There is a famous story told in Chassidic literature that addresses this very question. The Master teaches the student that God created everything in the world to be appreciated, since everything is here to teach us a lesson.
One clever student asks "What lesson can we learn from atheists? Why did God create them?"
The Master responds "God created atheists to teach us the most important lesson of them all - the lesson of true compassion. You see, when an atheist performs an act of charity, visits someone who is sick, helps someone in need, and cares for the world, he is not doing so because of some religious teaching. He does not believe that God commanded him to perform this act. In fact, he does not believe in God at all, so his acts are based on an inner sense of morality. And look at the kindness he can bestow upon others simply because he feels it to be right."
"This means," the Master continued "that when someone reaches out to you for help, you should never say 'I pray that God will help you.' Instead for the moment, you should become an atheist, imagine that there is no God who can help, and say 'I will help you.'"
ETA source: Tales of Hasidim Vol. 2 by Martin Bube
This affect of opposites is symbolically connected to the tree of knowledge of good and evil, law and original sin. Good and evil are the classic or original opposites. Theists and Atheists are also opposites, with the POV of each, sort of against the law of the other. An atheist cannot accept God nor can a theist deny God or they will violate the unwritten laws of their group belief.
This tendency for the human brain to polarize reality into a perception of opposites, is due to the CPU of the ego. This CPU subroutine wiring does not process data part of an integration, but rather divides reality into parts that appear to are opposite of each other. This is the foundation of reasoning, which itself has two distinct aspects in time and space, that are based on opposites; cause and affect. Law of good and evil came first.
This neural CPU of the ego, which subconsciously processes data for the conscious mind, has a tendency to divide reality into opposites; tree of knowledge of good and evil. We do not perceive reality as a unity, but will have an urge and tendency to redefine it in the context of opposites. If we say a certain food is good someone else will see it a yucky, to complete the set. The terrible two's of child develop where the word, "no" appears too often, may be when this CPU starts to kick in. It fixates on the opposite.
The belief in God will need to be opposed by no belief in God. The two polar opposite become part of the law for each, defining the other, as the antagonist to itself. It is a brain game that started with civilization and law. But this has been conditioned into humans, for so long that it appears to be innate. This seems to be connected to the way the left brain works, where the ego migrated, at the time of Adam and Eve; civilization. Instinct is more right brain and has a different way to process data; more 3-D.
Left brain is differential and right brain is more integral in terms of how data is processed. In math differentiation finds the slope of a curve at a given point. While integration finds the area under the curve from A to B. The slope, is based on the angle at a point on a curve, needs two coordinates (X,Y) that are different but connected.
One would need an update in the operating system of the brain, to leave this classic Satan CPU writing and migrate to the other core CPU that processes in 3-D, so opposites can be seen as parts of the whole; tree of life.
If you look at the two main political parties in the USA, they approach public service as opposites. They both are trying to help the common good, but each has a different view of the common good. They see each other as the enemy, thereby limiting their perception of what is the common good, based to their own polarized niche as one of the opposites. The same thing also occurs for the theist and the atheists. Faith places one in contact with the third alternative, since this connects us to the right brain.
If you look at love, such as in the family, love can overcome opposites. One can have two children who are total opposites. Rather than antagonize them and polarize them even more to the nth degree, love places them under the same umbrella of the family, as parts of the whole, that complement each other, to make the family complete. Love is not something one can do on command, but often it happens to you via fate, so this approach is not yet innate and/or continuous for most. The ego is still stuck in the left brain which has advantages; reason, but is also the source of polarizations within the subjectivity of human nature.
The primitive fear of novelty has a connection to this current ego CPU. When something new appears, there is no opposite, day one, since it is new and self standing. The CPU prefers it be defined in terms of a polarization. So it is no longer just new and exciting, but also old and scary to complete the opposite. The rewards of Heaven also has an opposite, which is the punishment of Hell. It is hard to have one without the other, since each set help to contrast, the other so we can differentiate it even better; better slope. The shadow side of the personality, that lies below the ego, follows us like our shadow from the sun. Within the light of the sun is the shadow so the 2-D is made complete; Satan CPU.
