Oppositions exist everywhere in our perceived world. They are products of our intuition and thought to such things as man and land, mass and form, to gravity and movement, to permanence and entropy, to material and tools.
I recall one particular instance that happened about 10 or 12 years ago in Northern Wisconsin. I accompanied my dad, brother (5 years older than me), and his boy scout team on a hike along a path in very brisk weather. Along the path, we come up to a designated area before being haulted by a 100 foot drop between a fast-moving river and a bridge comprised of steel rails and wooden ties; it was an abandoned railroad track without hand rails or anything preventing one wrong slip and chaos.
I realize that the original idea was not to transport humans on hands and knees, but this classic hand-made opposition for trains did not make me happy. This train-turned-human bridge supported our team of brave scouts across this devestating drop. Each tie i crossed gave me a view straight down between them. So, an example of different solutions to oppositions result from my experience. No sane human would consider going across that bridge had it still been in service; although, I wasn't quite old enough to determine it for myself and I'm sure my pops wouldn't have told me the truth. Nevertheless, one solution can be abandoned and used for the same purpose (to transport humans across a valley), but in a different way (by foot).
Man/Lighting in order to Move-
Naturally, it is not always bright outside so our obvious response to the lack of sun is alternate sources of LIGHTING; most commonly candles or electric lighting through bulbs. The candles give more of a tranquil and perhaps natural setting; one I enjoy relaxing and working in. On the other hand, electricity is routed throughout cities in most areas since no one place is naturally lit at night. This gives us a visual sense of space to allow comfortable movement around developed space.