Evidential decision theory was used way earlier than I would have expected, and its development was motivated theologically.

Unconditional election is the Protestant (mainly Calvinist and Puritan) idea that God made the decisions of who would go to heaven and hell before He created the world (very similar to predestination). It is "unconditional" because nothing you do in your life can change the outcome of whether you go to heaven or hell.

If you believe in this unconditional election, then you face a dilemma: "if election is unconditional and grace is irresistible, then why not sit back and wait for the inevitable?" (Stearns and Brawner, “New England Church ‘Relations’ and Continuity in Early Congregational History”, 30). If this is the case, where did the term "Puritan work ethic" come from? Why were the Sepratists so religious? According to Stearns and Brawner, prayer was used to find out if you were "elected":

The simplest and perhaps most satisfying method of dealing with this question was that of examining closely personal experience for signs of election. If an anxious Christian could find assurance that the seeds of regeneration had been planted in him, he could then be urged to labor with the Holy Ghost to bring forth the fruits of sanctification and thus participate actively in the work of his own redemption. But the spiritual physicians could not administer real comfort unless they could demonstrate convincingly that the symptoms of true faith and repentance were distinguishable from the simulacra produced by hope and fear. To this end they labored diligently. In 1592, William Perkins published a work entitled, A Case of Conscience, the greatest that ever was: How a Man may know whether he be a Child of God or No. The years that followed witnessed a great volume of sermons and treatises addressed in whole or in part to the same question. This literature may properly be called scientific, in the modern sense of the word, because it proceeded from the premise that the human will is a passive agent of the Holy Ghost—just as in modern psychology, the will is a passive agent of equally mysterious pneuma, labelled id, libido, etc. Puritan casuistry, in other words, was a branch of the science of pneumatology. It was not primarily concerned to chasten hypocrites (for hypocrites and true believers alike were caught up in the same inexorable determinism), but to identify the phenomena of rebirth, and to separate these from what today we would call auto-suggestion and wish-fulfillment. These phenomena were sorted out and arranged in normative, episodic sequences with which individual Puritans could compare their own experiences. In addition, rules of thumb were worked out by which the authenticity of individual experience could be tested.

These norms and rules of thumb—which Morgan sums up as the "morphology of conversion"—were applied to Bay Colony Congregationalist standards of admission in the form of the church relation." By listening to a brief account of a candidate's spiritual experience, and by occasionally asking well-chosen leading questions, expert examinersinitially the church elders—could quickly decide, on grounds well-laid, whether the candidate was, in Perkins's words, "a child of God or no." Thus, the church relation was a seventeenth century forerunner of the Rorschach, or ink-blot, test, by which a trained technician can make a sketchy but comprehensive assessment of the salient features of his subject's personality. (Stearns and Brawner, n.d., 30-31).

Taking the idea further, the Puritans wanted evidence that they were elected (Heyrman n.d.). And since humans essentially have free will (even if we don't actually), we can create evidence. The Puritan work ethic comes from the idea that "the Puritan sought success as evidence of his election to eternal bliss" (Griswold 1934, 476). The Puritans were allowed to work hard (and charge interest on loans) because God allowed them. If they were sucessful, surely they were "elected," and if they were not elected, God would make them unsucessful. Put another way, being sucessful was evidence that they were "elected," so they should strive to be sucessful.

This logic is isomorphic to Newcomb's Problem. The money (or heaven) is already in the box. Omega (or God) can not change the outcome. You can gain more utility by opening both boxes (or "sitting back and waiting for the inevitable"). You can choose to make the decision that someone who Omega thought would one-box would make (or the choices that God knew you would make if you were "elected").

We can use this as a case study to see what happens when someone actually believes an exotic decision-theoretic paradox deep in their bones. They one-box.

There are a few reasons this might not be that good of a case study. First, in the case of the Puritans, does two-boxing (living a life of laziness) actually provide more utility? The Puritans seemed to think being lazy and unpious provided them with more immediate-term utility, but to me, it's unclear. Second, most people were not thinking for themselves; they were following the preists and theologans. Finally, the theology evolved and most Christians today do not believe in unconditional election.

When I made the connection between the Puritans and evidential decision theory, I was really surprised. Investigating it more, it feels slightly more natural. Of course, it's still quite impressive and is a testament to how much intellectual progress can be made under totally false assumptions.

References

Griswold, A. Whitney. 1934. “Three Puritans on Prosperity.” The New England Quarterly 7 (3): 475–93. https://doi.org/10.2307/359674.

Heyrman, Christine Leigh. n.d. “Puritanism and Predestination, Divining America, TeacherServe®, National Humanities Center.” Accessed October 12, 2023. http://nationalhumanitiescenter.org/tserve/eighteen/ekeyinfo/puritan.htm.

“Newcomb’s Paradox.” 2023. In Wikipedia. https://en.wikipedia.org/w/index.php?title=Newcomb's_paradox&oldid=1179359324.

Stearns, Raymond Phineas, and David Holmes Brawner. 1965. “New England Church ‘Relations’ and Continuity in Early Congregational History.” Proceedings of the American Antiquarian Society 75 (1): 13–45.

“Unconditional Election.” 2023. In Wikipedia. https://en.wikipedia.org/w/index.php?title=Unconditional_election&oldid=1150601094.