After presenting in Honduras on the evidence for intelligent design in the genetic code, and thus the necessity of a Designer of DNA (God), one observant lady asked a good question that evening. How do we know there’s only one designer? In other words, while the argument from design can bring us from atheism to theism, what’s to say polytheism isn’t really the best explanation? She’s right – the teleological argument from design that I was presenting can’t tell us if there were multiple designers, only that the design we observe required some designer. But it is quite common for any man-made project to be divided up among a design team. In fact, on almost every project I’ve worked on in my career as an engineer, I’ve simply been one member of a design team, dealing with my area of knowledge. So does the idea of a “divine design team” of gods bear up to scrutiny? I don’t think so, and here’s why.
Part of the strength of the case for the God of the Bible is the interlocking nature of the evidence. While the evidence from design doesn’t address this particular question, other line of reasoning do. First we have to look at the law of causality: everything that begins to exist has a cause. Anything that fits in this category is considered contingent because its existence depends on something prior – its cause. A design team of angels or “lesser gods” responsible for the design we see in different natural objects would simply be an intermediate link in the chain of causation. They might be immediately responsible for the objects we investigate, but if we go back far enough, we must eventually arrive at something that does not need a prior cause because it has always existed. They would ultimately need to trace back to a non-contingent source, which we would then call God. Even if God delegated the design of nature to a “design team” and did no specific design Himself, He would still be causally responsible for whatever was designed by them.
But one might ask if there could be multiple non-contingent beings. Let’s follow that line of reasoning. To be non-contingent (or metaphysically necessary) requires eternal existence in order to not have a prior cause. A necessary being cannot not exist, hence the title “necessary”. So this being can never cease to exist without all of reality that is contingent on him ceasing to exist at the same time. Therefore, no other being or group of beings could be more powerful than the one in question. For if any other being(s) could control or change the subject being, then its actions would be contingent on their actions, and he would turn out to not be a necessary being after all. For these reasons, you can’t have more than one non-contingent being in any possible reality. It’s also worth noting that the axiological argument shows that God exists due to the existence of objective moral values, which have to come from a source beyond humanity to truly be objective. But if multiple non-contingent beings existed, there would not be a single source for the objective moral values we observe. This is not to say that those values couldn’t have been established by consensus of a group of deities, but that does seem to multiply assumptions needlessly. I don’t know that we could say the axiological argument alone is sufficient proof of God’s uniqueness, but I would count it as contributing evidence.
But could we have necessary beings in different “dimensions”, “parallel universes”, or some other concept of separate but coexisting realities? This is basically just an updated idea of henotheism, the idea of locally supreme deities, applied to more abstract regions than the original geographical ones. If a god were all-powerful in his dimension, but limited to that dimension, then he wouldn’t really be necessary, even in that dimension. He would be, in effect, a caged deity contingent on that dimension’s existence and the higher deity who established that dimension. A truly necessary being must transcend all possible worlds/dimensions/realities to not be contingent.
In the end, we come to the conclusion that if God exists, He must be a non-contingent necessary being in any possible reality. We can look at the teleological argument (from design) and the various cosmological arguments (from causality) to see that God exists. Then we can look at the axiological argument (from morality) and ontological argument (from being) to see that polytheism is false and the Bible is correct when it says that “there is no God but one. For even if there are so-called gods whether in heaven or on earth, as indeed there are many gods and many lords, yet for us there is but one God, the Father, from whom are all things and we exist for Him; and one Lord, Jesus Christ, by whom are all things, and we exist through Him.“
 1 Corinthians 8:4-6, NASB.