Why do we not perceive photons?
D005556:Form Perception / Q000502:physiology; D006801:Humans; D008027:Light; D009039:Motion Perception / Q000502:physiology; D012160:Retina / Q000502:physiology*; D014785:Vision, Ocular / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*