UFO Aliens: They cannot be proven not to exist, but there is no rational cause for belief in them, as the energy expenditure necessary to reach us from the nearest potentially industrialized planet is sufficient that they should have attempted some form of contact, peaceful or not, as a return on their investment.

Crop circles: It is possible that some are caused by purely natural occurences, such as freak downdrafts, but in general unlikely. There is no rational cause to believe that some intelligent, nonhuman agency would attempt, as its sole method of contact, making circles in someone's crops.

God: The Judeo-Christian deity, omnipotent, omniscient, and omnibenevolent, cannot exist in light of natural (as opposed to moral, humancaused) evil, but insufficent empirical evidence exists either way for a deity lacking one of these properties.

Political Parties: they are polar factions, and a necessary outgrowth of Western polar thought. They are no more and no less evil than the philosophy that spawns them.

Afterlife: By definition, the afterlife is beyond our current existence; most beliefs regarding it indicate that living humans cannot, in fact, see or otherwise perceive the afterlife in any way. Thus, it is an untestable proposition.