Logical Fallacies Flashcards
Explain the Ad Hominem logical fallacy.
An ad hominem argument is any that attempts to counter another’s claims or conclusions by attacking the person, rather than addressing the argument itself.
Give a real-world example of the Ad Hominem logical fallacy.
True believers will often commit this fallacy by countering the arguments of skeptics by stating that skeptics are closed minded. Skeptics, on the other hand, may fall into the trap of dismissing the claims of UFO believers, for example, by stating that people who believe in UFO’s are crazy or stupid.
“John is a jerk. John’s argument is wrong because he is a jerk” Name the logical fallacy.
Ad Hominem.
Are there known variants of the Ad hominem logical fallacy?
A common form of this also has its own name – Godwin’s Law or the reductio ad Hitlerum. This refers to an attempt at “poisoning the well” by drawing an analogy between another’s position and Hitler or the Nazis.
Explain the Ad ignorantiam logical fallacy.
The argument from ignorance basically states that a specific belief is true because we don’t know that it isn’t true.
Give a real-world example of the Ad ignorantiam logical fallacy.
Defenders of extrasensory perception, for example, will often overemphasize how much we do not know about the human brain. It is therefore possible, they argue, that the brain may be capable of transmitting signals at a distance.
Almost all UFO eyewitness evidence is ultimately an argument from ignorance – lights or objects sighted in the sky are unknown, and therefore they are alien spacecraft.
Intelligent design is almost entirely based upon this fallacy.
The core argument for intelligent design is that there are biological structures that have not been fully explained by evolution, therefore a powerful intelligent designer must have created them. This type of argument is often referred to as a “god of the gaps” argument.
What is wrong about the ad ignorantiam logical fallacy?
In order to make a positive claim positive evidence for the specific claim must be presented. The absence of another explanation only means that we do not know – it doesn’t mean we get to make up a specific explanation.
Explain the Argument from authority logical fallacy.
The basic structure of such arguments is as follows: Professor X believes A, Professor X speaks from authority, therefore A is true.
Are there subtypes of the argument from authority logical fallacy?
There are many subtypes of the argument from authority, essentially referring to the implied source of authority.
A common example is the argument ad populum – a belief must be true because it is popular, essentially assuming the authority of the masses.
Another example is the argument from antiquity – a belief has been around for a long time and therefore must be true.
Explain the Argument from final Consequences logical fallacy.
Such arguments (also called teleological) are based on a reversal of cause and effect, because they argue that something is caused by the ultimate effect that it has, or purpose that is serves
Give a real-world example of the Argument from final consequences logical fallacy.
One type of teleological argument is the argument from design. For example, the universe has all the properties necessary to support life, therefore it was designed specifically to support life (and therefore had a designer).
Explain the Argument from Personal Incredulity logical fallacy.
I cannot explain or understand this, therefore it cannot be true.
Explain the Begging the Question logical fallacy.
The intended meaning is to assume a conclusion in one’s question.
Give an example of a begging the question fallacy.
The classic example of begging the question is to ask someone if they have stopped beating their wife yet. Of course, the question assumes that they ever beat their wife.
Explain the Confusing association with causation logical fallacy.
This is similar to the post-hoc fallacy in that it assumes cause and effect for two variables simply because they occur together. This fallacy is often used to give a statistical correlation a causal interpretation.
Being skeptical of association-causation logics can lead to…
applied inappropriately, to deny all statistical evidence. In fact this constitutes a logical fallacy in itself, the denial of causation. This abuse takes two basic forms. The first is to deny the significance of correlations that are demonstrated with prospective controlled data, such as would be acquired during a clinical experiment. The problem with assuming cause and effect from mere correlation is not that a causal relationship is impossible, it’s just that there are other variables that must be considered and not ruled out a-priori. A controlled trial, however, by its design attempts to control for as many variables as possible in order to maximize the probability that a positive correlation is in fact due to a causation.
Explain the Confusing currently unexplained with unexplainable logical fallacy.
Because we do not currently have an adequate explanation for a phenomenon does not mean that it is forever unexplainable, or that it therefore defies the laws of nature or requires a paranormal explanation.
Give a real-world example of the confusing currently unexplained with unexplainable logical fallacy.
An example of this is the “God of the Gaps” strategy of creationists that whatever we cannot currently explain is unexplainable and was therefore an act of god.
Explain the False Analogy logical fallacy.
A false analogy is an argument based upon an assumed similarity between two things, people, or situations when in fact the two things being compared are not similar in the manner invoked.
Explain the False continuum logical fallacy.
The idea that because there is no definitive demarcation line between two extremes, that the distinction between the extremes is not real or meaningful: There is a fuzzy line between cults and religion, therefore they are really the same thing.
Explain the False Dichotomy logical fallacy.
Arbitrarily reducing a set of many possibilities to only two..
Explain the Genetic Fallacy.
The term “genetic” here does not refer to DNA and genes, but to history (and therefore a connection through the concept of inheritance). This fallacy assumes that something’s current utility is dictated by and constrained by its historical utility.
