心不在焉,视而不见,听而不闻,食而不知其味。
When the mind is absent, one looks without seeing, hears without listening, and eats without knowing the taste.
Plain meaningWithout attention, you can be present and still miss everything.
Original context and translation note
English wording on Gu Ren Said is an original reading aid, not a claim that there is only one valid literary translation.