Meet Mary. She was born without the ability to see or experience color at all. Jealous at her peers who could see color, she set out to learn everything there is to know about color sight. The physics of light, wavelengths, photons, refraction, reflection, you name it. The biology of how the eyes and brain process color, and all the associated neuroscience. Every last bit involved in the process of seeing colors, she learned. She became the world leading expert on color sight, and possessed complete scientific knowledge of the topic. There wasn't anything to study about the subject that she hadn't learned.

One day, a medical breakthrough was made. Mary had surgery, and received color sight for the first time in here life. When she woke up from surgery, her father greeted her with a red rose. For the first time in her life, she experienced the vivid sensation of redness. The crucial question is, did Mary learn anything new when she saw the red rose?

If she learned what it is actually like to experience the color red, then this suggests that there is more to consciousness than all the physical facts combined. The subjective quality of experience, known as qualia, appears to be something more than just what is described by physical information.