Philosopher David Chalmers distinguishes between 'easy problems' of consciousness, which relate to cognitive functions, and the 'hard problem,' which asks how physical processes give rise to subjective experience (qualia).

Chalmers' distinction is crucial for understanding the current impasse in consciousness research. The 'easy problems' include explaining phenomena like wakefulness, attention, learning, memory, and the ability to report mental states. These are functionally defined and, while complex, seem amenable to conventional scientific investigation through neuroscience and cognitive psychology. However, the 'hard problem' is qualitatively different. It's the question of *why* and *how* any physical process should give rise to subjective, inner experience – the 'what it's like' aspect of consciousness. Why isn't a brain just an elaborate machine processing information without any inner feeling? This problem highlights the explanatory gap between objective physical descriptions and subjective phenomenal experience, challenging purely materialist explanations and prompting diverse philosophical and scientific responses.