When Fancy then with her black train appears,
Of difficulties, dangers, hardships, fears,
With a pale ghastly face, whole awful frown
Frights sleep away, and hardens beds of down,
Be ready to say thus: 'That which I see,
'Is not indeed that which it seems to be.'
Then strait examine it, and try it by
Those rules thou hast, but thus especially,
Whether it points at things in us or no;
If not at things which in our pow'r we know'
'Tis but a bug-bear dream, an empty show;
Of no concern to thee, like clouds that fly
In various forms, and vanish in the sky.