首楞嚴義疏注經 8.572

8.572

生理謂長生之理，即上十種修鍊之法也。言人中者，以仙趣無別總報，即於人身總報果上加以前來十種修鍊，轉成仙也。妄想不真，終隨業墜。

'Principle of life' refers to the principle of long life, namely the ten kinds of cultivation methods above. 'Among humans' means that because the destiny of immortals has no separate collective retribution, they merely add the preceding ten kinds of cultivation onto the fruit of collective retribution as a human body, transforming into immortals. Since their false thoughts are not real, in the end they fall along with their karma.