Tuesday, September 7, 2010

Exploring Logical Fallacies

Logical Fallacy. There are two words to this concept; logic and fallacy. Let us first define what those are using the Webster's Encyclopedic Unabridged Dictionary of the English Language (1983, because that is what I have on hand).

Logic: log-ic (loj′ik), n. 1. the science which investigates the principles governing correct or reliable inferences. 2. a particular method of reasoning or argumentation: We were unable to follow his logic. 3. the system or principles of reasoning applicable to any branch of knowledge or study. 4. reason or sound judgment, as in utterances or actions: There wasn't much logic in her move. 5. convincing forcefulness: the irresistible logic of facts.

Logical: (loj′i kəl), adj. 1. according to or agreeing with the principles of logic: a logical inference. 2. reasoning in accordance with the principles of logic, as a person, the mind, etc.: a logical man; logical thinking. 3. reasonable; reasonably to be expected: War was the logical consequence of such threats. 4. of or pertaining to logic.

Fail: (fāl) 1. to fall short of success or achievement in something expected, attempted, desired, or approved: The experiment failed. 2. to receive less than the passing grade or mark in an examination, class, or course of study: He failed in history. 3. to be or become deficient or lacking; fall short; be insufficient or absent: Our supplies failed.

Fallacious: fal-la-cious (fə lā′shəs) 1. deceptive; misleading: fallacious testimony. 2. containing a fallacy; logically unsound: fallacious arguments. 3. disappointing; delusive: a fallacious peace.

Fallacy: (fal′ā sē), n., pl. -cies. 1. a deceptive, misleading, or false notion, belief, etc.: That the world is flat was at one time a popular fallacy. 2. a misleading or unsound argument. 3. deceptive, misleading, or false nature; erroneousness: the fallacy of our trust in such methods was soon apparent. 4. Logic. any of various types of erroneous reasoning that render arguments logically unsound. 5. Obs. deception.

Now, put all that together into one phrase: logical fallacy. In my own words, it is a self-refuting statement. Here are some others:


* A logical fallacy is an element of an argument that is flawed, essentially rendering the line of reasoning, if not the entire argument, invalid.


  • a fallacy is a misconception resulting from incorrect reasoning in argumentation.


  • Clearly defined error in reasoning used to support or refute an argument, excluding simple unintended mistakes.
  • A mistake in reasoning
  • Logical fallacy is an incorrect conclusion derived from faulty reasoning. See also post hoc, ergo propter hoc and non sequitur.

So, now that we have reasonably established what a logical fallacy is, why is it a bad thing to use in an argument? Quite simply, if you use a logical fallacy to support an argument, you are using a weak foundation that fails and your argument has no logical foundation, no standing, no grounds, etc.; it only serves to discredit you and remove yourself from serious consideration on the topic. Logical fallacies ruin the one using them, and everyone else will just point and laugh-depending on the crowd, of course: most might just laugh. Because logical fallacies are failures of logic, you do not have to actually know the name of the specific logical fallacy being used in order to fall into their trap. It is, first and foremost, a failure of logic.

Here are some of the most common with definitions from all over the place:

Straw Man

  • A misrepresentation of an opponent's position
  • A fallacy in which an irrelevant topic is presented in order to divert attention from the original issue. The basic idea is to "win" an argument by leading attention away from the argument and to another topic.

  • Person 1 has position A
  • Person 2 doesn't agree in part or in full with position A, but then presents a superficially-similar position B.
  • Person 2 attacks position B, declaring that position A is therefore false/incorrect/flawed.

Example: "Evolution means a dog giving birth to a cat."

Example: "Evolution says everything came from nothing."

Ad Hominem

  • Attacking the person rather than the argument.
  • Using irrelevant personal distractions about the presenter to avoid the argument.

  • Person 1 makes claim X
  • Person 2 says/creates something objectionable about Person 1
  • Therefore claim X is false

Example: "You are fat, therefore you are wrong about the heliocentric model of the solar system."

Example: "You must be a Cheeto loving slob living in your mother's basement."

This argument is close to a Red Herring, which is another diversionary tactic.

