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Premise, Inference, Conclusion

December 8th, 2013 No comments

Premise

One or more propositions are necessary for the argument to continue. They must be stated explicitly. They are called the premises of the argument. They are the evidence (or reasons) for accepting the argument and its conclusions.

Premises (or assertions) are often indicated by phrases such as “because”, “since”, “obviously” and so on.

(The phrase “obviously” is often viewed with suspicion, as it can be used to intimidate others into accepting dubious premises. If something doesn’t seem obvious to you, don’t be afraid to question it. You can always say “Oh, yes, you’re right, it is obvious” when you’ve heard the explanation.)

 

Inference

The premises of the argument are used to obtain further propositions. This process is known as inference. In inference, we start with one or more propositions which have been accepted. We then derive a new proposition. There are various forms of valid inference.

The propositions arrived at by inference may then be used in further inference. Inference is often denoted by phrases such as “implies that” or “therefore”.

 

Conclusion

Finally, we arrive at the conclusion of the argument, another proposition. The conclusion is often stated as the final stage of inference. It is affirmed on the basis the original premises, and the inference from them. Conclusions are often indicated by phrases such as “therefore”, “it follows that”, “we conclude” and so on.

Categories: Logic

False Dilemma – Expanded

June 1st, 2010 No comments

-A Hobson’s choice is a free choice in which only one option is offered. As a person may refuse to take that option, the choice is therefore between taking the option or not; “take it or leave it”. The phrase is said to originate from Thomas Hobson (1544–1631), a livery stable owner at Cambridge, England. To rotate the use of his horses he offered customers the choice of either taking the horse in the stall nearest the door or taking none at all.

-An apparently free choice that offers no real alternative.

-No real choice at all – the only options being to either accept or refuse the offer that is given to you.

The Spectator, No. 509, 1712, explains how Hobson did business, which shows clearly how the phrase came into being: “He lived in Cambridge, and observing that the Scholars rid hard, his manner was to keep a large Stable of Horses, … when a Man came for a Horse, he was led into the Stable, where there was great Choice, but he obliged him to take the Horse which stood next to the Stable-Door; so that every Customer was alike well served according.”

The most celebrated application of Hobson’s choice in the 20th century was Henry Ford’s offer of the Model-T Ford in ‘any color you like, so long as it’s black’.

Categories: Logic

Fallacy Of Accent – Expanded

April 6th, 2010 No comments

Aristotle maintained that an argument depending upon accent it is not easy to construct in unwritten discussion; in written discussions and in poetry it is easier. ((Aristotle. On Sophistical Refutations trans. W. A. Pickard-Cambridge (eBooks@Adelaide) (The University of Adelaide Library, University of Adelaide South Australia), Part 4.))Thus (e.g.) some people emend Homer against those who criticize as unnatural his expression to men ou kataputhetai ombro. For they solve the difficulty by a change of accent, pronouncing the ou with an acuter accent. Also, in the passage about Agamemnon’s dream, they say that Zeus did not himself say ‘We grant him the fulfillment of his prayer’, but that he bade the dream grant it. Instances such as these, then, turn upon the accentuation.

Others come about owing to the form of expression used, when what is really different is expressed in the same form, e.g. a masculine thing by a feminine termination, or a feminine thing by a masculine, or a neuter by either a masculine or a feminine; or, again, when a quality is expressed by a termination proper to quantity or vice versa, or what is active by a passive word, or a state by an active word, and so forth with the other divisions previously’ laid down. For it is possible to use an expression to denote what does not belong to the class of actions at all as though it did so belong. Thus (e.g.) ‘flourishing’ is a word which in the form of its expression is like ‘cutting’ or ‘building’: yet the one denotes a certain quality-i.e. a certain condition-while the other denotes a certain action. In the same manner also in the other instances.

According to Copi and Cohen ((Irving M. Copi & Carl Cohen, Introduction to Logic (Twelfth Edition) (Prentice Hall, 2005), pp. 156-158.))An argument may prove deceptive, and invalid, when the shift of meaning within it arises from changes in the emphasis given to its words or parts. When a premise relies for its apparent meaning on the one possible emphasis, but a conclusion is drawn from it that relies on the meaning of the same words accented differently, the fallacy of accent is committed.
Consider, as illustration, the different meanings that can be given to the statement:
We should not speak ill of our friends.
At least five distinct meanings-or more?-can be given to those eight words, depending on which one of them is emphasized.

