logic unit 1 exam
Tu Quoque
"you also..." hypocrisy
what is an unsound argument
An argument that is either invalid or has a false premise or both
if a, then b if b then c if a then c
Hypothetical Syllogism
The sky is blue. The sky is cobalt blue only if it is blue. So, The sky is cobalt blue.
Invalid (affirming the consequent)
if a then b not b not a
Modus Tollens
The state cannot uphold the value of life by taking it. And if the state cannot uphold the value of life by taking it, then the death penalty should be abolished. So, the death penalty should be abolished.
Valid (modus ponens)
what is a cogent argument
a strong argument with true premises
what is a sound argument
a valid argument with all true premises
if a then b b a
affirming the consequent
ad hominem
against the person
begging the question
already assuming the truth of the point to be proved
what is an uncogent argument
an argument that is either strong with at least one false premise or weak
Ad ignorantiam
appeal to ignorance
Ad Misericordiam
appeal to misery/pity
ad baculum
appeal to power threat
Nowadays, everybody who is anybody knows that CrossFit is the coolest way to keep fit.
appeal to the people
As populum
appeal to the people/agree with the crowd
Getting good grades in college is like getting a plentiful crop from a garden. Dailyattention is required to produce a strong harvest from a garden. Just so, daily work isthe key to good grades in college.
argument from analogy
Having an abortion is like using contraception. In both cases, the intent is the same: toavoid having a baby. And plainly, contraception is morally permissible. Thus, abortion ismorally permissible also.
argument from analogy
Actor Tom Hanks stated that as many as 12,000 Allied forces died as a result of theD-Day invasion during World War II. So as many as 12,000 Allied forces died as a result of D-Day.
argument from authority
The word "obviate" means "to do away with or prevent" because that is what Webster'sDictionary says it means.
argument from authority
false cause
assuming some cause when no good reason exists for eliminating other possibly causes
slippery slope
changes topics
circumstantial
compromising circumstance
ambiguity
conceptual or interpretive confusion between terms or concepts
either a or b if a then c if b then d either c or d
constructive dilemma
Either the "eye for an eye" principle is interpreted literally or it is interpreted figuratively.If it is interpreted literally, then the state should torture torturers, maim maimers, andrape rapists. If the "eye for an eye" principle is interpreted figuratively, then it does notnecessarily demand death for murderers. So, either the state should torture torturers,maim maimers, and rape rapists, or the "eye for an eye" principle does not necessarilydemand death for murderers.
constructive dillema
if a then b not a not b
denying the antecedent
if a, then b not a not b
denying the antecedent
either a or b not a b
disjunctive syllogism
amphiboly
double meaning for grammatical reasons
Scientists have shown that a person loses a very small but measurable amount of weight at the time of death. This weight loss is probably due to the soul's leaving the body at that time. What else could account for this phenomenon? Here we have unexpected scientific evidence for the existence of an immaterial soul.
false clause
If you study hard, you refine your communication skills. If you refine yourcommunication skills, then your job opportunities increase. Hence, if you study hard,your job opportunities increase.
hypothetical syllogism
what is a valid argument
if all the premises are true, the conclusion must also be true.
What is a weak argument?
if premises are true then conclusion has a low probability of being true
what is a strong argument
if premises are true, then conclusion has a high probability of being true
complex question
illegitimately assuming a conclusion suggested
straw man
intentional misrepresentation
complex question
introduces irrelevant facts, long.
If I have the flu then I'll have a fever. I have a fever. Therefore, I have the flu.
invalid affirming the concequent
This lovely china plate is similar in size, weight, and composition to the one I justdropped. The one I just dropped broke. So, if I drop this lovely china plate, it will break.
invalid and strong
A porpoise is similar to a human being. It has lungs rather than gills. It is warm-bloodedrather than cold-blooded. And porpoises nurse their young with milk. Therefore,porpoises, like humans, are capable of speaking languages.
invalid and weak
No circles are squares. All circles are figures. So, no figures are squares.
invalid and weak
Eating meat is unhealthy if meat contains a lot of cholesterol. Meat does contain a lot ofcholesterol. So, eating meat is unhealthy.
modus ponens
if a then b a so b
modus ponens
Overeating is foolish only if it causes disease. Overeating does not cause disease. So,overeating is not foolish.
modus tollens
Global oil demand still lies well below the peak level of 1979. Improved energy efficiency and the expanding role of natural gas in many countries is cutting into petroleum's market. But oil is still the world's leading source of energy, supplying 40 percent of the total . . . . --Christopher Flavin and Hal Kane, "Oil Production Steady" in Lester Brown, Hal Kane, Ed Ayres, Vital Signs 1993: The Trends That Are Shaping Our Future (New York: W. W. Norton, 1993), p. 46.
not an argument
If corporations are people, then corporations have the right to marry.
not an argument
U. S. food producers feed livestock 20 million tons of plant protein per year that could be consumed by humans, and the livestock yields only two million tons of protein.
not an argument
We [Americans] had roughly ten thousand handgun deaths last year. The British had forty. In 1978, there were 18,714 Americans murdered. Sixty four percent were killed with handguns. In that same year, we had more killings with handguns by children ten years old and younger than the British had by killers of all ages. The Canadians had 579 homicides last year; we had more than twenty thousand.
not an argument
red herring
not extremist, just changed the subject to something arguable
composition
part/ whole issues
Approximately 60% of college students do not engage in binge drinking. Maria is acollege student. So, Maria does not engage in binge drinking.
statistical syllogism
82% of democrats are supporters of abortion rights. Senator Casey is a democrat. So,Senator Casey is a supporter of abortion rights.
statstical syllogism
straw man argument
stays on the same topic
All observed emeralds have been green. So, the next emerald to be observed will begreen.
strong
What is an invalid argument?
the premises can be true but have a false conclusion
false dillema
using a premise that unjustifiably reduced the number of alternatives or options to be considered
It is not wrong to kill spiders. But if spiders have eternal souls, then it is wrong to kill them. Thus, it is false that spiders have eternal souls.
valid (modus tollens)
Every serial killer is a psychopath. Some criminals are not psychopaths. So, somecriminals are not serial killers.
valid (unsound)
abusive
verbal attack
equivocation
when a term has more than one meaning, undermining validity
division
whole/ part issue
