What are the two views of nature contrasted in Act 1 Scene 2 of King Lear?

Shakespeare plays upon the double meaning of the word
"nature" in this scene.

The action of the scene revolves
around the setting in motion of the main subplot of the play -- the hoodwinking of
Gloucester by his illegitimate son, Edmund, into believing that his legitmate son, Edgar
has turned against his father.  Edmund is intent upon having Glocester disinherit his
half-brother so that he may be the one to claim his father's
lands.

The double meaning comes in at the beginning and the
ends of the scene.  In his opening soliloquy of the scene, Edmund confides to the
audience that he is bound in "service" to the law of nature.  By this, he exposes his
dissatisfaction with the laws of man (rather than nature) that would brand him an
outsider because he is born a bastard.  He questions:

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. . .Why bastard?  Wherefore
base?

When my dimensions are as well
compact,

My mind as generous, and my shape as
true

As honest madam's issue?  Why brand they
us

With base?  With baseness?  Bastardy?  Base,
base?

And he goes on to point
out that "in the lusty stealth of nature" that he is fare more fit and suited to have
position and power that the those that come from "a dull, stale, tired bed"  -- meaning
his brother.  This argument is Edmund's reasoning for convincing his father to believe
that his brother is a turncoat.  In this soliloquy, Edmund examines his own "nature" as
contrasted with that of his more do-gooding brother and finds his own qualities of
person, not birth, to render him the superior man.

Later,
once Gloucester has swallowed Edmund's story, hook-line-and-sinker, Shakepseare brings
in the other meaning of "nature" when Gloucester, searching for some external cause that
his true and loyal son Edgar should turn against him, blames Nature, by way of cursing
the aligment of the moon and stars.  He says:

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These late eclipses in the sun and moon portend
no good to us.  Though the wisdom of Nature can reason it thus and thus, yet Nature
finds itself scourged by the sequent effects:  love cools, friendship falls off,
brothers divide. . .in palaces, treason; and the bond cracked 'twixt son and
father.

And Edmund ends this
part of the scene with a scornful dismissal of this superstitious appraisal of Nature. 
He does not believe that the events of the stars decide his future.  He believes himself
to be the architect of his future not the external movements of the natural world.  So
Edmund believes it to be his own "nature" rather than "Nature" that decides his
course.

In this scene the meaning of nature (as being one's
character and tendency towards certain behaviours) is contrasted with the forces of the
natural world (ie Nature).  For more on "nature" in this play and Act I, scene ii,
please follow the links below.