logic 1st part reviewer

8/10/2019 Logic 1st Part Reviewer

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Logic- study of the methods and principles used to distinguish correct and incorrect reasoning.

Arguments- built with propositons

Propositions- building blocks of reasoning, asserts that something is the case.

Conjunctive proposition- equivalent go asserting each of its component propositions separately.

Compound propositions- do not assert fhe truth of their components.

Disjunctive- no one of their components is asserted.

Arguments- affirm one proposition the basis of some other propositions.

Refers strictly to a group of propositons of which one is claimed to follow from the others, which provides

support for the truth of that one.

Inference- process that may gie together a clusternof propositions.

Conclusion- propostion that is affirmed on the basis of the other propositions of the argument.

Premises- affirmed as providing support for the conclusion.

Deductive- makes a claim that its conclusion is supported by premises conclusively, conclusiveness is made.

Deals with validity, valid when if its premises are true, its conclusion must be true. If already valid, no additional

premise can possibly add to the strength of that argument.

Conclusion is claimed to follow from its premises with absolute necessity, this necessity not being a matter of

degree and not depending in any way on whatever is the case.

Inductive- does not make a claim of conclusiveness. Conclusion is claimed to follow from its premises only with

probability, being a matter of degree and dependent on what else may be tge case.

May be weak or strong, additional information may strengthen or weaken it.

Validity/invalidity- refers to the relation between its propositons. Attributes of arguments

Truth/falsity- attribute of a proposition that asserts what really is the case. Attributes of individual propositions or

statements.

Fallacy-any error in reasoning, incorrect argument.

Formal fallacy-it is a pattern of mistake that appears in deductive arguments of a certain specificable form.

Fallacies of relevance

They arise when there is no real connection between the premises and the conclusion of an argument.

APPEAL TO EMOTION (ARGUMENTUM AD POPULUM)-instead of evidence and rational argument, the speaker relies on

expressive language and other devices calculated to excite enthusiasm for or against some cause. (Ex. Bandwagon

fallacy)

support offered is for some conclusion that is an iappropriate appeal to the emotions


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RED HERRING- distraction, attention is deflected; readers or listeners are drawn to some aspect of the topic under

discussion by which they are led away from the issue that had been the focus of the discussion.

Deliberately misleading trail.

Committed when some distraction is used to mislead and confuse.

STRAW MAN- also introduces a distraction to the real dispute. It is an effort to shift the conflict from its original

complexity into a different conflict, between parties oher than those originally in dispute. It adopts the most extremeview possible, every kind is to be rejected, it is aimed at a new irrelevant target.

Committed when the position of one's opponent is misrepresented and that position is made the object of the

attack.

ARGUMENT AGAINST THE PERSON (AD HOMINEM)-thrust is not directed, not at a conclusion bjt at some persom who

defends the conclusion in dispute; a personalized attack.

Rather than attacking the substance of some position, one attacks the person of its advocate, either abusively or

as a consequence of his or her special circumstance.

Is the attack on the perkson relevant to the truth of what is at issue, if not it is fallacious.

AD HOMINEM, ABUSIVE- to disparage the character of one's opponents, to deny their intelligence or reasonableness, to

question their understanding, or their seriousness or even their integrity.

EX. Opponent may be reviled because he is of a certain religious or political persuasion. Attacking the source.

AD HOMINEM, CIRCUMSTANTIAL (LOOK WHO'S TALKING)

the circumstances of o e who makes or rejects some claim have no more bearing on the truth of what is claimed,

than does his character. The mistake treats those personal circumstances as the premise of an opposing

argument. Argument is irrelevant to the proposition in question;it simply urges that person's circumstances

require its acceptance.

Ex. Hunters are criticized for killing for amusement and responds that their criticts are meat eaters.- does not

prove that it is right for them to kill animals for amusement.

APPEAL TO FORCE (ARGUMENT AD BACULUM)- threats or strong-arm methods are used to coerce opponents. It can

hardly be consodered as arguments at all.

EX. Veiled threats

MISSING THE POINT (IGNORANTIA ELENCHI)-there is a disconnect between the premises and the conclusion. Mayresult from deception or sloppy thinking. Mistake is made that is made in seeking to refute another's argument.

one refutes, not the thesis one's inlocutor is advancing, but some different thesis that one mistakenly imputes to

him or her.

FALLACIES OF DEFECTIVE INDUCTION- premises of the fallacious argument are not relevant to the conclusions

drawn.

What are asserted as premises simply do not serve as good reasons to reach the conclusion drawn.

THE ARGUMENT FROM IGNORANCE (ARGUMENT AD IGNORANTIAM)- plausible claims are held to be false becauseevidence of their truth cannot be provided.

Ex. No (evidence), there isnt. There really isnt, but there is no evidence to the contrary either.


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THE APPEAL TO INAPPROPRIATE AUTHORITY (ARGUMENT AD VERECUNDIAM)- arises when the appeal is made to

parties who have no legitimate claim to authority in the matter at hand.

Whenever the truth of some proposition is asserted on the basis of the authority of one who has no special

competence in that sphere, the appeal to inappropriate authority is the fallacy committed.

