Indiana Jones & Last Crusade: Elsa Question

[Tosk]

The odd thing is that after what happened with the Ark and the Stones, Indy didn't believe in the Grail or its power until now. Think he'd have learned his lesson over skepticism by this point.

That's his MO. He gains belief in one mystical thing, but it doesn't transfer over to all mystical things. I agree with him. If it was proven that unicorns were real, I wouldn't automatically assume that leprechauns were too.