The phenomena is roast duck. There are something in the dish, we cannot tell if we never opened because we have no experience in the open can (pure form of sensation). When we open the roast duck we have first experience can explain the roast duck taste, smell and color (pure form of understanding). We have the experience for the first time in the opening we can explain the roast duck in cans without opening a second time. No one knows the true noumena. The roast duck is caused by egg or otherwise but we don't know where it came from.