…Continuing our description of Trinitarian Analogies
Many theologians have looked to features of the human mind or psyche to find analogies to help illuminate the doctrine of the Trinity (hence the label “psychological analogies”).
Historically, the use of such analogies is especially associated with Latin (or Western) Trinitarianism, a tradition that traces its roots to Augustine, the great Father of the Latin-speaking West.
[Some have] suggested that we can find an analogy for the Trinity in the psychological condition known as multiple personality disorder: just as a single human being can have multiple personalities, so too a single God can exist in three persons (though, of course, in the case of God this is a cognitive virtue, not a defect).
Initially, it might seem that the analogy with multiple personality disorder is not [completely accurate]. After all, the personalities of those who suffer from the disorder might seem to be nothing more than distinct states of a single (albeit divided) consciousness that […] cannot be manifested at the same time.
It is far from clear that these criticisms are decisive. And, at least on the surface, these two analogies [(Social and Psychological)] seem to have a great deal of heuristic value, for both seem to present real-life cases in which a single rational being is nonetheless divided into multiple personalities or spheres of consciousness.
The Statue-Lump Analogy
The third and final solution to the problem of the Trinity that we want to explore invokes what might be called the “relative-sameness” assumption. This is the assumption that things can be the same relative to one kind of thing but distinct relative to another. If this assumption is true, then it is open to us to say that the Father, Son, and Holy Spirit are the same God but distinct persons. Notice, however, that this is all we need to make sense of the Trinity. If the Father, Son, and Holy Spirit are the same God (and there are no other Gods), then there will be exactly one God; but if they are also distinct persons (and there are only three of them), then there will be three persons.
The main challenge for this solution is to show that the relative-sameness assumption is coherent. This challenge has been undertaken by a number of prominent contemporary philosophers including Sir Peter Geach and Peter van Inwagen.
Consider Rodin’s famous bronze statue, The Thinker. It is a single material object, but it can be truly described both as a statue (which is one kind of thing) and as a lump of bronze(which is another kind of thing). A little reflection, moreover, reveals that the statue is distinct from the lump of bronze. For example, if the statue were melted down, we would no longer have both a lump and a statue: the lump would remain (albeit in a different shape), but Rodin’s Thinker would no longer exist. This shows that the lump is something distinct from the statue since one thing can exist apart from another only if they are distinct. (A statue cannot exist apart from itself!)
Now, it is difficult to accept the idea that two distinct things can be the same material object without some detailed explanation of what it would mean for this to occur. But suppose we add that all it means for one thing and another to be the same material object is just for them to share all of their matter in common. Such a claim seems plausible, and if it is right, then our problem is solved. The lump of bronze in our example is clearly distinct from The Thinker because it can exist without The Thinker, but it also clearly shares all the same matter in common with The Thinker and hence, on this view, is the same material object.
Cite: Brower & Rea, Understanding the Trinity, Logos: A Journal of Catholic Thought and Culture 8.1 (2005) 145-157