Flesh and Spirit (1922)

Chemist Donald Wallace is an atheist who believes science is the only God. He is loved by his cousin, Truth Eldridge, but is too self centered and too attentive to his radium experiments to notice her affection. Instead, he falls for Paula Roberts. When they come upon a lost little girl named Peggy, Wallace decides to take care of her until he finds her parents, but despite being a kind man, he insists to the girl that there is no God. James Dale, Wallace's assistant and Truth Eldridge's secret admirer, accidentally kills her when he tries to poison Wallace. Shortly after her death, Truth returns in spirit form to convince Wallace that God exists after all.