One of the most common arguments from the religious is that without God there would be no morality. Non-believers reject this, and there’s an easy though experiment way to see which side you fall on. So, to those who do subscribe to a mainstream religion such as Christianity, Judaism, or Islam, consider this:
Imagine that one day God comes to earth and announces a new rule that says it’s a moral responsibility of all believers to kill anyone who doesn’t have a copy of your religion’s Holy book in his/her house.1.
The question is: would you instantly accept this as morally acceptable because it came from God, or would you reject it because it’s wrong to kill someone for such a thing?
And here are the results. If you would immediately start killing people because God told you to (and therefore the command was “moral” by definition), then your morality comes from God. But if you would question and/or reject this command because it feels “wrong” to you, then your morality comes from somewhere else.
Which are you?
1 Forget the silliness of this particular rule; it doesn’t matter. Besides, God asked Moses to kill a man for gathering wood on the Sabbath, so strange requests aren’t without precedent. And don’t cop out by saying, “My God would never make such a rule, so it’s pointless to discuss.” This is the whole point of a hypothetical–to see what you would do. You don’t have to accept it as an actual possibility.