For Part 1 – Analogy in Theological Language
Given below is an analogy or model of the Trinity taken from the book, Philosophical Foundations for a Christian Worldview by J. P. Moreland and William Lane Craig. You may note that the model is a description of how the Trinity could be coherently conceived. It does not constitue a logical proof. The alert reader would also recognize that Moreland and Craig are merely defending one of several possible models of the Trinity.
In Greco-Roman mythology there is said to stand guarding the gates of Hades a three-headed dog named Cerberus. We may suppose that Cerberus has three brains and therefore three distinct states of consciousness of whatever it is like to be a dog. Therefore, Cerberus, while a sentient being, does not have a unified consciousness. He has three consciousness. We could even assign proper names to each of them: Rover, Bowser and Spike. These centers of consciousness are entirely discrete and might well come into conflict with one another. Still, in order for Cerberus to be biologically viable, not to mention in order to function effectively as a guard dog, there must be a considerable degree of cooperation among Rover, Bowser and Spike. Despite the diversity of his mental states, Cerberus is clearly one dog. He is a single biological organism having a canine nature. Rover, Bowser and Spike may be said to be canine, too, though they are not three dogs, but parts of the one dog Cerberus. If Hercules were attempting to enter Hades and Spike snarled at him or bit his leg, he might well report, “Cerberus snarled at me” or “Cerberus attacked me.” Although the church fathers rejected analogies like Cerberus, once we give up divine simplicity, Cerberus does seem to represent what Augustine called an image of the Trinity among creatures.
We can enhance the Cerberus story by investing him with rationality and self-consciousness. In that case Rover, Bowser and Spike are plausibly personal agents and Cerberus a tripersonal being. Now if we were asked what makes Cerberus a single being despite his multiple minds, we should doubtless reply that it is because he has a single physical body. But suppose Cerberus were to be killed and his minds survive the death of his body. In what sense would they still be one being? How would they differ intrinsically from three exactly similar minds that have always been unembodied minds, in virtue of what are they one being rather than three individual beings?
The question of what makes several parts constitute a single object rather than distinct objects is a difficult one. But in this case perhaps we can get some insight by reflecting on the nature of the soul. We have argued that souls are immaterial substances and have seen that it is plausible that animals have souls. Souls come in a spectrum of varying capacities and faculties. Higher animals such as chimpanzees and dolphins posses souls more richly endowed with powers than those of iguanas and turtles. What makes the human soul a person is that the human soul is equipped with rational faculties of intellect and volition that enable it to be a self-reflective agent capable of self-determination. Now God is very much like an unembodied soul; indeed, as a mental substance God just seems to be a soul. We naturally equate a rational soul with a person, since the human souls with which we are acquainted are persons. But the reason human souls are individual persons is because each soul is equipped with one set of rational faculties sufficient for being a person. Suppose, then, that God is a soul which is endowed with three complete sets of rational cognitive faculties, each sufficient for personhood. Then God, through one soul, would not be one person but three, for God would have three centers of self-consciousness, intentionality and volition, as social Trinitarians maintain. God would clearly not be three discrete souls because the cognitive faculties in question are all faculties belonging to just one soul, one immaterial substance. God would therefore be one being that supports three persons, just as our own individual beings each support one person. Such a model of Trinity monotheism seems to give a clear sense to the classical formula “three persons in one substance.”