When Socrates was sentenced to death by the Athenian people, Plato went through a personalcrisis. How could the city of Athena, the center of knowledge and wisdom of the known world,sentence their wisest man to death? Is democracy really just? Or rather, is it just a form of mobrule? Plato’s doubts culminated into a critique of direct democracy. The same set of criticismwas later used to create representative democracy and authoritarianism.

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For Plato, only a rational man who puts reasoning above sentiments and desires is fit to rule.This “Philosopher King” should possess all the necessary skills and wisdom to run a country.Similarly, the pursuit of universal truth should be done by capable men, who can utilize logicand reasoning in the studies. Like the “Philosopher King”, these philosophers must be rationalto qualify for the journey towards truth. From this set of reasoning, the notion of “rationalism” isborn.

“Rationalism” is the epistemological theory that runs opposite of empiricism. The latter viewedthe world as the products of objective truths. For instance, a rock will be on Earth regardless ofhuman observation. The pursuit of universal truth is to understand these objective measures.Rationalism denies the existence of objective truth, believing that the rock’s existence ismeaningless if it’s not observed by conscious minds. Since the initial observation will be asubjective one, the subsequent interpretation of the rock would only be subjective. Yes, whenmultiple individuals combined their observation and understanding, the observation andinterpretation of the rock will seem objective. But studies of this rock never escaped the realmof personal knowledge.

And if everything is personal knowledge, it’s necessary to refine the production of personalknowledge. For rationalists, the pursuit for universal truth is but the pursuit for a rational mind.Rather than seeking that supposed objective truth, one should refine their mind so that theycan make the best judgement on each matter. To become rational, then, is to refine one’sreasoning to interpret the world better and to construct viable strategies.

So, it begs the question: how should a rational mind think? Yudkowsky’s credence algorithmseeks to answer that question. Imagine a scale: the middle is marked with the number (1). Oneincrement to the left marks the number (1/2). And for each one increment going towards theleft, the number is modified by a factor of (1/2). As for the one increment towards the right ofnumber (1), it marks the number (2). And for each increment going towards the right, thenumber is scaled by a factor of (2).

To visualize, the scale looks like this.   {...... 1/16, 1/8, 1/4, 1/2, 1, 2, 4, 8, 16, .......}

To use this scale, one simply propose a question, and put the two extreme responses to thequestion on either side of the scale respectively. One would then start on the position of (1)before pushing their position on the scale around as evidences appear.

For instance, a person named Mark is choosing between doctor and lawyer track in college.On the left side of the scale lies the proposition to become a doctor, and on the other side,lawyer. Mark starts at position (1) before examining his evidence.

He likes helping people, one score for doctor! (1/2) Then he found out that he was good atdebate, one score for lawyer! (1) He likes mock trials. (2) However, he doesn’t want to defendguilty people in court. (1) Wait, he gets to choose his client, so he doesn’t have to deal withthat. (2) He prefers suit over lab coats. (4) He failed high school biology (8). At the end, thescale favors lawyer over doctor. As such, the rational choice for Mark is to choose the lawyerpath.

It should be noted that Yudkowsky was heavily influenced by Bayes’ theorem, which alsosought to quantify evidence and confidence on a scale. Regardless of the source of inspiration,Plato, Bayes, and Yudkowsky sought to remove human error when a decision is made. ForPlato, the Philosopher Kings cannot lead reasoning; rather, they should be led by reasoning.Yet, both Plato and Socrates doubted the plausibility of this notion as the human brain willinevitably bring feelings into things. After all, when reasoning is done, what is there to judge thereasoning?

Yudkowsky and Bayes answered that question with mathematics, illustrating that it’s possibleto conduct reasoning independently from human feelings. It’s reasonably to assume that Platowould rejoice at the independence of reasoning as a Form from human reasoning.

On the other hand, removing reasoning from feeling can seem cold for the compassionate.Indeed, Bayes’ theorem demonstrates that by moving at factors of (2), which means everypush makes a certain option twice as likely. Any movement is treated as overwhelmingevidence for and against a certain motion. These unforgiving odds left no room for compromiseon the scale, a great limitation when dealing with messy real-world problems.

To put it bluntly, don’t implement this method when you are fighting with your friends or lovedones. - Plautus 

Written by: Plautus