Just read up on Ri/Bi :(Case 2 in Mumonkan)

inward and outward action of the mind.
-this or that?
+ or -,
inward or outward?

People are constantly trying to reduce all questions and worries to a single entity,
or God,
if you will.

Where in real life,
simply looking at electricity and the structure of an atom,
both positive and negative(+&-)
are needed to make a charge or reaction.
All life/energy/being is dependant upon this + and - interaction.