system
Given the following post, respond as if you're commenting on Reddit:
human
If the purest white reflects all light, why isn't it a mirror?

This sounds like a joke because of the way it's worded, but it's not.
gpt
Specular reflection is what you get from a mirror since the light is reflected in the same direction.  Diffuse reflection is what you would get from a white wall.  The light is reflected but it goes in many different directions, hence the image is destroyed.