Slouching Towards Oblivion

Showing posts with label logical fallacy. Show all posts
Showing posts with label logical fallacy. Show all posts

Thursday, May 22, 2014

Logical Fallacy # 14 - Band Wagon


Just try to remember that once upon a time (1974), the Ford Pinto was the best-selling car in the US - and that was after it was discovered they had an annoying tendency to explode (of course that little gem of consumer information would be a well-guarded secret for another 3 years, but that's a different rant - or better yet, just watch Fight Club again).

Friday, May 16, 2014

Logical Fallacy # 13 - The Gambler's Fallacy




The gambler's fallacy, also known as the Monte Carlo fallacy or the fallacy of the maturity of chances, is the mistaken belief that if something happens more frequently than normal during some period, then it will happen less frequently in the future; likewise, if something happens less frequently than normal during some period, then it will happen more frequently in the future (presumably as a means of balancing nature). In situations where what is being observed is truly random (i.e. independent trials of a random process), this belief, though appealing to the human mind, is false. This fallacy can arise in many practical situations although it is most strongly associated with gambling where such mistakes are common among players.

Thursday, April 24, 2014

Logical Fallacy #11 - Burden Of Proof


When debating any issue, there is an implicit burden of proof on the person asserting a claim. An argument from ignorance occurs when either a proposition is assumed to be true because it has not yet been proven false or a proposition is assumed to be false because it has not yet been proven true.[1][2] This has the effect of shifting the burden of proof to the person criticizing the assertion, but is not valid reasoning.[3]

While certain kinds of arguments, such as logical syllogisms, require mathematical or strictly logical proofs, the standard for evidence to meet the burden of proof is usually determined by context and community standards.[4][5]
In public discourse[edit]

Burden of proof is also an important concept in the public arena of ideas. Once participants in discourse establish common assumptions, the mechanism of burden of proof helps to ensure that all parties contribute productively, using relevant arguments.[6][7][8][9]
Proving a negative[edit]

When the assertion to prove is a negative claim, the burden takes the form of a negative proof, proof of impossibility, or mere evidence of absence. If this negative assertion is in response to a claim made by another party in a debate, asserting the falsehood of the positive claim shifts the burden of proof from the party making the first claim to the one asserting its falsehood, as the position "I do not believe that X is true" is different to the explicit denial "I believe that X is false".[10]
Example[edit]

Matt Dillahunty gives the example of a large jar full of gumballs to illustrate the burden of proof.[11][12] It is a fact of reality that the number of gumballs in the jar is either even or odd, but the beliefs a person could hold are more complicated. We can choose to consider two claims about the situation, given as
The number of gumballs is even.
The number of gumballs is odd.

These two claims can be considered independently. For each claim, because of the law of excluded middle, we are forced to either believe or not believe. Before we have any information about the number of gumballs, we have no means of distinguishing either of the two claims. All of the information we have applies to claim 1 in exactly the same way it applies to claim 2. Due to the law of noncontradiction we cannot accept both of the two mutually exclusive claims, so we must reject (or not believe) both. This is the default position, which represents the null hypothesis. The justification for this position is only ever the lack of evidence supporting a claim. Instead, the burden of proof, or the responsibility to provide evidence and reasoning, lies with those seeking to persuade someone holding the default position.

Monday, April 21, 2014

Logical Fallacy #10 - Loaded Question


A loaded question or complex question fallacy is a question which contains a controversial or unjustified assumption (e.g., a presumption of guilt).[1]

Aside from being an informal fallacy depending on usage, such questions may be used as a rhetorical tool: the question attempts to limit direct replies to be those that serve the questioner's agenda.[2] The traditional example is the question "Have you stopped beating your wife?" Whether the respondent answers yes or no, he will admit to having a wife and having beaten her at some time in the past. Thus, these facts are presupposed by the question, and in this case an entrapment, because it narrows the respondent to a single answer, and the fallacy of many questions has been committed.[2] The fallacy relies upon context for its effect: the fact that a question presupposes something does not in itself make the question fallacious. Only when some of these presuppositions are not necessarily agreed to by the person who is asked the question does the argument containing them become fallacious.[2] Hence the same question may be loaded in one context, but not in the other. For example the previous question would not be loaded if it was asked during a trial in which the defendant has already admitted to beating his wife.[2]

This fallacy should be distinguished from that of begging the question,[3] which offers a premise whose plausibility depends on the truth of the proposition asked about, and which is often an implicit restatement of the proposition.[4]

The term "loaded question" is sometimes used to refer to loaded language that is phrased as a question. This type of question does not necessarily contain a fallacious presupposition, but rather this usage refers to the question having an unspoken and often emotive implication. For example, "Are you a murderer?" would be such a loaded question, as "murder" has a very negative connotation. Such a question may be asked merely to harass or upset the respondent with no intention of listening to their reply, or asked with the full expectation that the respondent will predictably deny it.

