For the poet, being alone is a condition conducive to:

Explanation

'How strange we grow when we're alone.'

Note: Passage I is Siegfried Sassoon's 'Alone' ('When I'm alone…'), which is copyrighted in many countries and not reproduced. A man's casual 'When I'm alone' sets the speaker thinking how 'strange we grow when we're alone', unlike the selves that meet and talk and say good-night. 'Alone' is the stillness where our spirits walk, 'life endured and known', which leaves only our inmost faith.