“trinity” = “tri” + “unity”: 3 different, but all 1
This has long been a problem for mortal minds, and many descriptions of it have been wrought. What I would like to suggest is that you should step out of the problem for a moment, and consider something else.
Let us imagine that there is a being who is omnipotent, all-powerful. As a result of its omnipotence, this being is also omniscient, all-knowing (knowing is a form of doing). Because it is omniscient, it knows
now what it will know in the future, what it will think, what it will feel, and what it will do. It lives that future now. It also lives the past now, and it always has done so. Thus, its time-frame folds together into one single, instantaneous, perpetual moment of everywhen.
Now, let us imagine another such omnipotent being in the same universe. Because both are omnipotent, both will have
complete knowledge of the other’s mind. In fact, both will effectively
live the other’s experience, through knowing it completely. They do not share a
will: each has the capacity to choose its own way. However, being so very close, they do not even need to
speak, because each is utterly aware of the yearnings of the other’s heart.
In the same way, the Spirit too comes to the aid of our weakness; for we do not know how to pray as we ought, but the Spirit itself intercedes with
inexpressible groanings (
Romans 8:26.)
Add one more such being.
This, I think, is the Trinity. Each lives the experience of the others, and so they are united, but each has a separate will, and so there are three.