Concerning your question about Donne, I assume you ask about his wanting the reader to go beyond the physical world because we, today, categorize him as a metaphysical poet. 

You should understand, though, that the word metaphysical here refers to the philosophy of knowledge and existence.  Donne's emphasis in his poetry is on human existence and our understanding of it.  He uses his stretched, extended metaphors (conceits) and unusual paradoxes, for the most part, toward an understanding of human existence.  Beyond that, his interest is in traditional Christianity.

Donne is certainly not akin to Romanticism, for instance, which emphasizes the transcendent, that which is beyond human understanding.  Donne wants understanding, and uses unusual methods to achieve it. 

Donne's poetry is highly artificial and intellectual and theological.  But if one interprets the term, metaphysical, as referring to something that is beyond the physical, the term is considered by many to be something of a misnomer:  a name that doesn't really fit.