality is subsumed in the single divine nature. Thus the argument for the so-called “equal ultimacy of the one and the many.” But the divine nature is not the equivalent of some ultimate “oneness.” The divine nature is not like anything else, has no “definition,” and is fully indescribable. There is no summing up of all things into an ultimate unity that is the divine nature.
It is fine to say that the sum total of all reality – ultimate created oneness – is subsumed in God, but this doesn’t mean “one” has any real defining power by which we can, through rational inquiry, equate it with God’s essence, and set it over against the “threeness” of the Persons. Further, this ignores the historic Christian position that the Father is the source of the Godhead; not abstract “oneness.” Further, the argument as posed by Maximus shows that it’s perfectly resolved in one divine Person – in his case, the Logos. But were a Jewish or Muslim theologian, for example, to argue that since it can be resolved in one divine Person, and not three, it’s a non sequitur to say we need three, I would have to concede the argument. Therefore, the argument as formulated by Van Til as a proof for the Trinity doesn’t work.