In the octopus case, the fine-tuning is greater—it’s more than just fine-tuning—and it does not only happen quickly. The octopus might watch some of the arm’s wandering as if it is a spectator. In us, these adjustments are too fast to see. In the case of humans, these rapid adjustments of the arm come from the brain, and they are visually guided. In the octopus, the motions are guided by the arm’s own chemical and tactile senses, not by vision
