首楞嚴義疏注經 1.253

1.253

前問一食眾飽，今答軀命不同，反前問也。意顯心若離身即同他食，他食既非我飽，心知何關我身。身心相外，自他可例。

The earlier question was whether one eating sates the multitude; now the reply is that their physical lives are distinct, overturning the earlier question. The intention is to reveal that if the mind is separated from the body, it would be identical to another eating; since another's eating does not sate myself, how could the mind's knowing concern my body? The body and mind being external to each other can be compared to self and others.