Monday, 24 December 2007 12:56Written by Guy Davies
The following (by no means complete) list is an attempt to list some common, everyday logical fallacies, which we will all come across in our everyday lives. Facts or assumptions upon which a viewpoint is based may be logical fallacies. It can be useful to look at information, facts or assumptions that we are presented with and see if they break any logical fallacies...if they do then we should treat them with care. A conclusion based on logical fallacies is more likely to be invalid. If there is any interest then I can attempt to unpack some of them with some examples.
Ad hominem. This argument attacks the person and not the evidence. Very easy mistake to make. If the person has been wrong before, or we don't like the person, then we will tend to treat their information differently to others.
Argument from authority. This is saying that something is true because a person, or people in authority say it is. It is also easy to be falsely led by this - because a person has many degrees, professorships, or whatever, then it does not mean they will be necessarily right.
Argument from final Consequences. Sort of reverse logic. Rather than looking at the cause, and then effect, the effect is taken to prove the cause.
Argument from Ignorance. Also called Ad ignorantiam. Basically saying that X must be true, because we cannot know or understand that it isn't true. It is quite acceptable to state that we don't (or can't) know something.
Argument from Personal Incredulity. Basically saying, that because I cannot understand or explain a fact then it cannot be true. None of us have complete knowledge of everthing, but that cannot mean that something we cannot explain, cannot be true.
Confusing association with causation. Similar to post hoc (below). This can be tricky, but it is the mistaken assumption that a correlation is a cause.
Confusing currently unexplained with unexplainable. Just because we don't have all the answers now, does not mean that at some stage in the future, we may have the answers. It goes back to being able to say "I cannot know that (now)".
False Continuum. Taking a true conclusion beyond the extreme of the knowledge.
False Dichotomy. Reducing an argument to only 2 possible outcomes. It has to be either A or B? Often there are a number of other possible outcomes, which are overlooked / ignored.
Inconsistency. Applying certain criteria to some evidence or positions, but not to others.
The Moving Goalpost. Moving the criteria for 'proof'.
Non-Sequitur. From the Latin, this term translates to "doesn't follow". Fairly obvious making the wrong connection.
Post-hoc ergo propter hoc. Again from the Latin; after this, therefore because of this. Mistakenly confusing cause & effect because of the timing.
Reductio ad absurdum. This is another tricky one, as it can be used properly as a valid argument, but it is open to abuse too. It reduces a position down to basic principles, to disprove the validity of something else.
Slippery Slope. Taking a conclusion to absurd conclusions, going far beyond the reasonable line.
Straw Man. This is when a person does not actually argue against the actual other person's standpoint but creates a similar (false) position, and argues against that.
Special pleading, or ad-hoc reasoning. This is arguing for special considerations for a specific assumption, often after the results of testing have disproved the proposition. It can be claiming that something is true, but when tested and proved to be false, then saying that it will not work under test conditions.
Tautology. Circular logic. saying that the evidence is the premise. A=B because A=B (although often worded differently.
Tu quoque. More Latin - meaning you too. If my evidence is false, then it follows that yours is too.
Unstated Major Premise. Also called begging the question. Basing the assumption on an unproven and unstated initial premise.
These may be useless, or stating the obvious. But I find them useful. This list is not complete, by any means, but they do assist me in logical thinking. I try to watch out for any of the above in discussions, and also try to avoid falling into the trap of using a logical fallacy to defend my own viewpoint. I know I don't always succeed!!
Subscribe to this comment's feed
