Phil

Non-argument - Report of an argument

The attribution of an argument to somebody other than the speaker; the speaker does not
necessarily endorse the argument.

Non-argument - Unsupported assertion

Expressing one’s belief with no intention to support it.
Examples: “People aren’t afraid of dying; they are afraid of not living.”
“People like this course because of the professor.” [In the second example, notice the presence of what looks like a
premise indicator, but no real premise is present

Non-argument - Conditional (if blank then blank) statements

For instance, in the event of rain the picnic will be cancelled. Its cause and effect. If I was taller then I would play basketball.

Non-argument - Illustration

Passages that contain an illustration contain examples of a claim. Many wildflowers are edible. for example, daisies and day lilies are great in a salad.

Non-argument - Explanation

In an explanation, the main claim typically represents an accepted “fact,” and what looks like a premise
or set of premises merely represents a cause of that fact. The purpose of an explanation is to help us understand how
or why that fact occurs (there is no inference in it). Arguments offer evidence while explanations simply state a fact or idea. For instance, the titanic sank because it struck an iceberg. There is no intent to persuade.

Deductive argument 1 that is invalid

Affirming the consequent,

If p then q

q

therefore, p

In reality the fact that q occurs does not mean that p must also have happened to cause it.

Example I told Jake that if he stayed out late partying the night before the calculus final, he would fail the
course. I just heard he failed. It’s clear to me that he did stay out partying.

Answer:
p = Jake stays out late partying the night before the calculus final.
q = Jake fails the exam.

P1. If p then q.
P2. q.
C. Therefore, p.

P1. If Jake stayed out late partying the night before the calculus final, he will fail the course.
P2. He failed the exam.
C. Jake stayed out late partying the night before the calculus final.

Evaluation: Affirming the consequent. Invalid. Jake could well have failed and not have been out
partying. For instance, he might have simply chosen not to study calculus but instead spent the
night reading a book. Or maybe Jake just doesn’t have aptitude for math.

Deductive argument 2 that is invalid

Denying the antecedent

If p then q

not p

therefore not q

The fact that p did not happen does not definitively prove that q must also not happen.

for example If Saddam Hussein was executed by the Americans, he’d be dead. The fact of the matter,
however, is that Saddam Hussein was not executed by the Americans. So, Saddam Hussein is still
alive.

Answer:
p = Saddam Hussein was executed by the Americans
q = Saddam Hussein would be dead

If p then q.
Not p.
Therefore, Not q.

P1. If Saddam Hussein was executed by the Americans, then he would be dead.

P2. It is not the case that Saddam Hussein was executed by the Americans.
C. Therefore, it is false that Saddam Hussein is dead.

Evaluation: Denying the Antecedent. Invalid.

Inductive arguments - Inductive generalization

Z percent of observed F’s are G

It is probable therefore that Z percent of all F’s are G

Example - On April 27th of 2024, at McGill University in Montreal, the Student Union declared a Palestine
Jeans Day. On that day, 83 per cent of the students came to the campus wearing jeans to indicate
their support of Palestinian rights in the Israel-Gaza war. The Student Union concluded that most
university students support Palestinian rights.

Answer: Inductive Generalization
P1. Z per cent of observed Fs are G.
C. It is probable, therefore, that Z per cent of all Fs are G.

Z = 83%
F = Students at McGill University
G = Support for Palestinian rights

P1. 83 % of students at McGill University displayed support for Palestinian rights.
C. It is probable, therefore, most university students support Palestinian rights.

Evaluation: This is an unsuccessful inductive generalization/weak. The conclusion that 83 % of
students support Palestinian rights is not adequately supported by the evidence. The sample is
biased. Jeans are very popular amongst university students, and thus, many students would wear
jeans regardless of the significance. Furthermore, the conclusion that university students in
general support Palestinian rights is faulty as well, as it is an unrepresentative sample, what about
universities in other areas, provinces or countries?

Inductive arguments - Statistical syllogism

Z percent of all F’s are G

X is an F

It is probable to the degree 0.Z therefore that X is G

Example I asked several other students in my Advanced Algebra class what they thought of Professor
Crator's Intro to English Literature last semester. Most of them were really bored with the class. So,
Professor Crator must be a boring teacher. So, I'm sure not going to take her course.

Answer: Statistical Syllogism
P1. Z per cent of all Fs are G.
P2. x is an F.
C. It is probable to the degree 0.Z, therefore, that x is G.

Z = Most of students in my Advanced Algebra class who took Professor Crator’s English Literature
class.
x = I’m enrolled in Professor Crator’s English Literature class.
F = Students who took Professor Crator’s English Literature class.
G = Find the class boring.

P1. Most students in my Advanced Algebra class who took Professor Crator’s English Literature
class found his class really boring.
P2. I’m enrolled in Professor Crator’s class.
C. It’s probably the case that I will find Professor Crator’s English Literature class boring.

Evaluation: This a weak statistical syllogism. This argument attempts to establish either (a) that
Professor Crator’s Intro class is boring or (b) more generally, that she is a really boring teacher. In
regard to (a), the sample size is vaguely stated and probably rather small (“several”) and the
sample is not random, since it is made up of entirely of students in the Advanced Algebra class. The
argument is even weaker if the conclusion is (b). For (b) would apparently mean that all (or at least
most) of Professor Crator’s classes are boring. For this more sweeping claim, the sample size
(whatever it is exactly) is relatively smaller. Depending on how it’s interpreted, this argument could
also be seen as a weak inductive generalization.

Inductive arguments - analogical argument by relations

x is to y as a is to b

x is r to y

It is probable therefore that a is r to b

Always an analogy

Example, "We feel instinctive sympathy for the defendant who pleads, 'I tried to get a job and nobody
would hire me. Only in desperation did I turn to robbery.' Now consider the logically parallel
defense: I tried to seduce a woman legitimately and nobody would sleep with me. Only in
desperation did I turn to rape. 'Nobody would buy that from a rapist, and nobody should buy it from
a robber." --Steven Landsburg, Forbes
Answer: This is an analogical argument by relations.

P1. x is to y as a is to b.
P2. x is R to y.
C. It is probable, therefore, that a is R to b

x = turning to robbery
y = inability to get hired
a = turning to rape
b = inability to seduce a woman legitimately
R = done out of desperation.

P1. ‘Turning to robbery’ is to ‘inability to get hired’ as ‘turning to rape’ is to ‘inability to seduce a
woman legitimately.’

P2. Turning to robbery, due to ‘inability to get hired’ was done out of desperation.
C. It is probable, therefore, that turning to rape, due to inability to seduce a woman legitimately,
was done out of desperation.

Evaluation: In this passage the arguer tries to compare a rapist to a robber. Although people
commit certain crimes out of desperation after legitimate attempts to get what they want, there is a
big difference between the nature of the desperation of the rapist's case and the robber's case. In
the rapist's case, the desperation arises as a result of sexual deprivation. Sex is not a basic need;
that is, one can live without sex. But in the robber's case, the desperation may well arise as a result
of deprivation of food and shelter. These are basic needs; one cannot live without them. The
analogy used here is very bad, and so this argument is logically very weak.

Inductive arguments - Induction by confirmation

If h then o.

o [o1, o2, o3]

It is probable therefore that h

Inductive arguments - Analogical reasoning by properties

X has properties A, B, C

Y has A, B properties

it is probable therefore that Y has property c

Always an analogy