In this post, we explore the path to intelligent truth by meandering through an abstract logical village. We show that A.I. is incapable of true intelligence as identifying the rules and base truths of an argument are beyond computation. This leads to a clarification of why A.I. hallucinates, why agents need human intervention, and ultimately why modern computers may never be able to reach AGI.
The abilities of a computer are constrained by constructive logic. This type of logic acts to derive conclusions through step-by-step derivation of proof. The Curry-Howard correspondence shows there is a direct equivalence between constructive logic and computation. However, constructive logic does not cover all possible provable objects. Axioms come under classical logic, and are self-evident truths that cannot be proved by construction.
The Analogue
Let’s explore this, by first visualising it. Imagine that propositions are represented by houses in a village. Each house is painted blue if it is a true proposition, and red if it is not. In classical logic, this is all you have; truth and falsity are simply asserted. To expand into constructive logic, we connect the houses by a series of one way roads, that allow you to travel from one to the other. These roads are the constructed proof; you start at one house (proposition), and move your argument on using a set of rules (logic) until you reach your conclusion. The computer is essentially only able to move from house to house via the roads; realising the colour of the house when it arrives by a road.
In the analogy, a topos is akin to a village; a series of houses connected by roads. It is a self-contained geometric landscape following it’s own internal logic. However, in some way the road network and colour and placement of houses is abstract. The combination can be applicable to many ideas, not just the starting proposition. Ideas that are similar structural, or connect with similarly structured rules and can be interposed with each other. This is the nature of a topos, and abstraction that defines structure between propositions on a meta level.
The Computer
Now, there are some problems here. How does a computer know at which house to start ? We know that a computer proceeds through constructive logic. It can only know where to go, by starting at one house, travelling on a road, and arriving at another.
The houses that have no roads leading to them as self-evident truths, or axioms. These are truths, or falsehoods that are asserted by classical logic. A computer cannot determine these, as it can only live in the realm of constructed logic. It can only follow roads, not jump to a house.
In constructive logic, there is hope that axioms are not truly houses with no roads leading to them; but that the roads are yet undiscovered. This is an open question, and there is no such proof of existence; and we know from Godel’s Incompleteness theorem that there are pockets of truth that no road can ever reach.
The Human
This leads to point where humans enter in. The starting houses, and the roads define the logical universe in which the village exists. We know the computer can use the roads, and discover them through training. It does this through taking small steps through the village, mimicking maps already laid out by humans. But we know that the A.I. must be prompted to act, a human must define the starting house, and more essentially, select the village to start in. This is an essential part of intelligence.
This is selecting the topos; picking the logical universe in which the proof exists, and what it can be constructed from. We know this is outside of constructed logic, and must be non-computable by definition.
The process of training the machine is discovering a set of pre-computed roads by which the computer can travel. Again, the topos is interchangeable, the houses may represent analogous propositions connected by the same road network. So, a computer can adapt, it can use what it has learnt from one set, and apply that to a different village; but this leads to problems.
The Hallucination
If we now swap out the propositions of the houses, and the road map is not identical, then the computer will arrive at houses that don’t exist, or produce contradictions. The road map still connects them, but the output is nonsensical; this is hallucination.
It is an artefact of knowing the connections between propositions, but not the topos itself. The two are intimately connected; the houses, and the roads. It can be improved by further training, crawling through more and more villages, but will lead to failure, as it is just tunnel vision in a intricate landscape.
The Agent
We can now see why A.I. finds it difficult to be truly agentic; why it relies on constant feedback from humans. The human must constantly reset the point that the agent is starting at, in different villages. The human must help the agent backtrack from dead ends. They can be constantly frame constraints, don’t follow that road. This is because the computer cannot see further than the point it is at, and the road it is on. It gets lost, it doesn’t know where to start. We have made some progress in automating this through frameworks, but it is still a perennial problem.
The AGI
This means ultimately a human must always be in the loop. The act of identifying and selecting the topos is inherently non-computational. It is based on identifying axioms that define it, which cannot be discovered constructively. A.I. can approximate this process, but ultimately will find situations where it will fail. We know that non-constructive logic is non-computational, and so this is a problem that cannot be physically overcome by computers. This pours cold water on the potential of computers to achieve AGI.




