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ExplainerMachine Ethics· Updated · 3 min read· in Culture

Engineers Use John Rawls's 1971 Veil of Ignorance to Program AI Fairness

A 1971 philosophical thought experiment by John Rawls has become a foundational blueprint for programming fairness into modern artificial intelligence systems.

By Joao Marques

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In short

  1. Artificial intelligence developers are increasingly using John Rawls's 'veil of ignorance' to design fair behavioral constraints for autonomous systems.
  2. The concept requires decision-makers to establish rules without knowing their own demographic identity, naturally incentivizing the protection of vulnerable groups.
  3. Techniques like Constitutional AI apply this by using a blinded 'AI judge' to enforce high-level principles during the reinforcement learning phase.

When engineers at major artificial intelligence labs sit down to write the behavioral constraints for their models, they are no longer just writing code. They are deciding whose values win when a machine has to make a choice, and they are doing so with global deployment on the line. To figure out what those rules should be, developers are increasingly reaching for a thought experiment published by political philosopher John Rawls in 1971.[1][2]

Rawls introduced the concept of the "original position," a hypothetical scenario designed to strip away human bias. He asked readers to imagine designing a society's rules from behind a "veil of ignorance"—a state where no one knows their own race, wealth, gender, or natural endowments.

If you do not know whether you will be born rich or poor, you are highly likely to design a system that protects the most vulnerable. As the Stanford Encyclopedia of Philosophy notes, this "occludes information, for instance, about principals' age, sex, religious beliefs," rendering the problem of choice determinate.[1]

How theoretical philosophy translates into a two-phase machine learning pipeline.

Historically, this remained a purely academic exercise. But the rise of autonomous systems has turned the veil of ignorance into a practical engineering requirement. When the Massachusetts Institute of Technology launched the "Moral Machine" experiment in January 2016, it collected human decisions on how self-driving cars should allocate risk during unavoidable crashes, testing respondents across more than 200 countries. The data revealed deep cultural biases, proving that crowdsourced morality is highly subjective.[3]

To prevent an artificial intelligence from simply memorizing and amplifying these demographic biases, researchers have pioneered a technique called "Constitutional AI" (CAI). As synthesized by the Factlen Editorial Team, the process operates in exactly two phases: Supervised Learning (SL-CAI) and Reinforcement Learning (RL-CAI). Instead of having human labelers grade every possible response, the developers write a constitution of high-level principles. The AI then grades its own outputs against that constitution.[5]

Researchers are attempting to quantify moral stability using a 0-to-1 scoring system.

Here, the veil of ignorance moves from theory to architecture. During the reinforcement learning phase, the AI judge evaluating the model's behavior operates completely blind to the identity of the user. It only knows the principles in its constitution. Models are evaluated on a Stability Score between 0 and 1 that aggregates exactly three core dimensions of welfare: productivity, survival, and conflict.[5]

The stakes for getting this right are immense. By September 2025, researchers at Harvard University were testing "Inverse Constitutional AI," a method that attempts to reverse-engineer a fair constitution from diverse human preferences using approval voting algorithms. The goal is to mathematically compress human values into a set of rules that a machine can follow, without letting the majority tyrannize the minority.[5]

The physical infrastructure where procedural fairness is encoded into neural networks.

Yet, this approach carries profound limitations. A machine operating behind a veil of ignorance is still executing a constitution written by a small group of developers. While some labs have experimented with crowdsourcing these rules through a project called "Collective Constitutional AI," critics point out that democratic input does not automatically resolve moral conflicts. Participatory approaches often overlook questions of enforceability, leaving the final arbitration to the engineers.[5]

The translation of political philosophy into neural networks represents a fundamental shift in how society regulates technology. We are no longer relying on Isaac Asimov's 1942 "Three Laws of Robotics," which imagined natural language rules for physical robots. Instead, we are encoding the procedural fairness of the original position directly into the weights of the model. The next time a language model refuses a prompt, the decision will be based on a mathematical approximation of justice.[2][5]

How we did this

Method
Comparing the theoretical constraints of John Rawls's original position against the practical training parameters of Constitutional AI and multi-agent reinforcement learning models.
What we found
While Rawls designed the veil as a thought experiment for human political consensus, AI researchers have inadvertently operationalized it as a literal training environment, using 'blinded' AI judges to enforce fairness without knowing which specific user or demographic they are interacting with.
What we worked from
  • Rawls's informational constraints (the veil): Occludes information about age, sex, and religious beliefs — Stanford Encyclopedia of Philosophy
  • Moral Machine demographic variables: Testing across over 200 countries — Wikipedia
Limits of this analysis
This analysis bridges political philosophy and machine learning, but cannot definitively prove that an AI trained this way achieves true Rawlsian justice, only that it mimics the procedural mechanics.

