Because, if it was true, then the story of the Virgin Mary was not true. Jesus couldn't have been born in the way the New Testament said he was born. There was no such thing as the Immaculate Conception. You could hardly be expected to believe in it once you knew why it couldn't have happened.
And if the Bible could deceive you about an important thing like that, it could deceive you about the Incarnation and the Atonement. You were no longer obliged to believe in that ugly business of a cruel, bungling God appeased with bloodshed. You were not obliged to believe anything just because it was in the Bible.
But—if you didn't, you were an Infidel.
She could hear Aunt Bella talking to Uncle Edward, and Mrs. Farmer and
Mrs. Propart whispering: "Mary is an Infidel."
She thought: "If I am I can't help it." She was even slightly elated, as if she had set out on some happy, dangerous adventure.
II.
Nobody seemed to know what Pantheism was. Mr. Propart smiled when you asked him and said it was something you had better not meddle with. Mr. Farmer said it was only another word for atheism; you might as well have no God at all as be a pantheist. But if "pan" meant "all things," and "theos" was God—
Perhaps it would be in the Encyclopaedia Britannica. The Encyclopaedia told you all about Australia. There was even a good long bit about Byron, too.
Panceput—Panegyric—Pantheism! There you were. Pantheism is "that speculative system which by absolutely identifying the Subject and Object of thought, reduces all existence, mental and material, to phenomenal modifications of one eternal, self-existent Substance which is called by the name of God…. All things are God."
When you had read the first sentence five or six times over and looked up "Subject" and "Object" and "Phenomenal," you could see fairly well what it meant. Whatever else God might be, he was not what they said, something separate and outside things, something that made your mind uncomfortable when you tried to think about it.