Anyone familiar with the life and works of John Calvin is familiar with the name Michael Servetus. John Calvin had Servetus executed for the crime of slighting Calvin. Calvin long held a grudge against Servetus for what Calvin saw as a direct attack against Calvin’s teaching. Officially, Servetus’ crime was being a non-Trinitarian and anti-paedobaptism (anti-infant baptism), an evil enough reason in itself that Calvin should be condemned in history.
But besides a few choice disagreements with Calvin, Servetus seems to have been carried away with the same strain of Platonism affecting Calvin. From his book On the Errors of the Trinity:
For in himself God is incomprehensible; he can be neither imagined, nor understood, nor discovered by thinking, unless you contemplate some aspect in him. (Book 6)
Incomprehensibility is used in a sense that no one can know any aspect of God. Calvinists often try to claim this as some sort of boon to God, as if he is too high and mighty to even interface with humanity in any aspect, but this is wrong. God describes himself overwhelmingly by his relations to mankind, by his emotions, and even by his actions. God is not unknowable in the Calvinistic sense advocated by Servetus. That is pure Platonism.
Likewise, Servetus argues for God’s “unity” and “timelessness” and uses these platonistic notions to discount the trinity:
There was, then, an oracle, a hypostasis of God, a Person of CHRIST, the divinity which was Son to God alone. Yet to us Christ alone is called Son. The being was future to us; but to God nothing is future. There was in God the very image of a being that to us was future; as if I now saw in a mirror a being that is not, but will be tomorrow…
The glory of the Father is in his spirit to a much more exceptional degree than the light can appear in his face. It would then dim this manifold fullness of Deity to be contented with a mere union with the second being; nor can this be done, unless you make the Son separate from the Father, or remove the Father from CHRIST; for there is in him nothing that can be called Son save the Father himself alone; therefore CHRIST is called the Son, and the Father is in the Son. (Book 7)
It is a great tragedy that Michael Servetus was executed and that the execution was followed up with the attempt to wipe his works from history. But Servetus, for all his good, was another mold of Calvinist, an even more consistent Calvinist than are alive today. The mere notion of the trinity discounts “unity” and “simplicity”, the core of the Platonistic descriptions of God.