The Trinitarian Doctrine
One first starts with what trinitarians actually believe about the doctrine of the trinity. First off, all trinitarians are monotheists. They all believe in exactly one God. Therefore they deny any form of polytheism. Second, all trinitarians believe that the historical person of Jesus is God, and that he is God is the same sense that the Holy Spirit and the Father are God. This means that all three are equally God. Therefore they deny any diminishing of the divine status of Jesus or the Holy Spirit. Third, all trinitarians believe that the Father, Son and Holy Spirit are distinct. Each one has a property that the other does not have, and each one is a person. (Both terms were defined by the trinitarian controversies.) These three points define the center of trinitarian doctrine. (I am ignoring the doctrine of procession because some trinitarians reject it.)
Any doctrine of the trinity will be a set of propositions that is the truth-maker of the above positions while not entailing any contradiction. Yet the three points above are not the actual doctrine of the trinity. Consider the Father, Jesus and God. According to the first point, there is one God. According to the second point, the Father and Jesus are both equally God. According to the final point, the Father and Jesus are distinct and have different properties. So the simplest reading of these points generates a contradiction. That means that the three points are not first-order propositions. They must be second-order propositions about unmentioned first-order propositions instead. One does not discuss the meaning of propositions, only whether they are true or false. One discusses the meaning of sentences.
So what are those three points? They are the way to recognize the actual doctrine of the trinity. Since these three points are true of the trinitarian doctrine, they are necessary to recognize that doctrine. Any doctrine these points are true of would be trinitarian, so these points are also sufficient. Therefore, these points are both sufficient and required to recognize trinitarian doctrine and to believe it indirectly.
Labels: christian theology, epistemology, philosophy of religion