Does evil exist?
The ancestors certainly thought so. Looking around me in the world, I can't help but think that they were right.
I sometimes hear pagans dismissing the existence of evil with a cavalier wave of the hand. (I've been there myself.) As, many of us, people of privilege living in a society of privilege—some of us reacting against upbringings obsessed with metaphysical evil—it's easy to be dismissive.
But the ancestors knew about evil long before the coming of the missionaries. 5500 years ago, speakers of the Indo-European Mother Tongue knew evil as *upelo-. 3000 years later, the speakers of Common Germanic spoke of *ubilaz. The Anglo-Saxon tribe known as the Hwicce, the original Tribe of Witches, called if yfel (Watkins 98).
I'm not arguing for the existence of evil as a principle or a metaphysical entity. Although—linguistically speaking—evil may be a noun, it's not a thing in se.