Thursday, April 10, 2014

Logical Fallacy #9 - Special Pleading


Wikipedia: Special pleading (also known as stacking the deck, ignoring the counterevidence, slanting, and one-sided assessment[1]) is a form of spurious argument where a position in a dispute introduces favourable details or excludes unfavourable details by alleging a need to apply additional considerations without proper criticism of these considerations. Essentially, this involves someone attempting to cite something as an exception to a generally accepted rule, principle, etc. without justifying the exception.[2]

The lack of criticism may be a simple oversight (e.g., a reference to common sense) or an application of a double standard.

A more difficult case is when a possible criticism is made relatively immune to investigation. This immunity may take the forms of:
--unexplained claims of exemption from principles commonly thought relevant to the subject matter. Example: I'm not relying on faith in small probabilities here. These are slot machines, not roulette wheels. They are different.
--claims to data that are inherently unverifiable, perhaps because too remote or impossible to define clearly. Example: Cocaine use should be legal. Like all drugs, it does have some adverse health effects, but cocaine is different from other drugs. Many have benefited from the effects of cocaine.

In the classic distinction among informal (material), psychological, and formal (logical) fallacies, special pleading most likely falls within the category of psychological fallacy, as it would seem to relate to "lip service", rationalization and diversion (abandonment of discussion). Special pleading also often resembles the "appeal to" logical fallacies.[3]

In medieval philosophy, it was not assumed that wherever a distinction is claimed, a relevant basis for the distinction should exist and be substantiated. Special pleading subverts an assumption of existential import.

Friday, April 04, 2014

Logical Fallacy #8 - Personal Incredulity


A form of Argument from Ignorance:
Arguments from incredulity take the form:
P is too incredible (or: I cannot imagine how P could possibly be true); therefore P must be false.
I cannot imagine how P could possibly be false; therefore P must be true.
These arguments are similar to arguments from ignorance in that they too ignore and do not properly eliminate the possibility that something can be both incredible and still be true, or appear to be obvious and yet still be false.

Thursday, March 27, 2014

Logical Fallacy #7: Tu Quoque


Tu quoque /tˈkwkw/,[1] (Latin for "you, too" or "you, also") or the appeal to hypocrisy, is a logical fallacy that attempts to discredit the opponent's position by asserting the opponent's failure to act consistently in accordance with that position; it attempts to show that a criticism or objection applies equally to the person making it. This dismisses someone's point of view based on criticism of the person's inconsistency and not the position presented[2] whereas a person's inconsistency should not discredit the position. Thus, it is a form of the ad hominem argument.[3] To clarify, although the person being attacked might indeed be acting inconsistently or hypocritically, such behavior does not invalidate the position presented.

Saturday, March 22, 2014

Logical Fallacy #6 - Ad Hominem


Per Wikipedia:

An ad hominem (Latin for "to the man" or "to the person"[1]), short for argumentum ad hominem, is a general category of fallacies in which a claim or argument is rejected on the basis of some irrelevant fact about the author of or the person presenting the claim or argument.[2] Fallacious Ad hominem reasoning is normally categorized as an informal fallacy,[3][4][5] more precisely as a genetic fallacy,[6] a subcategory of fallacies of irrelevance.[7] Ad hominem reasoning is not always fallacious, for example, when it relates to the credibility of statements of fact.

Ad hominem arguments are the converse of appeals to authority, and may be used in response to such appeals.

Thursday, March 13, 2014

Logical Fallacy #5: The Slippery Slope





Per Wikipedia:
In logic and critical thinking, a slippery slope is a logical device, but is usually known under its fallacious form in which a person asserts that some event must inevitably follow from another without any rational argument or demonstrable mechanism for the inevitability of the event in question. A slippery slope argument states that a relatively small first step leads to a chain of related eventsculminating in some significant effect, much like an object given a small push over the edge of a slope sliding all the way to the bottom.[1] The strength of such an argument depends on the warrant, i.e. whether or not one can demonstrate a process which leads to the significant effect. The fallacious sense of "slippery slope" is often used synonymously with continuum fallacy, in that it ignores the possibility of middle ground and assumes a discrete transition from category A to category B. Modern usage avoids the fallacy by acknowledging the possibility of this middle ground.
The argument takes on one of various semantical forms:In the classical form, the arguer suggests that making a move in a particular direction starts something on a path down a "slippery slope". Having started down the metaphorical slope, it will continue to slide in the same direction (the arguer usually sees the direction as a negative direction, hence the "sliding downwards" metaphor).
Modern usage includes a logically valid form, in which a minor action causes a significant impact through a long chain of logical relationships. Note that establishing this chain of logical implication (or quantifying the relevant probabilities) makes this form logically valid. The slippery slope argument remains a fallacy if such a chain is not established.

