Philosophy
Phenomenal Concepts and the Explanatory Gap of Consciousness
Quick fact
The term 'explanatory gap' was coined by philosopher Joseph Levine in 1983, and it captures the idea that even complete knowledge of brain processes might never explain why they feel the way they do.
Why this is interesting
You know what it feels like to taste chocolate, but how could you ever explain that exact feeling to someone who has never had it? Why is the 'what it's like' of experience so hard to capture in physical terms?
Read the full explanation
Understanding Phenomenal Concepts and the Explanatory Gap of Consciousness
Think of your mind as having two kinds of ideas: you can think about a red rose by its physical properties (light wavelengths, etc.) and by its subjective feel (the redness you experience). The latter is a phenomenal concept—it's how you think about what an experience feels like from the inside. Now, imagine a neuroscientist who knows every detail about how your brain processes a red rose, but has never seen red. They have all the physical facts, but they still don't know what red looks like. That gap—the difference between knowing all the physical facts and knowing the feeling—is the explanatory gap.
A deeper explanation
The explanatory gap arises because physical explanations are about objective, third-person facts, while phenomenal concepts refer to subjective, first-person experiences. When we use phenomenal concepts, we're not just describing neural activity; we're pointing to what it's like to have that experience. The gap is the apparent failure of physical facts to logically entail phenomenal facts. This challenges physicalism, the view that everything is physical, because it suggests that even a complete physical description of the brain might not account for the subjective feel. Some philosophers argue that the gap is epistemic (a limitation of our understanding), while others see it as metaphysical (indicating consciousness is non-physical). This problem is central to the 'hard problem of consciousness' and motivates research into how consciousness arises from matter.