Asked by: Alice Parker, by email

It’s still a mystery. We understand a lot (and more all the time) about how the brain’s sensory and memory systems work, and how its frontal lobes plan actions and make decisions. But there’s a vast gap (called the ‘explanatory gap’) between this scientific knowledge and our understanding of subjectivity – how it feels to be me.

The so-called ‘hard problem’ of consciousness is how to relate objective processes in the physical brain to a person’s subjective experiences, such as seeing green or tasting a banana. Some scientists think we need a new theory, perhaps based on quantum physics or alternate realities. Others say that once we fully understand the ‘simple’ things like memory, there’ll be nothing else to discover as consciousness is not a separate entity.

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