As we continue in Genesis, we see the second big issue that we have to face for a Biblical doctrine of anthropology. (Again, I'm using "anthropology" in its theological, not scientific, definition.) Chapter 3 unfolds the saddest story in human history: the Fall. Adam and Eve were created good, in the image of God, and given just one command to obey. Yet enticed by the temptation of the serpent, first Eve, then Adam violated that command. They did get what the serpent promised, a knowledge of good and evil, but only by engaging in evil themselves.
The result of Adam's choice was the entry of sin into the world, not only for Adam and Eve but for all of humanity. Paul deals with this in 1 Corinthians 15, where he compares the arrival of sin through the first Adam with the arrival of redemption through Jesus, the "second Adam." Sin permeates all of humanity, and as a result all people are guided by a fallen, sinful, selfish nature that must be reborn to be made right with God.
Modern culture tells us that people are all basically good, and that if we only provide the right education, finances, and opportunity people will behave properly and do what is right. The inner drive of humanity, according to this view, is to be good and to do right. We are good, and only become evil when we are deprived of what we need materially, emotionally, and spiritually, so if we make the world a better place all evil will end.
Here we can rely on empirical observation. As we see the news, read the headlines, and observe our family members, colleagues, and friends, which do we see people drawn to: doing what is right or wrong? Do people, knowing that certain behavior is destructive for them physically, mentally, and relationally, then refuse to engage in that behavior? Which do you have to teach a new baby to do: be good, share, and cooperate, or be selfish, rebellious, and self-centered? If we are honest, our observations show us that people are, at their very core, evil.
That's why there are laws, rules, and governments. Evil must be restrained. Good must be promoted. We won't do the right thing unless we are taught it and sanctioned for doing the opposite. Evil somehow manages to thrive despite all attempts to restrain it, demonstrating just how ingrained it is in the human heart.
Which view you hold on this issue sways what you believe about the need for God. If we really are good and can perfect ourselves, we have no need for any god, since we are effectively god to ourselves. But if we see our own corruption and selfishness, we will recognize that we need something bigger than us, even bigger than all of humanity, to change us and make us the good we want to be.
Unfortunately, the dismissal of the divine does not tend to make people better, but worse. This aligns with what we see in human behavior. It also underscores a need to seek for something beyond us which can bring about the kind of change we need personally and societally to make the world a better place.