Top 20 Logical Fallacies

November 13, 2007 | By | 3 Replies More

Here’s a good list of some of the most common logical fallacies. Succinct and clear-cut.

How common are these fallacies? The better question is to determine whether there is any corner of society where you don’t hear people constantly engaging in such reasoning.


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Erich Vieth is an attorney focusing on consumer law litigation and appellate practice. He is also a working musician and a writer, having founded Dangerous Intersection in 2006. Erich lives in the Shaw Neighborhood of St. Louis, Missouri, where he lives half-time with his two extraordinary daughters.

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  1. Niklaus Pfirsig says:

    Something to note: The list of logical fallacies at the link do not go into much detail. For example, Anyone challenging a false authority may be accused of an ad hominem attack on the false authority. This is what Isaac Asimov refered to as a Judo argument, or an argument that attempts to use an opponents strenght against him.

    In the global warming debate, I became curious of the qualifications of the scientists in the IPCC, who formed the concensus that global warming is the result of co2 emmisions caused by human activity. Working my way through the IPCC list of contributors, which is difficult since each scientist's bio must be searched for individually, I have so far found 1 climatologist, 1 meteorologist, a biologist, a chemist, an engineer and an economist. The meteorologist published a paper a few years ago that the climate is cooling toward another ice age.

    In an "Inconvienent Truth" Mr Gore uses a chart comparing a graph of temperature and co2 levels from ice core data. The chart clearly shows a co-relation between the two, and Mr Gore show this as proof that co2 directly causes the global warming. He fails to mention that the co2 levels actually trail the global average temperature by about 800 years, in other words, 800 years after a temperature peak, we have a peak in co2 levels. With this knowledge, it is clear that co2 does not cause global warming. However, it doesn't mean that global warming causes co2 to increase. It is possible that co2 levels and global warming are both co-effects of some other cause.

    The media blasts us with reports of how a majority of scientists or climatologists believe that human activity is causing global warming, yet I have found no evidence of a survey of climatologists that lists any numbers or scores for the climatologists. I have found one reference to a petition signed by 19,000 scientists that disagree with Gore and the IPCC.

    Logic tends to take a flying leap out the window when the media looses it objectivity. With todays sensationalism. It seems that happens everyday. Don't let pseudoscience become your religion.

    It seems that now, you must question every thing that your hear on the politically driven media in this coountry.

  2. Dan Klarmann says:

    The fun thing about public discussion of scientific issues is that the American Public isn't even well enough educated to determine who is a valid authority for a given field, much less to judge the repercussions of a complex issue.

    This goes well beyond the ability to spot applications of logical fallacies (intentional or not). One can build a logically consistent and impeccable case on top of invalid assumptions that only an expert might be able to detect. But no one would be able to convey this inaccuracy to a significant portion of the voting public.

    Look at the global warming naysayer "truth" that trees are growing faster because of increased CO<sub>2</sub>, therefore CO<sub>2</sub> will be absorbed faster. Let's say (for the sake of argument) that this is a repeatable measurement (i.e: True).

    But trees don't actually sequester any noticeable amount of carbon. A tree grows and stores carbon in its wood. Then it is cut down and used. within a century or two of its sprouting, most collected tree-carbon is back in the air from burning or biological decay of the wood. The rate at which trees are cut is still growing significantly faster by orders of magnitude than the rate at which trees are supposedly growing faster.

    The argument may be valid, and the point convincing. But the overall effect is moot to the overall argument.

    (The correct answer to "what life form sequesters the most carbon?" is: shellfish (plankton, clams, diatoms, etc). Most sequestered carbon is found in limestone, a substance that cannot even form until a planetary crust is cooled below red hot.)

  3. Ben says:


    The beginning of the last Millennium saw a "Medieval Warm Period" when temperatures, certainly in Europe, were higher than they are now. Grapes grew in northern England. Ice-bound mountain passes opened in the Alps. The Arctic was warmer in the 1930s than it is today.


    There have been many periods in Earth history that were warmer than today – if not the MWP, then maybe the last interglacial (125,000 years ago) or the Pliocene (three million years ago). Whether those variations were caused by solar forcing, the Earth's orbital wobbles or continental configurations, none of those causes apply today. Evidence for a Medieval Warm Period outside Europe is patchy at best, and is often not contemporary with the warmth in Europe. As the US National Oceanographic and Atmospheric Administration (Noaa) puts it: "The idea of a global or hemispheric Medieval Warm Period that was warmer than today has turned out to be incorrect". Additionally, although the Arctic was warmer in the 1930s than in the following few decades, it is now warmer still.


    Ice-cores dating back nearly one million years show a pattern of temperature and CO2 rise at roughly 100,000-year intervals. But the CO2 rise has always come after the temperature rise, not before, presumably as warmer temperatures have liberated the gas from oceans.


    This is largely true, but largely irrelevant. Ancient ice-cores do show CO2 rising after temperature by a few hundred years – a timescale associated with the ocean response to atmospheric changes mainly driven by wobbles in the Earth's orbit. However, the situation today is dramatically different. The extra CO2 in the atmosphere (35% increase over pre-industrial levels) is from human emissions. Levels are higher than have been seen in 650,000 years of ice-core records, and are possibly higher than any time since three million years ago.

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