The hard problem of consciousness is not a just little local difficulty that will be solved by advances in neuroscience. As Thomas Nagel said, ‘it invades our understanding of the entire cosmos and its history’. 

It was David Chalmers who first proposed a distinction between ‘hard’ and ‘easy’ problems of consciousness – a distinction which has been problematic ever since. It gives too much ground to those who believe neural and computational science explain consciousness key aspects of consciousness. And it is biased towards the perspective that there are parts of the mind that entirely belong to the physical world and are no more than physical way stations in the causal chain between sensory inputs and behavioural outputs.

Contrary to Chalmers, the hard problems of consciousness,  that will always resist understanding through objective quantitative investigations, go beyond subjective experience and ‘what it is like’ to be a conscious subject. They encompass  aspects of the mind that Chalmers categorises as ‘easy’.  These include:  our ability to describe our mental states, to focus our attention or deliberately to control our behaviour, and to acquire and integrate information; the difference between wakefulness and sleep; the degrees and content of consciousness. Moreover agency, selfhood, intelligence, and our relationship to time are also ‘hard’ in Chalmers’ sense.