There are many ways to classify logical fallacies. I prefer listing the conditions for a good or cogent argument and then classifying logical fallacies according to the failure to meet these conditions
fallacies of assumption
Every argument makes some assumptions. A cogent argument makes only warranted assumptions, i.e., its assumptions are not questionable or false. Fallacies of assumption make up one type of logical fallacy.
One of the most common fallacies of assumption is begging the question. Here the arguer assumes what he should be proving. Most arguments for psi (ESP and psychokinesis) commit this fallacy. For example, many believers in psi point to the ganzfeld experiments as proof of paranormal activity. They note that in many experiments a .25 success rate was predicted by chance but a meta-analysis found a success rate of .34. One defender of psi claims that the odds of getting 34% correct in these experiments was a million billion to one. That may be true, but one is begging the question to ascribe the amazing success rate to paranormal powers. It could be evidence of psychic activity, but there might be some other explanation as well. The amazing statistic doesn't prove what caused it. The fact that the experiment is trying to find proof of psi isn't relevant. If someone else did the same experiment but claimed to be trying to find proof that angels, dark matter, or aliens were communicating directly to some minds, that would not be relevant to what was actually the cause of the amazing statistic. The experimenters are simply assuming that any amazing stat they get is due to something paranormal. I call this assumption the psi assumption.
Another common--and fatal--fallacy of assumption is the false dilemma. Here one assumes that the only reasonable alternatives are the ones you present, when in fact there are others that should not be ignored.This tactic can be persuasive if one of the alternatives is clearly unacceptable.
Not all fallacies of assumption are fatal. Some cogent arguments might make one or two questionable or false assumptions, but still have enough good evidence to support their conclusions. Some, like the gambler's fallacy, are fatal, however. Odds for something with a fixed probability will never increase or decrease depending upon recent occurrences. If the odds were 50/50 before you flipped the coin, they'll still be 50/50 on the next flip--regardless of what side came up on the first flip or the last five or ten flips. (If the coin is loaded, the odds weren't 50/50 to begin with.)
