Growing Confidence and Remaining Uncertainty About Animal Consciousness

While the study of consciousness has had a controversial history and, until recently, a pessimistic prognosis, recent views within the neuroscientific community suggest that a maturing if incomplete scientific understanding of consciousness is close at hand. The purpose of this essay is to specify the major points on which in my opinion there is widespread though not universal agreement, as proposed benchmarks for the current state of consciousness research across the phylogenetic spectrum. Most published definitions of consciousness boil down to a focus on it as a process arising in a nervous system engaged with a body and its environment, giving rise to subjective (personal) experience. A broad consensus on the phenomenology of consciousness sees it consisting at a minimum of (1) awareness_ ₐnd focused attention, (2) unity of perception, (3) qualitative variations in content, (4) mental causation, and (5) a sense of self. There is also broad agreement that the substrate of consciousness requires sizeable, complex nervous systems organized into several hierarchical levels of processing. Further insight is gained by reconstructing the evolution of subjective phenomenological experience ― most likely from multiple origins, hosted by a diversity of body and brain architectures, and diverging into markedly different forms across the animal kingdom. However, three major mysteries about phenomenological experience that remain unresolved are (1) the neurological correlates of consciousness, (2) the apparent gap between phenomenology and mechanism, and (3) the process that monitors the brain activity admitted into consciousness.