- There is some sort of reasonable support for.
- There is not conclusive evidence against.
- The possibility seems reasonable, even if unlikely.
If it's completely out of left field and seems to make no sense, though, my window of acceptability diminishes. But I'll always entertain new arguments/proof.
And I don't think that astrology and fairies are probable at all.
Note: Tagging makes a big difference. I'm much more likely to file away an idea if I can tag it as "xx% likely," regardless of the value of xx.