Saying people can’t change is the same as saying people can’t learn.When you learn something new that knowledge fundamentally changes you. Each piece of information adds to your personal database, creating additional resources to draw on when interacting with the outside world. We face the same temptations to engage in negative behavior, but we also build a body of experience that tells us the reward isn't worth the penalty.
In a sense we’re always changing and always staying the same. When I compare my self of today with my self from a few years ago, I observe that I’m the same but more. I’m the same in how I think and process information but experience has changed the way I interpret everything. Every day adds a new layer of character.
"We should anticipate aging with optimism rather than dread. As we grow old the beauty steals inward (Emerson)."
The saying “people don’t change” is harmful because it denies the possibility of redemption. There is something profound about the redeemed. The man who’s experienced the lowest rung of existence and conquered his personal demons has an empathy that’s lacking in more saintly people. In a society supposedly built on the doctrine of forgiveness, it’s remarkable how eager we are to label people as permanent degenerates. Circumstances and hardship leads many good people to do foolish things. To say those mistakes are irredeemable is hypocritical. If the world considered only your most depraved moments, how would you be judged?
People do change. We make every decision for the first time with no obligation to the past. If we control anything, we control our own thoughts and behavior. If can improve anything, it should be ourselves.