In my previous post, I explained that we always choose something because we believe that it is good in some way and choose it for that reason. But it is obvious that people sometimes choose to do what is evil. When someone chooses to do an evil thing, that choice can be examined in two ways. If we examine the choice insofar as it is evil, the choice is irrational. If we examine the choice insofar as it is good, it is rational.
A evil choice is just a good choice that is missing something. The part that is missing is what makes the evil choice evil rather than good. Therefore, there are two ways of seeing evil choices. We can look at evil choices and consider what is present, or we can consider what is missing. If someone chooses what is evil based on the good that is present there, then their choice is rational. They are choosing something good to achieve something. Their intentions in their choice are fulfilled by the choice they make. The same thing would be true if they chose something good based on the good that the choice was.
The other option is choosing an evil choice based on what is missing. This is irrational. By choosing to do what is evil based on the evilness of the choice (what is missing), you are intending nothing. Therefore, you choice accomplishes nothing. If you intend nothing, then you cannot intend to do an evil choice. Therefore, it is impossible to intend to do something evil based on the evilness of the choice.
If this were all that could be said on this subject, then we might assume that people only do evil out of ignorance. No one ever deliberately does what is evil, knowing that it is evil. But that is not true. So the next stage in explaining evil choices is showing how it is possible to do what is evil while knowing that it is evil.