The "Falsifiability" Cargo Cult
>it's basically an unfalsifiable theory, i.e. religious belief.
If we treat falsifiability as a rigid, mechanical rule, we fall into a kind of cargo cult science: we imitate the outward form of scientific rigor (asking “is it falsifiable?”) without acknowledging the deep logical and computational limits beneath it.
1. Falsifiability in science
Karl Popper’s falsifiability principle says:
A theory is scientific only if it can, in principle, be proven false by some conceivable observation or test.
That relies on the idea that for any statement we care about, we can decide whether the evidence rules it out or not.
2. The Halting Problem’s obstacle
The halting problem proves that there is no general algorithm that can decide, for every program and input, whether it halts.
- If a “scientific theory” were formalized as a program that generates predictions, then testing falsifiability would mean checking whether the program ever produces a contradictory prediction.
- But the halting problem shows we cannot, in general, determine if that contradiction will eventually appear or if the system will just keep running forever without resolving.
- So falsifiability becomesundecidable in full generality: you can’t always know whether a theory is testable against experience.
3. Incompleteness theorem’s obstacle
Gödel’s incompleteness theorem shows that in any sufficiently powerful formal system:
- There are true statements that cannot be proven within the system.
- If a scientific theory is formalized mathematically, some consequences of it may be undecidable within the theory’s own framework.
That means:
- Even if a counterexample to the theory exists in reality, the system may not be able to prove that the counterexample is a contradiction.
- So some theories cannot be fully falsified by logic alone — the tools to demonstrate inconsistency are inherently limited.
4. Why both together matter
- Halting problem: blocks the computational side — we cannot always tell whether a testable contradiction will ever arise.
- Incompleteness theorem: blocks the logical side — even if a contradiction exists, we might never be able to prove it.
Thus, the method of falsifiability, while powerful in practice, cannot serve as an absolute, universal criterion. In principle, there exist theories or systems of rules that are either:
- Undecidable (we can’t tell if they’ll ever fail), or
- Incomplete (failures exist but cannot be demonstrated within the system).
This undermines the dream of a fully mechanical or formal way of demarcating “scientific” theories by falsifiability.