A Baltimore mother accused of joining a cult and starving her child says she was acting on her religious beliefs. What's the difference between extreme religious conviction and delusion? Between a religion and a cult?
Children believe that their mothers love them. The proof they have is the same as the proof of God - a subjective feeling. The fact that God is subjective doesn't make the deity unreal, but it radically shifts the burden of proof. All subjective states are personal and therefore impossible to verify objectively. There is no way to tell if two people looking at a daffodil see the same shade of yellow, much less that they are referring to the same thing when they use the word "God." Even brain scans provide nothing more than a rough location for where such thoughts occur, nothing about their validity.
Skeptics make hay out of this situation. In his wildly popular book The God Delusion, Richard Dawkins marshaled the force of science against God almost entirely by making one point over and over: God can't be objectively verified. He didn't seem to realize that the point itself is pointless. Beauty, truth, love, morality, ethics, and every other aspect of our inner life cannot be verified by science, either. Shifting the burden of proof to the inner world leaves scientific measurement behind, but it doesn't make beauty, truth, morality, and the rest false. If I find Picasso beautiful and you don't, our disagreement isn't a matter of who's right and who's wrong. Each person's consciousness is a domain of personal experience that relies on itself. Having a right to your own opinion, however bizarre, is the same as asserting your own awareness.
Of course, the inner and outer world blend, and therefore they sometimes come to blows. Society tends to be happy with organized religion but unhappy with cults (even though organized religion can be defined as a cult with a large following). There's not much debate on the spiritual side when either one breaks the law. Pedophile priests in the Catholic Church are prosecuted, as the members of the One Mind Ministries will be if they participated in starving a child. As for whether any of them are delusional, we refer to psychiatrists to make that determination on a medical basis.
Here again skeptics have a field day. They see no difference between thinking that Christ rose from the dead and thinking that a poor starved child in Baltimore can do the same. But they overplay their hand (Dawkins being particularly egregious) by lumping all spiritual experiences together. Many of the greatest figures in history have had profound spiritual experiences without being delusional. Their experiences have done more to shape human destiny than any other force besides war. To call Socrates, Gandhi, Martin Luther King, and Buddha hopelessly deluded because an academic pedant like Richard Dawkins feels superior to them is absurd.
What this all amounts to is that religion is entangled with the best and worst of human behavior. It is probably unique that way. In the name of loving God devotees have inflicted untold violence and composed the most beautiful poetry and music. It may be past time to radically reform organized religion or even dispense with it altogether (as I tend to believe). But the reason won't be to cleanse the world of delusion. The reason will be that a better, more fulfilled spirituality wants to be born.