Some beliefs are hard to shake. The Chinese habit of loudly banging gongs and drums during solar eclipses is one. The reasoning is hard to argue with.
An eclipse is caused by a dragon trying to swallow the sun.
The gongs and drums frighten the dragon into releasing the sun.
Any argument against this idea can be countered by the reasoning that it ALWAYS works.

Comets are harbingers of evil. It's an incontrovertible fact that whenever a comet has appeared in the skies, terrible things have happened.
This would only be significant, of course, if terrible things did NOT happen in the absence of comets.

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This is not an idea to be tossed aside lightly - it should be thrown with great force