Module 2: Moral Reasoning

Chapter 2: Moral Reasoning

Moral Reasoning

A set of reasons and a conclusion that these reasons are meant to support

Argument

A set of reasons and a conclusion

Logical Validity

The feature of an argument that guarantees the truth of its conclusion, on the assumption that its premises are true

Sound Arguments

a valid argument with true premises

3 part test to separate a valid argument from an invalid one

1. Identify all of an arguments premises

2. Imagine all of them are true

3. Then ask yourself: supporting that all of the premises are true, could they conclusion be false?

Sound arguments contain only

true premises

Arguments are valid or invalid, sound or unsound, NOT

true or false

Sufficient Condition

to guarantee (being human is a sufficient condition of being mammal)

Necessary Condition

requirements (having $ is a necessary condition of being a millionaire)

Biconditional

a claim that supplies a condition that is both necessary and sufficient for something

Modus Ponens

1. P → Q

2. P

3. ∴ Q

Modus Tollens

1. P → Q

2. ⊥ Q

3. ∴ ⊥ P

Hypothetical Syllogism

1. P → Q

2. Q → R

3. ∴ P → R

Fallacy

a mistake in reasoning

formal fallacy

a kind of argument all of whose instances are logically invalid

fallacy of denying the antecedent

1. P → Q

2. ⊥ P

3. ∴ ⊥ Q

fallacy of confirming the consequent

1. P → Q

2. Q is True

3. P is True

Ad Hominem Fallacy

Occurs when you try to undermine a position by attacking the person who is advancing it.

Appeal to irrelevant emotions

Someone tries to convince you of a claim by playing on your emotions.

Appeal to authority

Relying on authority figures to substantiate a position outside their area of expertise.

Straw Man Fallacy

Depicts an opponents position in a way that makes it easy to refute, thereby diverting attentions from the real position being advanced.

Appeal to Ignorance

1. When one thinks a claim is true because it hasn't been proven false

2. When one thinks a claim is false because it hasn't been proven true

Hasty Generalizations

Occurs when someone illicitly draws a general lesson from only a small handful of cases