Thinking about Good and Evil

There seems to be 3 different approaches to considering the relationship between good and evil:
1. evil is defined as a lessening of the good

2. evil is defined as the opposite of the good

3. evil is defined a both a lessening of the good, and the opposite of the good

4. evil is defined as good, and, good is defined as evil

Now, the first three definitions have a great deal in common with each other, however, the last defintion -number 4- does not. The last definition seems to be the one used by most satanic cults. Thus, let us also consider number 4, above, using an analygis which employes syllogistic logic:
1. assume that good is defined as evil
2. assume that evil is defined as good
3. from number 1, above, derive: if good then evil
4. from number 2, above, derive: if evil then good
5. if good then evil
6. if evil then good
7 assume good exists
8 assume evil exists
9 combine 5 and 6, and derive: if evil then good and if good then evil
10 if evil then good and if good then evil
11 assume evil
12 combine 10 and 11, and derive: if evil then good, evil, therefore good
13 derive good from 12, above
14 from 10, derive, if good, then evil, good, therefore, evil
15 therefore, from evil you derive good, and from good you derive evil,
and once again from evil you derive good
16 from 15, derive, from good you derive good, and thus, good is good
17 from 15, derive, from evil you derive evil, and thus, evil is evil
18 thus, where evil is defined as good, and, good is defined as evil,
logically, it is true that good is good, and, evil is evil
19 from 18, above, derive: good is good and evil is evil