Why does it feel so natural to write them in that order?

Nature is rife with duality - that is opposing forces or concepts,

From the +/- spin of subatomic particles,

To the cycle of day and night, something almost everyone can see.

So now i will invoke another duality...

Is it the nature of the mind to polarise and split ideas?

Or is the world around us fundamentally cut in two?*

Dichotomies are undoubtedly useful to the human mind,

Humans love to create them as a means to understand life.

So perhaps a tendency to linearise concepts is at the heart of duality:

By polarising a phenomenon into two opposite factors it becomes simple and comprehensible.

However a linearising thought processor begs the question:

What is it about the mind (and of course the brain itself)

That develops this one dimensional understanding?

One obvious lead is of the two hemispheres of the brain.

While the existence of two hemispheres is interesting,

They are unlikely to directly and neatly 'cause' duality in the mind.

Talking about such things it becomes difficult to avoid tripping on tautologies.

And when tautologies litter the path ahead, it is perhaps time to take a new route of ascent*.

The ying yang can be insightful to the nature of duality.

Two poles, extremes, or opponents are in fact tied together inseparably,

Each of the two elements is part of a whole,

And within this understanding lies a philosophical gemstone.

In other words it looks really nice, but it is damn hard to break open.

A more human understanding may shed light onto the problem i've created:

By viewing the world around us in one dimensional, two sided ways we are relating it to ourselves.

Something ancient in the human mind is dualistic, thus by segmenting the outer world also into two,

It becomes relatable, comprehensible, because it is a reflection of ourselves.