This fallacy does not mean people are free from being offended. The failure of logic is in attacking something personal rather than the argument because the physical condition of the presenter has nothing to do with the intellectual argument. This fallacy does not take effect unless an insult IS the intended refutation of the argument presented. If a logical argument is presented to refute the initial argument, this fallacy does not apply to any additional insults that are not part of the argument itself: that is called being rude or belligerent.

False Dichotomy / False Dilemma / Either-Or Fallacy

  • Asserting there are only two answers to a question which, in fact, there are many more.

  • Person 1 makes a statement or question in which only alternative A or B is offered.
  • Person 1 ignores solution C through Z.

This is also known as a Morton's Fork: a choice between two equally unpleasant options.

Fun fact: An opposite of Morton's Fork is the Buridan's Ass paradox.

Example: "If you are not with us, then you are against us."

Example: "Are you a Christian or an Atheist?"

Example: "If you dont follow Christ, then you believe everything came from nothing!"

Shifting the Burden of Proof

  • Placing the responsibility for validating a position on the wrong party.

In debate, the one who makes the positive claim must validate their position. If someone states their position as fact, they must validate that position. A common misconception is that non-believers must validate their own argument before the believer is supposed to validate their argument. This is generally not the case for the main reason that non-belief in a god is not a factual statement of denial of a god, but a statement of opinion in the lack of belief of a god. It is also impossible to directly prove a negative statement. This goes to the very definition of "atheist" vs "theist.

If someone defines "atheist" as a denial of a specific god, then they must show a definition of "theist" to be a positive belief in that specific god the anti-statement denies. Such a relationship does not exist. If the non-believer makes a factual statement about the non-existence of a specific entity, THEN they have the burden of proof to validate their statement.

The most common position is: "God is real." This must be validated before it can be accepted as truthful. There has yet to be any irrefutable validation for any god(s)/system of gods yet to be presented for the last several thousand years over the many thousands of gods in human culture.

When a factual statement is presented, it is not the responsibility of the opponents of that statement to prove it is not factual. When such a statement is presented, those supporting the statement have the responsibility to prove it is true.

A common tactic from non-believers is to first get the believer to identify specific beliefs they have/rely on to be accurate representations of their religion. Once those specifics are identified, the debate/argument can proceed. Without specifics, there is little to no possibility of satisfactory debate. Religious statements and debates will often substitute words, like "God", to mean the accepted representation of which ever culture the debate happens to be in/about. In the USA, this is most often assumed to be the Christian god. As there are 30,000 some different sects/divisions of the Christian faith, specifics must be defined for rational debate.

"God is real."
"I don't believe in your god."
"You must prove God doesn't exist."

"You can't prove god doesn't exist, therefore he exists."

"The Flying Spaghetti Monster put monkeys in Neptune's core."
"I don't believe that."
"Prove the FSM didn't."

Argument from Authority / Appeal to Authority

  • Asserting that an argument is true because another individual who is regarded as authoritative said so.

  • Person 1 says A is true.
  • Person 1 is authoritative.
  • Therefore, A is true.

This fallacy is used quite often. If someone makes a statement about a field of study or situation well outside of their own understanding or familiarity, their status in unrelated fields has no bearing on the validity on that statement. Clergy have little or no credibility on the subject of Evolution or Quantum Mechanics if they havn't actually studied it. Biologists have little or no credibility on theology if they havn't actually studied it. A seventeen year old minor who proclaims to be a "good Christian" is not an authority on Evolution. A fifty year old retired car salesmen is not an authority on Photolithography.

Biologists ARE an authority on biology. Clergy ARE an authority on their specific religion.

Example: "My parents said so, so it must be true."

Example: "My priest said it was true, therefore it must be true."

Example: "Pat Robertson said the Haiti earthquake was due to a deal with the devil by the Haitians, therefore it is true."

Argument from Popularity / Ad Populum

  • Asserting that something is true because many, most, or all people appear to believe it is true.

  • Lots of people are doing it, therefore it must be good/true.

This is also known as: appeal to the masses, appeal to belief, appeal to the majority, appeal to the people, argument by consensus, authority of the many, bandwagon fallacy, argumentum ad numerum.

