Evolutionary theory of consciousness
Explanation
The evolutionary theory of consciousness encompasses various attempts to explain what adaptive function consciousness fulfilled and fulfils in organisms. If consciousness is ubiquitous and metabolically costly, it must have been selected for its advantages. Different authors have proposed candidates for that function: simulation of future scenarios, flexible integration of information, control in novel situations, intersubjective communication, capacity for complex learning. The question what is consciousness for? is one of the deepest and most controversial.
An influential version, developed by Nicholas Humphrey, is that consciousness arose to understand other minds. Living in complex groups demands predicting the behaviour of others. The most efficient way to do this is to develop an internal model of how a mind works, and the best way to have such a model is to be aware of one's own. Self-consciousness would then be a tool for social mentalisation: if I feel this way in this situation, he probably does too.
Another line, developed by Bernard Baars and Stanislas Dehaene from global workspace theory, holds that consciousness is the space where information is integrated to solve non-routine problems. Automatic processes solve the familiar; when something is new, ambiguous or critical, it is raised to consciousness to coordinate multiple specialised modules. Consciousness would then be the evolutionary solution to the problem of flexible information management in cognitively complex organisms.
Another perspective, defended by Antonio Damasio, connects consciousness with the bodily self and with homeostatic regulation. Basic consciousness would have evolved as a system that continuously monitors the organism's internal state, generating an ongoing sense of how things are going (internal map). This sense allows responding to internal and external perturbations flexibly, not only reflexively. Consciousness would then be, at root, a tool for homeostatic management extended to ever more complex levels.
Evolutionary theories also discuss when consciousness appeared. Some radical proposals (evolutionary panpsychism) place it in some basic form from the beginning of life. Others (Feinberg, Mallatt in The Ancient Origins of Consciousness) date it to the Cambrian, ~520 million years ago, with the appearance of centralised brains and complex sensory systems. Others limit it to vertebrates or mammals, depending on the neural or behavioural criteria required.
The criticisms are several. For some, functionalist explanations resolve access consciousness but not phenomenal consciousness (Chalmers's hard problem): we could imagine functional zombies without experience. For others, the evolutionary question is well-posed: if consciousness has a function, there must be an evolutionary explanation. The debate remains very open and connects with broader questions about the nature of consciousness, its distribution in the animal kingdom and the criteria for attributing it.
Strengths
- An evolutionary narrative coherent with the fossil record.
- Integrates palaeoanthropology, neuroscience and psychology.
- Explains continuity between species.
- Dialogue with theories of external memory and culture.
Main critiques
- Difficulty of empirical verification of the deep past.
- Risk of just-so narratives.
- Does not directly address the hard problem.