Intelligence & The Ladder Of Causation
If intelligence is defined as the ability to acquire and apply information, then an important question becomes: application to what? If information is to be applied, it must be in support of some objective. An intelligent agent applies knowledge for the purpose of causing some desired outcome. The cognitive model that informs its actions can therefore be considered to be a causal model.
In The Book of Why, Judea Pearl introduces the concept of the ladder of causation that describes three levels of cognitive ability that are needed in order to fully understand causality. The three levels are association, intervention and counterfactuals.
The first level, association, consists of observing and detecting patterns of correlation between the elements in a system. At this level, one can recognize that the sunrise coincides with the crowing of the rooster, but it can not be determined which of these phenomena caused the other, or indeed whether a third event caused them both. Most of modern statistics, AI and big data rely largely on correlation and are therefore not able to directly identify causal relationships.
The second level, intervention, permits establishing causality between particular variables in a system by performing empirical experiments. If B happens every time I do A, then I have established that A causes B.
The third level, counterfactuals, permits the inference of causality based only on a causal model. Counterfactuals are like thought experiments in which a causal model is used to determine what would happen, if particular interventions to a system were to be performed, or what would have happened had some variables been different. This level allows us to successfully ‘predict’ counterfactual realities, provided that a sufficiently representative causal model has been established.
There is a direct relationship between Pearl’s ladder of causation and the concept of gene-level and organism-level cognition which I discussed in my previous article titled “All Life Is Intelligent”.
What I coined gene-level cognition is a form of intelligence, defined as “the ability to acquire and apply information”, that is produced entirely by evolutionary processes which are a priori to the organisms that possess it. In other words, while an organism with gene-level cognition can acquire and apply information, it does so based on established causal relationships which have, in effect, been encoded in its genes. The establishment of the causal relationships that determine its behaviour take place in advance, during the evolutionary process that leads to its particular configuration. Gene-level cognition drives purely instinctual or reflexive behaviours. In relation to Judea Pearl’s ladder of causation, gene-level cognition falls squarely into the second level: intervention. That is, evolution establishes causation by performing empirical experiments in the form of random mutations and selective pressures within an organism’s ancestral environment.
Organism-level cognitive models are formed, as the name suggests, within the organism. When an organism learns through imitation or experience, it is creating an organism-level causal model. Brains evolved to provide organisms with organism-level cognitive modelling abilities. Once an organism has developed a causal cognitive model, it can deal with novel circumstances to the extent that its learned model is applicable. In terms of Pearl’s ladder of causation, learned cognitive models permit the use of counterfactual thought experiments to drive behaviour.