There are no known differences in brain mechanisms of consciousness between humans and other mammals

Recent scientific findings indicate that consciousness is a fundamental bio logical adaptation. The known brain correlates of consciousness appear to b e phylogenetically ancient, going back at least to early mammals. In all ma mmals, alertness and sensory consciousness are required for the goal-direct ed behaviours that make species survival and reproduction possible. In all mammals, the anatomy, neurochemistry and electrical activity of the brain i n alert states show striking similarities. After more than seven decades of cumulative discoveries about waking and se nsory consciousness, we have not yet found any fundamental differences betw een humans and other mammals. Species differences such as the size of neoco rtex seem to be irrelevant to the existence of alertness and sensory consci ousness, though different mammals obviously specialize in different kinds o f sensory, cognitive and motor abilities. Sceptics sometimes claim that objective evidence for consciousness tells us little about subjective experience, such as the experience of conscious pa in. Scientifically, however, plausible inferences are routinely based on re liable and consistent patterns of evidence, rn other humans, we invariably infer subjective experiences from objective behavioural and brain evidence - if someone yells 'Ouch!' after striking a finger with a hammer, we infer that they feel pain. The brain and behavioural evidence for subjective cons ciousness is essentially identical in humans and other mammals. On the weig ht of the objective evidence therefore, subjective experience would seem to be equally plausible in all species with human-like brains and behaviour. Either we deny this experience to other humans (which is rarely done) or, t o be consistent, we must also attribute it to other species that meet the s ame objective standards. It seems that the burden of proof for the absence of subjectivity in mammals should be placed on the sceptics.