In the sin/temptation model of morality, the choice is central. We can choose to do good, or we can choose to do evil. This seems like an obvious choice, but so often we get it wrong because we are tempted to choose evil. All we have to do is resist temptation and not sin.
I don't know to what extent this is a serious Catholic doctrine, and to what extent it's just the basic morality they teach to the kids. I do know that I'm not a fan.
Even as a kid I didn't like it. If it was just about resisting temptation, that was too easy! As I saw it, the real moral issue was that you didn't know which was the good choice. If you were tempted to do something, that really just meant you believed there was a possibility that it was the right thing to do. Resisting temptation just seemed like a way to ignore moral doubts by immediately declaring one choice to be the right one.
Looking back with a more analytical mindset, I think there are three main points in the sin/temptation model.
- Morality is connected to the supernatural. We were taught that temptation comes from original sin. Temptation is also practically reified into a supernatural entity.
- Morality is about self-control and strength of will. There's right and there's wrong, and all you have to do is pick the right one.
- What is moral and what we want are two different things. We do evil when we prioritize what we want over what is moral.
For instance, I think self-control is a good value. When I was a kid I thought self-control was easy, because I happen to have a lot of self-control. But I no longer think it is easy in all circumstances, or that everyone has it easy. Of course, this raises the question of whether encouraging self-control leads to greater self-control, or if the trait is mostly hard-coded into people. A question for child psychologists.
It is also true that what we want and what is moral are two different things. Sometimes we have two conflicting preferences, one of which is "baser" than the other. For example, a kid might want candy because it's sweet, but also want to stay healthy by not eating too much. And sometimes we're in a Prisoner's Dilemma situation where cooperating is the right way to negotiate our different preferences, but is the wrong way to fulfill our personal preferences.
My problem isn't so much with these values, but with the underemphasis of other important values. I think a lot of practical everyday morality simply has to do with being aware of other people's preferences, and how you are affecting them. It's also about making sure to gather knowledge to make the right choices later on, but also not spending too much time gathering knowledge since gathering knowledge has its own cost. (For instance, my mother takes a long time to pick things to order at restaurants even though it is unreasonable to believe that this significantly improves her decision.)
In short, there are some positive aspects of sin/temptation morality, but I'm not a fan because of the supernatural aspect, and because it pretends that recognizing which choices are the right ones is the easy step.