THE DEBATE
Nobody disputes that good is real. Evil works against good. There is a debate over what it means to say that evil exists or in other words what evil actually means.
There are two proposed suggestions about how evil is to be understood.
1 - Evil is a substance, a power, a thing. It exists in its own right. We will call that substantial evil.
2 - Evil is only a distortion of good - essentially it is good in the wrong place and time and has no existence of its own. We will call that parasitic evil.
2 is considered to be a prop.
We should be experiencing evil like we do fresh air and then defining it. But no. Many just go for the lack doctrine so they can affirm that there is an all-good and all-powerful creator God of all from nothing. If evil were in any sense real it would follow the creator was to blame for it.
If you affirm cancer because you want to believe the doctors and not because it is real you can imagine the stupidity. Stupidity is open to harm and will often actually harm. In a sense being open to harming is harm.
1 may be open to the notion of pure evil - that the power is totally harmful and or worthless. It is absolute evil. But evil can be corrupting and harming without going that far. Evil does not need to be totally rotten in order to torment a person to the maximum. Pure poison might kill you in a minute but impure poison might take two. The difference could be very slim between both concepts of evil.
If evil is a real energy, whether completely toxic or not, it will hide what it is and/or be at least hard to spot. We never see the full picture for we have personal limitations. Thus it and its servants could give the impression that 2 is true in order to obscure the real danger and the real truth. It may just want to lie full stop or lie to get some advantage. I am using a personalised metaphor here. But if evil is a power it could indeed be a superior intelligence.
Declaring evil to be a substance has interesting conclusions. It could be a pure toxic force that mixes itself up in good. Or it can be partially evil, mixed evil or situational.
There is a contradiction in how we are discouraged from seeing evil as real power, and in how caution would bid us to see it that way even if it is not.
Yet we want to see evil and good as opposites. But theology says that evil is distorted good and not the opposite of good. If God designed us, then why are we designed to wage war against enemies and to treat good and evil as binary opposites?
CS Lewis said that Satan was not all evil for he still had his senses and his reasoning powers and the problem was that he was abusing those good things. He thought that because Satan was still a living being that he was not pure evil. Believers in God confuse evil with nothing. They hold that the more evil a being or thing becomes the more it fades and becomes nothing. This is insane.
Finally
Only evidence and experience should tell us what evil is. It is not a guessing matter or a theological one.
The claim that evil is merely a lack of good is silly. It is based on belief. But belief then because it is the lack of knowledge would itself be evil!