Yet you can measure the wavelength or combination of wavelengths of light nearly everyone agrees is, say, green, and legitimately call that wavelength the cause of the experience of green. No, that does not give you every intermediate step between your retina and your experience of green, but pointing that out is like my creationist brother-in-law pointing out that there is no intermediate for between, say, ancient land animals and whales, and then when I point to, say, dorudon, insist that I provide an intermediate step between dorudon and whales. He will never be satisfied.