I have a theory: I think sentience might be a necessary outcome of animacy, and sapience a result of sociality. An animal who ventures out into the world must be able to make sense of a complex environment, which a sessile being can safely ignore until something bumps into it. The mobile creature must be able to filter through a barrage of information in order to pick out what’s relevant for its life, both now and in the foreseeable future. It must have heuristics to navigate the world and survive and multiply in it, which basically boils down to having emotions — those desires that tend to lead to optimal health and fecundity — and intentions — what must be done to satisfy those desires. Perception of pain and pleasure, and a basic understanding of the self as the source of movement and feeling and different from external things, seem to be fundamental to being mobile. Plants and fungi and algae and mollusks can get away with an entirely more simple set of inputs and outputs, since they let the world come to them.

Modeling the world is complex, indeed, but even more complex is the task of modeling other intentional beings. This is exactly what social creatures need to do in order to predict and interpret the actions of fellow sentient beings. Empathy, play, learning, coordination, and communication are all parts of the necessary toolset. Brain size is in fact correlated with sociality, and the pre-fontal cortex that grants us our awesome human abilities gets bigger in direct proportion to a species’ group size. Crows and chimps, for example, about the same brain-to-body ratio, which is much bigger than their less social relations and gives them to power to solve problems and impress scientists with their mental prowess. Selfhood also changes meaning for social animals, I believe, so that they understand themselves to be an individual within the group, with a personality and relationships to keep track of. It seems reasonable to suppose that they can mentally model themselves as well as they can model others, giving themselves not just a sentient interiority, but an awareness of that interiority — a rudimentary self-consciousness.

We treat self-consciousness and social-awareness as almost magical abilities that small children and animals only appear to possess due to slight of hand and misunderstanding. But I think sentience and sapience are the results of quite useful abstractions, which are surely much easier than trying to predict the chaotic behaviors of rocks moving past you and four-legged fuzz balls based on colors, smells, and movements that mean nothing and evoke no emotion. Much easier, once the refactoring happens, to categorically identify food, foe, and friend and feel attachments and revulsions, joy and fear, puzzlement when the world cannot be reconciled and satisfaction when everything makes sense again.

This theory is only half-baked, and it’s probably too generous in some areas while elsewhere being too limited in scope. Think on it with me!