首楞嚴義疏注經 2.185

2.185

隔紙膜不見外物，隔皮膚不見五藏，豈同前聖真見之用？斯則真見妄見前後五重，條然可辨。而云云何得知是我真往，胡不察焉？

Obstructed by a sheet of paper or a membrane, they do not see external objects; obstructed by skin, they do not see the five viscera. How could this be identical to the function of the true seeing of the aforementioned sages? Thus, true seeing and false seeing form five successive tiers, clearly distinguishable. Yet he said: 'how can I know that it is my true [nature]?' Why did he not examine this?