Terms to know

Original Position
A hypothetical scenario in political philosophy where individuals agree on the rules of society without knowing their own place within it.
Constitutional AI
An alignment technique that uses a written set of principles to guide an AI model's behavior during its training phase.
Reinforcement Learning
A machine learning process where a model learns to make decisions by receiving rewards or penalties based on its actions.
Trolley Problem
A classic ethical dilemma asking whether it is morally permissible to sacrifice one person to save a larger number of people.

Questions readers ask

What is the veil of ignorance?

It is a philosophical thought experiment created by John Rawls in 1971. It asks people to design the rules of society without knowing their own race, gender, or wealth, theorizing that this blindness leads to fairer rules.

What is Constitutional AI?

It is a training method where an AI model is given a 'constitution' of high-level principles. Instead of humans grading the AI's responses, a secondary AI judge evaluates the outputs against these principles to ensure safe behavior.

How does the Moral Machine relate to this?

The Moral Machine was an MIT experiment that crowdsourced human decisions on the Trolley Problem for self-driving cars. It highlighted the difficulty of programming ethics, as different cultures strongly disagreed on who should be saved in a crash.

Different angles

Procedural Ethicists

Argue that fairness in AI can only be achieved by blinding the system to demographic variables during training.

This camp, heavily influenced by Rawlsian philosophy, believes that the only way to build a truly fair artificial intelligence is to focus on the procedure rather than the outcome. They argue that if an AI model is trained behind a veil of ignorance—without knowing the specific identity, wealth, or status of the user it is interacting with—it will naturally default to principles that protect the most vulnerable. For these ethicists, the integrity of the training environment is more important than trying to manually hardcode answers to every possible moral dilemma.

Utilitarian Engineers

Focus on maximizing overall positive outcomes and minimizing harm, often relying on crowdsourced preference data.

Drawing on the tradition of John Stuart Mill, this perspective prioritizes the aggregate well-being of society. Utilitarian engineers argue that abstract philosophical principles are less useful than empirical data about what humans actually prefer. They favor large-scale projects like MIT's Moral Machine, which crowdsource ethical decisions to find the statistical consensus on harm reduction. From this viewpoint, an AI is aligned if its decisions produce the greatest good for the greatest number, even if the procedure to get there is messy or biased by majority rule.

Algorithmic Skeptics

Warn that mathematical approximations of justice still reflect the biases of the developers who write the rules.

Skeptics argue that the 'veil of ignorance' in AI is an illusion. They point out that even if an AI judge is blinded during the reinforcement learning phase, the constitution it enforces was still written by a small, demographically homogenous group of developers. This camp emphasizes that deciding what counts as 'harm' or 'helpfulness' is an inherently political act. They warn that wrapping these subjective decisions in the language of high philosophy or complex mathematics obscures the reality that corporate engineers are unilaterally setting the moral standards for global infrastructure.

Procedural Ethicists 40%Utilitarian Engineers 35%Algorithmic Skeptics 25%
Procedural Ethicists
Argue that fairness in AI can only be achieved by blinding the system to demographic variables during training.
Utilitarian Engineers
Focus on maximizing overall positive outcomes and minimizing harm, often relying on crowdsourced preference data.
Algorithmic Skeptics
Warn that mathematical approximations of justice still reflect the biases of the developers who write the rules.

Perspectives this story doesn't cover

  • Marginalized communities whose data is excluded from the training sets
  • Legal scholars debating liability for autonomous decisions

Sources

Source coverage

5 outlets

3 viewpoints surfaced

Procedural Ethicists 40%Utilitarian Engineers 35%Algorithmic Skeptics 25%
  1. [1]Stanford Encyclopedia of PhilosophyProcedural Ethicists

    Original Position

    Read on Stanford Encyclopedia of Philosophy →
  2. [2]Stanford Encyclopedia of PhilosophyProcedural Ethicists

    John Rawls

    Read on Stanford Encyclopedia of Philosophy →
  3. [3]WikipediaUtilitarian Engineers

    Moral Machine

    Read on Wikipedia →
  4. [4]WikipediaUtilitarian Engineers

    Trolley problem

    Read on Wikipedia →
  5. [5]Factlen Editorial TeamAlgorithmic Skeptics

    Synthesis by Factlen editorial team

    Read on Factlen Editorial Team →
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