
In Kant’s framework, noumena represent the objective reality that exists independently of human perception. Here, the color of the faces, objectively the same, belongs to the noumenal realm. However, phenomena are the reality we experience, shaped by the mind’s interpretative filters. In Kitaoka’s illusion, our perception of luminance is skewed by the surrounding elements—lighting cues, shadow gradients, and contextual contrasts. These environmental factors trick our visual system, making the faces appear as opposites in brightness.
This illusion demonstrates how the mind imposes its structures and biases on raw sensory input, constructing a phenomenal reality that often diverges from the underlying noumenal truth.