Nature that framed us of four elements,

Warring within our breasts for regiment,

Doth teach us all to have aspiring minds:

Our souls, whose faculties can comprehend

The wondrous Architecture of the world:

And measure every wandering planet's course,

Still climbing after knowledge infinite....

 

Christopher Marlowe, Conquests of Tamburlaine

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So many worlds, so much to do,

So little done, such things to be.

 

Alfred, Lord Tennyson, In Memoriam