How could you tell the difference?
Despite common misconceptions, as an atheist I don’t worship the Satan. (Thankfully that misconception is getting less and less common.) So when I ask the question “What if Satan wrote the Bible?”, I’m asking purely for the purpose of understanding the thoughts of believers.
I’m often told by Christians of certain stripes that they know God is good because the Bible says so. And thus, all the things he says in the Bible are good, regardless of how morally reprehensible they may seem to a secular humanist like me.
But if the Bible is all your evidence for God’s goodness, what’s to have stopped some powerful evil being from penning it and calling himself good? It certainly seems to match up with some of the Hebrew scriptures’ more wrathful picture of their deity. Not to mention a few of the more heinous teachings in the New Testament. (I’m looking at you, Paul and Revelation!)
Which brings up another group of believers: those who say it is through private revelation or their own feelings that they know that God is good.
But again, what is to stop a sufficiently powerful evil being from convincing you that it is a good deity? I’m sure many believers think this is in fact the truth about other believers. But how do you know it isn’t true for yourself?
Aren’t you relying on your own feelings and opinions about what is good to determine that God is good and Satan is evil?
And if that’s true, and you have at least somewhat reliable feelings and opinions about good and evil, what’s the need for a god or a holy book to tell you those things?
Think about it.
Of course, with my luck, I’ll have accidentally converted a believer to Satanism with this little thought experiment.