Give an example of the genetic fallacy.
This is easiest to demonstrate with words – a word’s current use may be entirely unrelated to its etymological origins. For example, if I use the term “sunset” or “sunrise” I am not implying belief in a geocentric cosmology in which the sun revolves about the Earth and literally “rises” and “sets.
Explain the Inconsistency logical fallacy.
Applying criteria or rules to one belief, claim, argument, or position but not to others.
Give an example of the inconsistency logical fallacy.
For example, some consumer advocates argue that we need stronger regulation of prescription drugs to ensure their safety and effectiveness, but at the same time argue that medicinal herbs should be sold with no regulation for either safety or effectiveness.
Explain the No True Scotsman logical fallacy.
This fallacy is a form of circular reasoning, in that it attempts to include a conclusion about something in the very definition of the word itself. It is therefore also a semantic argument. The term comes from the example: If Ian claims that all Scotsman are brave, and you provide a counter example of a Scotsman who is clearly a coward, Ian might respond, “Well, then, he’s no true Scotsman.”
Explain the Non-Sequitur logical fallacy.
In Latin this term translates to “doesn’t follow”. This refers to an argument in which the conclusion does not necessarily follow from the premises. In other words, a logical connection is implied where none exists.
Explain the Post-hoc ergo propter hoc logical fallacy.
This fallacy follows the basic format of: A preceded B, therefore A caused B, and therefore assumes cause and effect for two events just because they are temporally related (the latin translates to “after this, therefore because of this”).
Give an example of the Post-hoc ergo propter hoc fallacy.
This is often encountered with health claims: I was sick, a took a treatment, and now I am better, therefore the treatment made me better. Of course, it’s possible the illness resolved “on its own”.
Explain the Reductio ad absurdum logical fallacy.
In formal logic, the reductio ad absurdum is a legitimate argument. It follows the form that if the premises are assumed to be true it necessarily leads to an absurd (false) conclusion and therefore one or more premises must be false. The term is now often used to refer to the abuse of this style of argument, by stretching the logic in order to force an absurd conclusion.
Give an example of the reductio ad absurdum logical fallacy.
For example a UFO enthusiast once argued that if I am skeptical about the existence of alien visitors, I must also be skeptical of the existence of the Great Wall of China, since I have not personally seen either. This is a false reductio ad absurdum because he is ignoring evidence other than personal eyewitness evidence, and also logical inference. In short, being skeptical of UFO’s does not require rejecting the existence of the Great Wall.
Explain the Slippery Slope logical fallacy.
This logical fallacy is the argument that a position is not consistent or tenable because accepting the position means that the extreme of the position must also be accepted. But moderate positions do not necessarily lead down the slippery slope to the extreme.
Explain the Special pleading, or ad-hoc reasoning, logical fallacy.
This is a subtle fallacy which is often difficult to recognize. In essence, it is the arbitrary introduction of new elements into an argument in order to fix them so that they appear valid.
Give an example of the Special pleading, or ad-hoc reasoning, logical fallacy.
A good example of this is the ad-hoc dismissal of negative test results. For example, one might point out that extrasensory perception (ESP) has never been demonstrated under adequate test conditions, therefore ESP is not a genuine phenomenon. Defenders of ESP have attempted to counter this argument by introducing the arbitrary premise that ESP does not work in the presence of skeptics. This fallacy is often taken to ridiculous extremes, as more and more bizarre ad hoc elements are added to explain experimental failures or logical inconsistencies.
Explain the Straw Man logical fallacy.
A straw man argument attempts to counter a position by attacking a different position – usually one that is easier to counter. The arguer invents a caricature of his opponent’s position – a “straw man” – that is easily refuted, but not the position that his opponent actually holds.
Explain the Tautology logical fallacy.
Tautology in formal logic refers to a statement that must be true in every interpretation by its very construction. In rhetorical logic, it is an argument that utilizes circular reasoning, which means that the conclusion is also its own premise. Typically the premise is simply restated in the conclusion, without adding additional information or clarification. The structure of such arguments is A=B therefore A=B, although the premise and conclusion might be formulated differently so it is not immediately apparent as such.
Give an example of the Tautology logical fallacy.
For example, saying that therapeutic touch works because it manipulates the life force is a tautology because the definition of therapeutic touch is the alleged manipulation (without touching) of the life force.
Explain The Fallacy Fallacy
A conclusion may happen to be true even if an argument used to support it is not sound. I may argue, for example, Obama is a Democrat because the sky is blue – an obvious non-sequitur. But the conclusion, Obama is a Democrat, is still true.
Explain the The Moving Goalpost fallacy.
A method of denial that involves arbitrarily moving the criteria for “proof” or acceptance out of range of whatever evidence currently exists. If new evidence comes to light meeting the prior criteria, the goalpost is pushed back further – keeping it out of range of the new evidence.
Explain the Tu quote fallacy.
Literally, you too. This is an attempt to justify wrong action because someone else also does it. “My evidence may be invalid, but so is yours.”