Categories: Logic

Fallacy of False Attribution

December 12th, 2009 No comments

Taxonomy – Where am I?

Fallacy of False Attribution

classification : informal – fallacies of ambiguity – equivocation

Occurs when an advocate appeals to an irrelevant, unqualified, unidentified, biased or fabricated source in support of an argument.

Examples

“Objectivism advocates infanticide, therefore Objectivism is evil.”

Foundations

Present a false description of your adversary and then base your repudiation on that description.

Other Names

Equivocation
Fallacy of quoting out of context
Loki’s Wager
No true Scotsman
Reification
Matthew effect ( “accumulated advantage” )
Begging The Question

Categories: Logic

Fallacy of Inconsistency

December 12th, 2009 No comments

Taxonomy – Where am I?

Fallacy of Inconsistency

classification : informal – non sequitur

Where something inconsistent, self-contradictory or self-defeating is presented.

Examples
Yogi Berra quote: “Baseball is 90 percent mental. The other half is physical.”

Foundations

Asserts more than one proposition such that the propositions cannot all be true. Arguing from inconsistent statements, or to conclusions that are inconsistent with the premises.

Other Names

tu quoque

Categories: Logic

Denying The Antecedent

December 12th, 2009 No comments

Taxonomy – Where am I?

Denying The Antecedent

classification : formal – fallacy of propositional Logic

Arguments of this form do not give good reason to establish their conclusions, even if their premises are true.

Foundations

When a premise of an argument denies the truth of the antecedent of a conditional premise, then concludes by denying the truth of the conditional premises’ consequent.

Other Names

Same Category: Affirming the Consequent

Categories: Logic

Appeal To Consequences

November 29th, 2009 No comments

Taxonomy – Where am I?

Appeal To Consequences (argumentum ad consequentiam)

classification : informal – appeals to motives in place of support

An argument that concludes a premise (typically a belief) to be either true or false based on whether the premise leads to desirable or undesirable consequences.

Foundations

Based on an appeal to emotion since the desirability of a consequence does not address the truth value of the premise. Moreover, in categorizing consequences as either desirable or undesirable, such arguments inherently contain subjective points of view.

Sub Fallacies

Appeal to Force
Wishful Thinking

Red Herring

Categories: Logic

Quoting Out Of Context

November 29th, 2009 No comments

Taxonomy – Where am I?

Quoting Out Of Context

classification : informal – fallacies of ambiguity

To quote out of context is to remove a passage from its surrounding matter in such a way as to distort its meaning.

Foundations

It is often included with the Fallacy of Accent.  However, Aristotle’s original Fallacy of Accent referred solely to shifting the accent on syllables within words, and it has already be stretched a little to include shifting the accent between words within a sentence. To expand it further is reason the concept of “quoting out of context” gets its own section.

Fallacious quoting can take two distinct forms; Straw Man and Appeal to Authority.

Categories: Logic

Fake Precision Fallacy

November 28th, 2009 No comments

Taxonomy – Where am I?

Fake Precision Fallacy

classification : informal – fallacies of vagueness

Occurs when an argument treats information as more precise than it really is.

Foundations

When imprecise information contained in the premises must be taken as precise in order to adequately support the conclusion.

Examples

Other Names

Fake Precision
False Precision
Misplaced Precision
Spurious Accuracy

Categories: Logic

In A Certain Respect And Simply

November 25th, 2009 No comments

Taxonomy – Where am I?

In A Certain Respect And Simply

classification : informal – Non-sequitur

Take an attribute that is bound to a certain area and assume that it can be applied to a wider domain than was originally intended.

Foundations

When we discuss an attribute of something or somebody, we implicitly assume that there is some constraining contextual factors. When the assumption is carried too far in this context, then this fallacy is committed.

Other Names

Secundum quid et simpliciter

Note: On Sophistical Refutations – Translated by W. A. Pickard-Cambridge

Categories: Logic