What is the hard problem of consciousness?

The hard problem of consciousness is the problem of explaining why and how physical systems such as brains give rise to subjective experience. According to the Internet Encyclopedia of Philosophy, it asks why there is something it is like for a subject when certain physical states occur, rather than those states being nonconscious. The philosopher David Chalmers named it in 1995. [1] [2]

Chalmers separates consciousness into easy and hard problems. The easy problems are those open to the standard methods of cognitive science, where a phenomenon is explained by computational or neural mechanisms. His examples include discriminating and reacting to stimuli, a system's access to its own internal states, the focus of attention, the deliberate control of behavior, and the difference between wakefulness and sleep. In his text, these are called easy because they concern cognitive functions, and explaining a function requires only specifying a mechanism that performs it. [3]

The hard problem is the problem of experience: the felt quality of redness, the sound of a clarinet, pain, emotion. Chalmers argues it persists even after every relevant function is explained, because one can still ask why that processing is accompanied by experience rather than going on in the dark. The ABC News summary of his view puts it as how the machinery of neurons and synapses can produce the colours we see or the sounds we hear. [3] [4]

The Internet Encyclopedia of Philosophy says science usually explains what a thing does, how it changes over time, and how it is put together. Yet even a complete account of these features of the conscious mind leaves open the question of why it is conscious. Part of the argument is that we can seem to conceive of creatures physically and functionally just like us that lack consciousness, which suggests a purely physical explanation leaves something out. This is often described as an explanatory gap, a term coined by Joseph Levine in his 1983 paper. [1] [3]

Chalmers contrasts this with genes or life. Once you explain how DNA stores and transmits hereditary information, asking how it is a gene is a conceptual mistake, since being a gene just means performing that function. Asking how information processing is experienced, he says, is a legitimate further question. He notes that it is widely agreed experience arises from a physical basis, but there is no good explanation of why and how. [3]

Chalmers concludes that the usual explanatory methods of cognitive science and neuroscience are not enough and that a new approach is needed. He does not say experience lacks a function; it may play a cognitive role, but explaining a role would not automatically explain experience. The Internet Encyclopedia of Philosophy states the stakes more broadly: the problem either calls for explanation beyond the usual methods of science or marks the limits of what science can explain. The Stanford Encyclopedia of Philosophy likewise describes the concern as empirical explanations being structural or functional while phenomenal consciousness is not reducible to them. The search results given here do not cover the responses of critics who reject the problem's framing. [3] [1] [5]