Brooks\'s hypothesis

Brooks's hypothesis is the claim, articulated by Rodney Brooks in his influential 1991 paper "Intelligence Without Representation," that intelligent behavior can be generated by machines that do not maintain internal world-models, symbolic representations, or explicit plans. The hypothesis is the philosophical foundation of behavior-based robotics and reactive systems, and it stands in direct opposition to the classical AI paradigm that treated representation as a prerequisite for intelligence.

The hypothesis is stronger than the empirical claim that some behaviors do not require representation. It is the theoretical claim that representation is not merely unnecessary for some tasks but is unnecessary for the foundation of intelligence itself. Brooks argued that the world is its own best model, and that a robot that continuously interacts with its environment does not need to reconstruct the environment internally because the environment is always available for direct perception.

The hypothesis has been both influential and controversial. Its defenders point to the success of behavior-based robots in real-world navigation and the parallel insights from embodied cognition and affordance theory. Its critics argue that while reactive behavior may suffice for simple tasks, complex tasks — planning, language, abstract reasoning — demonstrably require representation, and that Brooks's hypothesis cannot be extended to explain these capacities without collapsing into triviality.

The deeper systems-theoretic question is whether Brooks's hypothesis is a claim about engineering or a claim about nature. If it is an engineering claim — that some useful robots do not need representations — it is uncontroversially true. If it is a claim about natural intelligence — that human cognition does not involve representation — it faces formidable counter-evidence from cognitive psychology and neuroscience. The ambiguity has allowed the hypothesis to survive decades of debate by shifting between these two readings.