Thursday, March 06, 2014

Logical Fallacy # 4: The Fallacy Fallacy


From Wikipedia:
Argument from fallacy is the formal fallacy of analyzing an argument and inferring that, since it contains a fallacy, its conclusion must be false.[1] It is also called argument to logic (argumentum ad logicam), fallacy fallacy,[2] fallacist's fallacy,[3] and bad reasons fallacy.[4]
Fallacious arguments can arrive at true conclusions, so this is an informal fallacy of relevance.[5]
Form[edit]:
It has the general argument form:
If P, then Q.
P is a fallacious argument.
Therefore, Q is false.[6]
Thus, it is a special case of denying the antecedent where the antecedent, rather than being a proposition that is false, is an entire argument that is fallacious. A fallacious argument, just as with a false antecedent, can still have a consequent that happens to be true. The fallacy is in concluding the consequent of a fallacious argument has to be false.
That the argument is fallacious only means that the argument cannot succeed in proving its consequent.[7] But showing how one argument in a complex thesis is fallaciously reasoned does not necessarily invalidate the proof; the complete proof could still logically imply its conclusion if that conclusion is not dependent on the fallacy:

All great historical and philosophical arguments have probably been fallacious in some respect... If the argument is a single chain, and one link fails, the chain itself fails with it. But most historians' arguments are not single chains. They are rather like a kind of chain mail which can fail in some part and still retain its shape and function.  --David Hackett Fischer, Historians' fallacies[3]

Thursday, February 27, 2014

Logical Fallacy #3 - Appeal To Emotion



Appeal to emotion (or argumentum ad passiones) is a logical fallacy which uses the manipulation of the recipient's emotions, rather than valid logic, to win an argument. The appeal to emotion fallacy uses emotions as the basis of an argument's position without factual evidence that logically supports the major ideas endorsed by the elicitor of the argument. Also, this kind of thinking may be evident in one who lets emotions and/or other subjective considerations influence one's reasoning process. This kind of appeal to emotion is a type of red herring and encompasses several logical fallacies, including:
Appeal to consequences
Appeal to fear
Appeal to flattery
Appeal to pity
Appeal to ridicule
Appeal to spite
Wishful thinking

Thursday, February 20, 2014

Logical Fallacy #2 - False Cause




There's a good number of sub-headings under False Cause (aka: Questionable Cause).
I grabbed this one from Wikipedia just cuz it's my fave:
Post hoc ergo propter hoc (Latin: "after this, therefore because of this") is a logical fallacy (of the questionable cause variety) that states "Since event Y followed event X, event Y must have been caused by event X." It is often shortened to simply post hoc. It is subtly different from the fallacy cum hoc ergo propter hoc (correlation does not imply causation), in which two things or events occur simultaneously or the chronological ordering is insignificant or unknown. Post hoc is a particularly tempting error because temporal sequence appears to be integral to causality. The fallacy lies in coming to a conclusion based solely on the order of events, rather than taking into account other factors that might rule out the connection.

Thursday, February 13, 2014

Logical Fallacy #1 - Straw Man


From Wikipedia:
The straw man fallacy occurs in the following pattern of argument:
  1. Person 1 has position X.
  2. Person 2 disregards certain key points of X and instead presents the superficially similar position Y. The position Y is a distorted version of X and can be set up in several ways, including:
    1. Presenting a misrepresentation of the opponent's position.
    2. Quoting an opponent's words out of context—i.e., choosing quotations that misrepresent the opponent's actual intentions (see fallacy of quoting out of context).[4]
    3. Presenting someone who defends a position poorly as the defender, then denying that person's arguments—thus giving the appearance that every upholder of that position (and thus the position itself) has been defeated.[3]
    4. Inventing a fictitious persona with actions or beliefs which are then criticized, implying that the person represents a group of whom the speaker is critical.
    5. Oversimplifying an opponent's argument, then attacking this oversimplified version.
  3. Person 2 attacks position Y, concluding that X is false/incorrect/flawed.
This reasoning is fallacious because attacking a distorted version of a position does not address the actual position. The ostensible argument that Person 2 makes has the form:
"Don't support X, because X has an unacceptable (or absurd or contradictory or terrible) consequence."
However, the actual form of the argument is:
"Don't support X, because Y has an unacceptable (or absurd or contradictory or terrible) consequence."
This argument doesn't make sense; it is a non sequitur. Person 2 relies on the audience not noticing this.