FALSE CAUSE (ARGUMENT NON CAUSA PRO CAUSA)-presuming that reality of a casual connection that does not really

exist is a common mistake.

One treats of a thing that which is not really the cause of that thing, often relying merely on the close temporal

succession of two events.

We mistakenly presume that one event is caused by another because it follows that other closely in time.

Ex. post hoc ergo propter hoc- after the thing, therefore because of the thing

Also committed when one mistakenly argues against some proposal on the ground that any change in a given

direction is sure to lead to further changes in the same direction-and thus to grave consequences.

HASTY GENERALIZATION- committed when we draw conclusions about all the persons or things in a given class on the

basis of our knowledge about all the persons or things in a given class on the basis of our knowledge about only one or

only a very few of the members of that class. Ex. stereotyping

When one moves carelessly or too quickly from one or a very few instances to a broad or universal claim.

FALLACIES OF PRESUMPTION- people may be led to assume the truth of an unproved and unwarranted

proposition. The mistake in argument arises from relying on some proposition that is assumed to be true but is without

warrant and is false or dubious.

ACCIDENT- arises when we move carelessly or unjustifiably from a generalization to some particulars that it does not in

fact cover. Ex: a rule applies universally

One mistakenly applies a generalization to an individual case that it does not properly govern

COMPLEX QUESTION- the question itself is likely to be rhetorical, with no answer actually being sought.

When one argues by asking a question in such a way as to presuppose the truth of some assumption buried in

that question

BEGGING THE QUESTION (PETITIO PRINCIPII)-mistake of assuming the truth of what one seeks to prove. Arguments are

circular- every petition is a circular argument- but the circle that has been constructed may be large and confusing, and

thus the logical mistake goes unseen.

To assume the conclusion sought.

When one assumes in the premises of an argument the truth of what one seeks to establish in the conclusion of

that same argument.

FALLACIES OF AMBIGUITY- words or phrases may shift as a result of inattention, or may be deliberately

manipulated within the course of an argument. A term may have one sense in a premise but quite a different sense in

the conclusion

EQUIVOCATION- more than one literal meaning, arises when the misuse of relative terms, which have different

meanings in different contexts.

Two or more meanings of the same word or phrase has been confused.


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AMPHIBOLY- occurs when one is arguing from premises whose formulations are ambiguous because of their

grammatical construction.

Meaning is indeterminate because of the loose or awkward way in which words are combined. May be true in

one but may be false in another.

Arising from loose, awkward, or mistaken way in which words are combined, leading to alternative possible

meanings of a statement.

ACCENT- words are emphasized differently, distortion of pulling a quoted message out of its context and putting it in

another context.

An informal fallacy committed when a term or phrase has a meaning in the conclusion of an argument different

from its meaning in one of the premises, the difference arising chiefly from a change in emphasis given to the

words used.

COMPOSITION- an inference is mistakenly drawn from the attributes of the parts of a whole to the attributes of the

whole itself.

a)

When one reasons mistakenly from the attributes of a part of the attributes of the whole

b)

When one reasons mistakenly from the attributes of an individual member of some collection to the

attributes of the totality of that collection

DIVISION- a mistaken inference is drawn from attributes of a whole to the attributes of the parts of the whole.

a)

When one mistakenly from the attributes of a whole to the attributes of one of its parts

b)

When one reasons mistakenly from the attributes of a totality of some collection of entities to the attributes

of the individual entities within that collection.

THEORY OF DEDUCTION

Aims to explain the relations of premises and conclusion in valid arguments. It also aims to provide techniques for the

appraisal of deductive arguments, that is for discriminating between valid and invalid deductions.

Deductive argument is one whose premises are claimed to provide conclusive grounds for the truth of its conclusion.

Classes of Categorical Propositions

Deals mainly with the relations of classes of objects to one another.

Class- a collection of all objects that have some specified characteristic in common.

1.

All of one class may be included in all of another class- wholly included/contained

2.

Some, but not all of the members of one class may be included in another class- partially included/contained.

3.

Two classes may have no members in common- exclude one another.

Four Kinds of Categorical Propositions

1.

Universal affirmative- asserts that the whole of one class is included or contained in another class.

Affirms the relation of class inclusion holds between the two classes and says that the inclusion is complete, oruniversal.


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All S is P

2.

Universal negative- asserts that the subject class, is wholly excluded from the predicate class.

No S is P

Denies the relation of inclusion between the two terms and denies it universally.

3. Particular affirmative-some members of the class of all politicians are members of the class of all liars.

Some- at least one

Some S is P

4.

Particular negative- at least one member of the class designated by the subject term is excluded from the whole

of the class designated by the predicate term. The denial is not universal.

Quality- Affirmative or Negative

Quantity- All or Some

Copula- not, are verb that connects the subject and predicate terms.

Distribution- a proposition distributes a term if it refers to all members of the class designated by that term.

A-

Subject is distributed, but the predicate is undistributed.

E- Distribute both their subject and predicate terms

I both subject and predicate terms are not distributed

O subject is not distributed but the predicate term is distributed

Universal (A,E)- dist. Their subject terms

Particular (I,O)- do not dist their subject terms

Affirmative (A,I)- do not dist. Their predicate terms

Negative- distribute their predicate terms

logic 1st part reviewer

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