The old refutation of this kind of argument asks the person if they would join their fellows in jumping off of a cliff to fall to their death.

Another refutation is to ask the person what they would believe at a certain point in history, and place emphasis on the reason they would believe, knowing how absurd some of them are considered to be today. At one point in our history, we believed the world was flat but that didn't have anything to do with changing reality. We once believed demons caused illness, but again that didn't have anything to do with reality. The point is to ask the person if they would be a "sheep" and follow the crowd because everyone was flocking in a certain direction, or would they accept or follow something else based on intelligent reasons.

Example: "Most of the world believes in religion, therefore there must be a god."

Example: "Everyone else is doing it."

God of the Gaps / Argument from Ignorance

  • An argument that asserts the divine hand of a god into a current gap of scientific knowledge.
  • Asserting the lack of a mundane explanation must prove supernatural intervention.

  • Person 1 points to A and claims their god is responsible.
  • Person 2 shows the naturalistic evidence that explains A.
  • Person 1 points again to a specific aspect of A, claiming B is the work of their god.
  • Person 2 shows the naturalistic evidence that explains B.
  • Person 1 continues searching the gaps in modern science.

  • It cannot be shown that A is true
  • Therefore A is not true

  • It cannot be shown that A is NOT true
  • Therefore A is true

This is most easily defeated by pointing out the obvious: just because there isn't a natural explanation does not prove there is no natural explanation.

This is related to the Moving the Goal Posts fallacy, in which the defender of a position continues to demand different or more complex answers in order to be satisfied. The problem with this is that the goal posts will continue to be moved: the statement or problem sets the person up to fail. This is most often recognized by someone asking for "transitional fossils" or asserting that the "missing link hasn't been found". This stance is most often intentionally dishonest because the real issue is about faith. Faith does not require evidence because it is, by definition, not required, and any evidence presented simply doesn't matter. This begs the question: why bother with what is obviously a rhetorical statement in the first place, then?

Gods were used to explain natural events, like lightening or earthquakes or rough seas. The phenomena that is responsible has been understood. Advocates of a god shift their "proof" to the fringe of our understanding every time a new scientific revelation is founded.

Gods used to be titanic creatures roaming the world, influencing everything we see around us. Now, some will say the god(s) are the force that binds atoms together. The supposed power and observable influence of gods have continued to shrink through the centuries in correlation with our ability to understand more and more about our reality.

Circular Logic / Circular Reasoning / Begging the Question / Fallacy of Redundancy

  • Stating that the consequence of a phenomena is also its cause.
  • An argument that uses its conclusion as one of its premises

While not as common, there are individuals who use this kind of logic to support their belief in a god. See the second example.

"Circular reasoning works because circular reasoning works because..."

"Is there a God?"
"How do you know?"
"Because the Bible says so."
"How do you know the Bible is correct?"
"Because it was inspired by God."

Special Pleading

  • Rejecting a premise or set of rules that would apply, without justification.
  • Exception to generally accepted rules without justifying the exemption.

This comes close to a double standard, or the famous "just because" or "because I said so" excuse. This is a failure of logic because there is no reasonable justification for the resistance to the exemption that would normally be applicable.

"Everything must have a cause, and God was the initial first cause."
"What caused god?"
"God doesn't need a cause."

Cherry Picking / Quote Mining

  • Citing or reporting specific data to support a claim which ignores a larger scope of the data that may refute that claim.
  • Taking something out of context and making a false representation out of it.

This is a very deceptive and intellectually dishonest tactic that basically, and knowingly, lies in order to make an attempt at convincing someone else.

"Even Darwin admitted the eye was too complex in the first sentence of this paragraph!"
"Read the rest of the paragraph, and those that follow, and you will realize he says quite the opposite."

Argumentum Ad nauseam / Argument From Repetition / Argumentum Ad Infinitum

  • Repeating the same thing over and over until the opponent gives up

No matter how many times someone repeats a statement, it does not have any relation to the factual nature of that statement.

Person 1 "God is real."
Person 2 "I dont see any evidence to support that claim."
Person 1 "God is real."
Person 2 "Can you prove it?"
Person 1 "God is real."