Why the Trinity?

After sharing John Adams' quotation on a thread where many orthodox Christians participate, I got the question: Why the Trinity? What was it about that particular doctrine that so irked Adams and Jefferson? She raised a point to which I think fervent atheists like Richard Dawkins could assent: If one can believe in a God Himself, as these Founders did, what is so much more mysterious or irrational about the Trinity that it should be a deal breaker?

The answer, which I will reveal shortly, reminds me of the scholarly value of Gary North's ebook, "Conspiracy in Philadelphia."

Our Founders were influenced by literally hundreds of prominent thinkers who came before them often rattling off a plethora of names at once when explaining their ideas. Given so many citations to past authorities, scholars disagree on the level of importance to attach to each. Most agree on the primacy of Locke's influence, and disagree over how seriously other figures impacted our Founders. North has convinced me (what I think this book seriously contributes to the scholarly debate) that scholars underappreciate Isaac Newton's influence.

The Founders did cite him by name and otherwise greatly admired him; but they "lifted" far more from John Locke, Montesquieu, and others. Newton's influence was mainly in their worldview that he helped to shape. Like them, Newton was a unitarian, not a Christian. Why did he/they reject the Trinity? The Newtonian worldview believed that all Truth -- the natural law, scientific truth, moral truth, etc. -- could be "discovered" in the same way that mathematical formulas were "discovered." Hence theirs was a worldview dominated by math, geometry and architecture. One "built," if you will, nations and governments as one built physical structures. And indeed, their writings are replete with geometric and architectural metaphors; this also explains why Freemasonry with its "Great Architect of the Universe" God appealed to so many of them. Thus, with mathematical proofs like 2+2 = 4 playing such a prominent role in discovering "self-evident" Truths, anything that appeared to violate simple math (like 1+1+1 = 1) was likely to be held suspect or worse.