Constitutional AI's method: principles, critique, and revision
Constitutional AI (2022) trains a harmless assistant from a short written list of principles instead of thousands of human harm judgments. This theme covers the mechanics of how that substitution actually works: a model critiques its own harmful response against a sampled principle, then revises the response to remove what it identified, and the result becomes the model that seeds everything downstream.
The critique-and-revision pipeline unfolds step by step, closing with the direct-revision ablation, which tests whether the critique step was ever necessary in the first place.
Constitutional AI trains a harmless assistant using only a small set of written principles as the source of human guidance, rather than human harmfulness labels, and this theme covers the mechanics of that method's supervised stage. The constitution is the set of natural-language principles steering the whole pipeline, split in practice into two specific lists: the 16 critique/revision instruction pairs used in the supervised stage, and a separate 16 multiple-choice comparison principles used later by the feedback model. Critique and revision is the pipeline itself, a model critiques its own harmful response according to a sampled principle, then revises the response to remove the identified harm, producing SL-CAI, the fine-tuned model that results and that seeds the later RL stage. Hand-written few-shot examples prevent the model from confusing the critique and revision roles it must switch between. Principle ensembling, sampling a different principle per comparison rather than reusing one throughout, and the direct-revision ablation, which tests whether the critique step is even necessary, both validate specific design choices within this pipeline rather than proposing new ones.