What does it mean to have "A marriage between the natural and the supernatural"?

A marriage between something and something is an idiomatic
expression derived from the idea of a marriage between two adults, traditionally, a
husband and wife, which indicates that two individual, disparate, separate entities
(i.e., people) have been joined together in an alliance or bond. This applies to the
expression, "A marriage between the natural and the supernatural," as
follows.

Starting with the two entities, those being the
natural and the supernatural, it is quite correct to identify these as disparate,
separate, individual concepts. The natural, of course, is all things pertaining to the
natural world: things that can be seen, heard, touched, tasted, smelled, or otherwise
felt, like wind or heat. The supernatural is all things pertaining to that which is
attested by some to be of this world but not perceived in this world, that which is
beyond the natural [super- is a Latin loanword prefix meaning
beyond or above]: things that can not be seen,
touched, tasted, heard, smelled, or otherwise felt in a natural, normal fashion as you
see a kitten, touch velvet, taste chocolate, hear Mozart, smell toast, or feel
cold.

It cannot literally be said that the natural and the
supernatural can be joined as two separate, disparate, individual entities, but it can
figuratively be said that the natural and supernatural can be joined. This figurative
metaphoric joining results in the idiomatic statement of a marriage between the natural
and the supernatural. In practical terms, if you read or hear this figure of speech ,
you are being told that something, perhaps a poem or a painting, has combined the
qualities of nature with supernatural qualities.

For
instance, say you read a poem that describes a tall old manor house situated up on a
small rise and surrounded closely by pine trees with its windows all open with pairs of
white net curtains billowing gently outward from each window when the weather outdoors
is still and temperate without a cloud or breeze to be seen or felt. You might then say
that this scene presents a marriage between the natural and the supernatural because
only the supernatural can cause curtains to billow outward through windows as though
moved by a mild wind from within. Thus the natural and supernatural have been joined in
a figurative bond or alliance.