I wonder what "it" of "it is not that" indicates. "it" is in the last third line from the bottom. To the poet the world appears still more beautiful as he gazes at flowers that are doomed to wither, at springs that come to too speedy an end. The loveliness of May stirs him more deeply because he knows that it is fading even as he looks at it. It is not that the thought of universal mortality gives him pleasure, but that he hugs the pleasure more closely because he knows it cannot be his for long. --- I wonder what "it" of "it is not that" indicates. "it" is in the last third line from the bottom.