Of course evil exists. It's hardly a paradox. Evil is something that is morally and ethically "not right". It's not a supernatural essence that can infiltrate the human body and cause mischief. That's just silly.
"...the illegality of cannabis is outrageous, an impediment to full utilization of a drug which helps produce the serenity and insight, sensitivity and fellowship so desperately needed in this increasingly mad and dangerous world."
- Carl Sagan