想起来renoir的一句话

You come to nature with your theories,and she knocks them all flat....

当然这是一个大课题，还有很多其他观点，如Poussin说到观察自然,there are two ways of seeing objects,one being simply to see them,and the other to consider them attentively.

显然理论和实际相符相承，又相互补充。