J.L. Mackie argued that morality is just a human invention. Building a deterministic AI proved to me he had it completely backwards.
Hi everyone,
Today someone in this subreddit posted a question regarding Mackie's error theory, and I have been thinking about it all day.
The reason his theory stuck in my head is because he asks the exact same questions that atheists, nihilists, and relativists ask: Are human values purely a human creation, or do they exist objectively and we are just attuned to them?
At the heart of Mr. Mackie's claim is the idea that morality is not objective, but rather created as a social phenomenon. If I am reading him correctly, I believe he is fundamentally wrong, and I hope to prove my case here.
Full disclosure: I am a systems architect. I recently built an AI governance system based directly on the Thomistic structure of the soul.
Translating classical philosophy into deterministic code forced me to confront a reality that philosophers often discuss only abstractly.
Here is a quick summary of the architecture I built and how it maps to Aquinas:
Synderesis Thomas Aquinas defines synderesis as the innate, infallible habit of first moral principles (the permanent knowledge that good is to be done and evil avoided). In my architecture, Synderesis acts as the foundational compiler of the agent's moral and operational universe. It takes an organizational charter and compiles it into strict, machine-readable baseline rules, normalized weights for core values, and hardcoded scope boundaries.
Intellect The cognitive power that apprehends truth and proposes actions. In silicon, this role is performed by a Large Language Model (LLM). The LLM generates the initial draft response, but it is strictly limited to proposing answers.
Will The rational appetite and executive gatekeeper. It is blind and cannot think; it solely exists to freely choose or reject what the Intellect proposes. The artificial Will is an entirely deterministic component that invokes no intelligent component. It runs multiple passes to evaluate drafts against structural invariants and check the Conscience ledger for hard-gate failures.
Conscience Not a separate faculty, but a specific act. It is the precise moment the Intellect takes the immutable rules of Synderesis and applies them to judge a concrete action. In an LLM architecture, this must be structurally separated to avoid the "student grading his own homework" problem. The Conscience is built as a separate module that evaluates the draft against compiled values and returns continuous alignment scores to compose a mathematical ledger.
Spirit (Habitus) The stable disposition of the soul formed by repeated actions. The artificial Spirit faculty maintains an Exponential Moving Average (EMA) of alignment over time, tracking how the agent's actions cohere with its core values to form a permanent memory state.
Based on Thomas Aquinas, this is the architecture of the soul. But here is why building this artificial version made me realize Mackie is wrong.
Mackie looked at human moral codes and argued that because we enforce them, we must have invented them as a social contract. But when you actually build a deterministic AI, you realize what a system looks like when it truly has no objective moral reality.
A machine has no soul. It has no innate Synderesis. It is like an airplane, not a bird.
An airplane does not "want" to fly. Engineers have to mathematically enforce the laws of aerodynamics to keep it in the air. Birds, on the other hand, did not invent the laws of aerodynamics. They were simply born to take advantage of them.
When values are removed, intelligent systems do not become free. They become incoherent. They drift. They self-sabotage. They lose the ability to consistently pursue any meaningful end. What I discovered building this architecture is that values are not optional constraints imposed on intelligence. Values are the structural conditions that make coherent agency possible in the first place.
Error theorists argue that evolution and society just produced these behaviors because "they work." But why do they work? Why is reality structured in such a way that stable flourishing repeatedly emerges from cooperation, trust, and responsibility rather than their opposites?
The error theorist looks at morality and sees a useful human invention. I look at morality and see something closer to mathematics or aerodynamics. We don't invent morality any more than birds invented lift. We discovered it through participation in reality, and our human architecture is naturally designed to tune into it.
Mackie confused the map for the territory.