Logical Falacies

[steve_bank]

Logical Falacies

In reasoning deriving a sound argument and being able to see falacies intentional or not are equallymimportant.

We see politicians on TV today reworting to fallcies. False equivalence and dichotomy. Rattling off a complicated set iof facts unrelated to an arguent that are hard to trac then declaring a conclusion.

The list of informal falcies is too long to post. Many I have never heard of.
https://en.wikipedia.org/wiki/List_of_fallacies
In reasoning to argue a claim, a fallacy is reasoning that is evaluated as logically incorrect and that undermines the logical validity of the argument and permits its recognition as unsound. Regardless of their soundness, all registers and manners of speech can demonstrate fallacies.

Because of their variety of structure and application, fallacies are challenging to classify so as to satisfy all practitioners. Fallacies can be classified strictly by either their structure or content, such as classifying them as formal fallacies or informal fallacies, respectively. The classification of informal fallacies may be subdivided into categories such as linguistic, relevance through omission, relevance through intrusion, and relevance through presumption.[1] On the other hand, fallacies may be classified by the process by which they occur, such as material fallacies (content), verbal fallacies (linguistic), and again formal fallacies (error in inference). In turn, material fallacies may be placed into the more general category of informal fallacies, while formal fallacies may be clearly placed into the more precise category of logical (deductive) fallacies.[clarification needed] Yet, verbal fallacies may be placed into either informal or deductive classifications; compare equivocation which is a word or phrase based ambiguity, e. g. "he is mad", which may refer to either him being angry or clinically insane, to the fallacy of composition which is premise and inference based ambiguity, e. g. "this must be a good basketball team because each of its members is an outstanding player".[2]

The conscious or habitual use of fallacies as rhetorical devices is prevalent in the desire to persuade when the focus is more on communication and eliciting common agreement rather than on the correctness of the reasoning. The effective use of a fallacy by an orator may be considered clever, but by the same token, the reasoning of that orator should be recognized as unsound, and thus the orator's claim, supported by an unsound argument, will be regarded as unfounded and dismissed.[3]
Formal syllogistic fallacies[edit]

Syllogistic fallacies – logical fallacies that occur in syllogisms.
Affirmative conclusion from a negative premise (illicit negative) – a categorical syllogism has a positive conclusion, but at least one negative premise.[12]
Fallacy of exclusive premises – a categorical syllogism that is invalid because both of its premises are negative.[12]
Fallacy of four terms (quaternio terminorum) – a categorical syllogism that has four terms.[13]
Illicit major – a categorical syllogism that is invalid because its major term is not distributed in the major premise but distributed in the conclusion.[12]
Illicit minor – a categorical syllogism that is invalid because its minor term is not distributed in the minor premise but distributed in the conclusion.[12]
Negative conclusion from affirmative premises (illicit affirmative) – a categorical syllogism has a negative conclusion but affirmative premises.[12]
Fallacy of the undistributed middle – the middle term in a categorical syllogism is not distributed.[14]
Modal fallacy – confusing possibility with necessity.

 

[steve_bank]

False Dichotomy

False dichotomy is routuinely used by politians. An agrgu ent crafted to disparge an issue by slective comparisons. A good example is the conservative arguments against Medicare fot=r all. Selective comparison to some aspects of Canadian socilized medicine. Canadians have to wait months in some cases for routine non critical surgery, therefore Medicare for all will result in Americans not getting care.

https://en.wikipedia.org/wiki/Dichotomy

A dichotomy /daɪˈkɒtəmi/ is a partition of a whole (or a set) into two parts (subsets). In other words, this couple of parts must be jointly exhaustive: everything must belong to one part or the other, and
mutually exclusive: nothing can belong simultaneously to both parts.

Such a partition is also frequently called a bipartition.

The two parts thus formed are complements. In logic, the partitions are opposites if there exists a proposition such that it holds over one and not the other.

Treating continuous variables or multicategorical variables as binary variables is called dichotomization. The discretization error inherent in dichotomization is temporarily ignored for modeling purposes.

Usage and examples[edit]
The above applies directly when the term is used in mathematics, philosophy, literature, or linguistics. For example, if there is a concept A, and it is split into parts B and not-B, then the parts form a dichotomy: they are mutually exclusive, since no part of B is contained in not-B and vice versa, and they are jointly exhaustive, since they cover all of A, and together again give A.

A false dichotomy is an informal fallacy consisting of a supposed dichotomy which fails one or both of the conditions: it is not jointly exhaustive and/or not mutually exclusive. In its most common form, two entities are presented as if they are exhaustive, when in fact other alternatives are possible. In some cases, they may be presented as if they are mutually exclusive although there is a broad middle ground (see also undistributed middle).

 

[steve_bank]

Circular Reasonung

p1 a is true if b is true
p2 b is true if a is true
c A and B are both true.

On the face of it the conclusion may seem valid, but there is no independent truth of either p1 and p2.

The theist argument

p1 god exists because god is in the bible
p2 the bible is true because god inspired it
c the bible is true and god exists.

If you watch politics long enough you will see it in action. Sometimes by intent and sometimes from ignorance.

https://en.wikipedia.org/wiki/Circular_reasoning


Circular reasoning


Circular reasoning (Latin: circulus in probando, "circle in proving";[1] also known as circular logic) is a logical fallacy in which the reasoner begins with what they are trying to end with.[2] The components of a circular argument are often logically valid because if the premises are true, the conclusion must be true. Circular reasoning is not a formal logical fallacy but a pragmatic defect in an argument whereby the premises are just as much in need of proof or evidence as the conclusion, and as a consequence the argument fails to persuade. Other ways to express this are that there is no reason to accept the premises unless one already believes the conclusion, or that the premises provide no independent ground or evidence for the conclusion.[3] Begging the question is closely related to circular reasoning, and in modern usage the two generally refer to the same thing.[4]

Circular reasoning is often of the form: "A is true because B is true; B is true because A is true." Circularity can be difficult to detect if it involves a longer chain of propositions. Academic Douglas Walton used the following example of a fallacious circular argument: