Kurt Gödel wrote a logical proof of God and hid it for decades
The first draft of Kurt Gödel's proof that God exists dates from around 1941, yet he told nobody until 1970, when he believed he was dying. Even then he refused to publish, reportedly afraid people would think he actually believed in God rather than merely testing what classical logic could prove.
The argument belongs to a long line of ontological proofs. Anselm of Canterbury argued that God is that than which nothing greater can be conceived, and that such a being must exist in reality, not only in thought. Gottfried Leibniz produced a more elaborate version, and that is the one Gödel set out to tighten using modern modal logic, the logic of what is necessarily or possibly true, usually pictured as truth across many possible worlds.
Gödel starts from positive properties. Of any property and its opposite, exactly one is positive, and whatever a positive property necessarily implies is positive too. From this he shows every positive property could be instantiated somewhere. He defines a Godlike being as one having all positive properties, and adds as an axiom that necessary existence is itself positive. Since a Godlike being has every positive property, it exists necessarily, so if it exists in one possible world it exists in all of them. He deliberately stopped at existence, not uniqueness.
In February 1970 he let the logician Dana Scott copy a version, which circulated privately; that August he told the economist Oskar Morgenstern he was satisfied with it. Gödel died on January 14, 1978, and the proof appeared in print only in 1987. Privately he was more devout than he let on. He argued for an afterlife in letters to his freethinking mother, called himself a baptised Lutheran with a theistic belief following Leibniz rather than Spinoza, and his wife said he read the Bible in bed on Sunday mornings. Among his fourteen philosophical theses was the claim that most religions are bad but religion itself is not.
Critics target the axioms, since a valid proof is only as convincing as its starting points. Jordan Howard Sobel showed they lead to modal collapse, meaning every truth becomes a necessary truth, erasing any difference between what is and what must be. Graham Oppy asked whether the same axioms would prove many near-gods, a challenge Michael Gettings disputes.
Source: Gödel's ontological proof
