What is the psychology behind having conflict between good and evil?

It is simply a matter of perspective. The reality is this

Because without one the other would not exist.
We are here to learn lessons and to teach tolerance,compassion etc

Because man refused to acknowledge the true origin of either.

I think it is a simple overblown outgrowth of the tribal “us vs them” mentality.
Makes it easy to define “enemies”.
You are good, they are evil.

A developing consciousness, a learning person, needs a dualistic understanding of the world in order to form a moral structure, a comprehension of right and wrong. With that understanding the ego can proceed with a guide as it begins to explore its place in the world.

It is only later on in understanding that a person realizes that the world is not “yes/no” but rather “yes/and”. And when that arises, the conflict between good and evil dissipates and the yin and yang of life bestows an understanding of the cosmos.

That is a Judeo-Christian—many eastern Asians believe in a table top, with evil just being a different place on the table but not in conflict. At least that was what I was taught.

If everyone were good, the least good person would be called evil.

Worshipping different or no gods. US vs. THEM.

Everybody wants their side to win.

Generally speaking, I do not believe in evil.

Most, if not all, villains believe themselves right or justified in their actions. There are very few true “Chaotic Evils” in the world. Very few who just want to watch the world burn.

I agree with @Seek. There is no such thing as gratuitous evil. Those people who we view as evil do not see themselves as being evil and, if their world view differs sufficiently from ours, may view us as being evil. There may be a conflict between one’s self-interest and the interests of others, or between one’s group and other groups, but that does not relate to evil.

Could you give an example of someone being torn between good and evil?

I think evil is real but we created it. Nature is like the honey badger, it does not give a shit. We do and it’s almost like the act of caring about things is the fertile ground we use to cultivate and define evil. We need it to define our social behavior, otherwise we would have no context for anything.

Though it may seem that an infant is selfish, survival necessitates a focus on its biological needs. Even before consciousness of self and others has developed, an infant’s instinctive behavior is designed to manipulate others to meet its needs. However as consciousness develops, the child becomes increasingly aware of its own existence, the existence of others and its separation from them. The quality of nurturing received and behaviors witnessed during formative years shape the proportion of altruistic and selfish inclinations that emerges with biological maturation.

The struggle between good and evil does not arise from external entities. It is not a war between God and the Devil played on the battlefield of an individual’s soul. It is between our predilection is to be self-serving and a sense that there is virtue in helping others. While no one can be wholly selfless, by adding an awareness of the needs of others to that of our own desires one can reduce their contribution to the evil that seems to prevail in the world and increase the good. This is spiritual maturation.

@Bill1939 The struggle between good and evil does not arise from external entities. It is not a war between God and the Devil played on the battlefield of an individual’s soul. It is between our predilection is to be self-serving and a sense that there is virtue in helping others.
Are you suggesting there is some deep seeded need in humans to selflessly help other people? What would the aim of that be less a selfish need to feel liked, or to be a ”good person”, etc.? What if someone thought it was good policy to wipe out anyone perceived to be a threat, either in the immediate timeframe or in the future, would not they be right in their thinking and believe they were acting rational as to preserve their own existence. Those who are decimated by said person or like band of people would see them as evil but the person inflicting them with misery will be doing so because they see them (those who are being decimated) as evil, so who would be truly correct?

There is plenty of evidence in human history, neuroscience, and the animal kingdom to support an evolutionary tendency toward selfless behaviour. Humans are social animals – we have operated in groups of family units and work-units for many thousands (perhaps millions) of years.

Here a fascinating article discussing the benefits of altruism in groups. It’s a bit of a read, but the last line is a nice summary: “Selfishness beats altruism within groups. Altruistic groups beat selfish groups. Everything else is commentary.”

@Hypocrisy_Central asks some good questions that I will try to answer. ”[Is there] some deep seeded need in humans to selflessly?” I think there is, though not without a self-serving aspect. Upon hearing another child cry infants respond in a way that seems to be more concern than curiosity. It is not unusual for toddlers to seek to comfort a distressed peer. Often children will spontaneously share snacks and toys with others.

I am paraphrasing what I believe you are asking in your second question. Is the aim of what appears to be selflessness actually “a selfish need to feel liked, or to be a ‘good person’, etc.?” Dependent upon adults to insure survival, an innate fear arises when nurturing seems to be threatened, as when a significant adult becomes sad or angry, and the child will seek to ameliorate it; this behavior is evident in many domesticated animals as well. In a sense, seeking to diminish anxiety is self-serving. One might see seeking approval and acceptance from others or to be seen as a good person as selfish. However, to accomplish their intention the child would need to give approval and acceptance to those it sees as a good person.

What is “perceived to be a threat” depends upon the form that the threat takes. People whose intent is unknown are likely to be regarded as a potential threat. Should they appear to be friendly their approach will be cautiously tolerated; trade between tribes would never have happened if all strangers were attacked. When resources are limited, however, groups will muster forces to attack or defend. Each will regard themselves as “good” and the others as “evil”. Neither is either. Animal instinct for survival, which is amoral, will trump any desire for altruism they may have.

^ Often children will spontaneously share snacks and toys with others.
Just as often, if not more, mercilessly tease and bully other kids for being different or unpopular, not to mention being stingy and selfish, wanting to hoard things to themselves.

When resources are limited, however, groups will muster forces to attack or defend. Each will regard themselves as “good” and the others as “evil”. Neither is either.
Which always comes back to no author of good or evil means there is no good or no evil, just opinion based on what any certain person or group likes.

@Hypocrisy_Central having been one of their victims throughout elementary school, I am only too familiar with children that “mercilessly tease and bully other kids.” However, these children are usually older than toddlers. Most undesirable behaviors are learned. I suspect that these and the “stingy and selfish” children were raised in an unhealthy emotional environment.

We have this conflict because we all want to do our best…unless one is a psychopath. They don’t care about good or evil!