Moral Reasoning What is

moral reasoning?Moral reasoning is ordinary critical reasoning or critical thinking applied to moral arguments.

Critical ThinkingThe careful, systematic evaluation of statements and arguments.

Critical Thinking

Reasoning Well Involves Arguments

Argument does not mean a verbal dispute.

Arguments

An Argument Is One or More Statements, Called Premises, Attempting to Prove Another Statement, Called a Conclusion

Statements and Arguments

The statement that is being supported by the others is the conclusion.

The supporting statements are called premises.

Arguments

Logic: The study of the formal principles of reasoning

Arguments

Deductive Argument: the truth of the premises guarantees the truth of the conclusion

Deductive Arguments Example (Valid): 1. If it snows,

then it is cold (premise)

2. It snows (premise)

3. Therefore, it is cold (conclusion)

VALID DEDUCTIVE ARGUMENT: The argument is in the proper form

Deductive Arguments Example (Invalid): 1. If it snows, then it

is cold (premise) 2. It is cold

(premise) 3. Therefore, it

snows (conclusion)

Deductive Arguments INVALID : The

argument is not in the proper form.

Informal  testing for deductive validity:

Can You Think of a counter example?

If yes, the argument is invalid.

Deductive Arguments Example: 1. If it snows, then

it is cold (premise) 2. It is not cold

(premise) 3. Therefore, it

does not snow (conclusion)

Deductive Arguments Example: 1. If it snows, then it

is cold (premise) 2. It does not snow

(premise) 3. Therefore, it is not

cold (conclusion)

Deductive Arguments If Tom Cruise is a

bulldog then he has four legs (Premise)

Tom Cruise is a bulldog (Premise)

Therefore, Tom Cruise has four legs (Conclusion)

Is the Argument Valid?

Have we proven that Tom Cruise has four legs?

Deductive Arguments If it is determined that the argument

is valid it must next be determined if the argument is sound.

A sound argument is a valid argument with true premises.

Deductive Arguments If Tom Cruise is a

bulldog then he has four legs

Tom Cruise is a bulldog

Therefore Tom Cruise has four legs

Is the Argument Sound?

Arguments

Inductive Argument: the truth of the premises makes the truth of the conclusion more probable

Inductive Arguments Examples:

1.All observed emeralds have been found to be green 2.Therefore, the next observed emerald will be green.

1.In the past, sugar cubes have dissolved in water 2.Thus, this sugar cube will dissolve in water.

1.70% of BCCC students in the sample are from Bristol

2. Hence, 70% of BCCC students are from Bristol

Inductive ArgumentsStrong Inductive Argument: Gives probable support to its conclusion such that, if its premise is true, its conclusion is also likely to be true.

Ninety percent of Students at BCCC have perfect SAT scores. Therefore, John (a student at BCCC) probably has a perfect SAT score.

Inductive ArgumentsWeak Inductive Argument: : Does not give probable support to its conclusion, and even if its premise is true, its conclusion is not more likely to be true

One percent of Students BCCC have perfect SAT scores. Therefore, John (a student at BCCC) probably has a perfect SAT score.

Inductive Arguments If it is determined that an inductive the

argument is strong it must next be determined if the argument is cogent.

A cogent inductive argument is a strong argument with true premises.

Inductive ArgumentsNinety percent of Students at BCCC have perfect SAT scores. Therefore, John (a student at BCCC) probably has a perfect SAT score.

Is the Argument Strong?Is the Argument Cogent?

Unstated Premises Many times

arguments have one or more unstated premises that need to be added to support the conclusion.

Sally’s dog is a bloodhound therefore it has a keen sense of smell

Unstated Premises It is February, so I

will dress warmly Drugs should not be

legalized

Analyzing ArgumentsReconstruct the Argument

1. Find the conclusion.

2. Find the premises

3. Find any unstated premises

“The glove doesn’t fit so you must acquit”

Conclusion:

* Defendant should be acquitted Premise(s):

* The glove doesn't fit the defendant (premise - stated)

Unstated premises:

* If evidence does not fit the defendant, then the defendant should be acquitted (premise - unstated)

* The glove is evidence (premise - unstated)

Analyzing Arguments Evaluate the argument

1. Is the argument valid? (Can I think of a counter example?)

2. Are the premises true?

Evaluating the Argument

1. Is the argument valid?

(Can I think of a counter example?)

2. Are the premises true?

– If evidence does not fit the defendant, then the defendant should be acquitted

– The glove is evidence

– The glove doesn't fit the defendant

– Therefore, defendant should be acquitted

Logical Fallacies Mistakes in logic when presenting our

arguments.

Formal Fallacy: An invalid argument

Informal Fallacy: Type of bad reasoning that can only be detected by examining the content of the argument.

Informal Fallacies Begging the

Question

Assuming what you are trying to prove

“Capital punishment is wrong because it is immoral”

Informal Fallacies Ad Hominem Attack

Attack on your opponent rather that his or her argument

“The only reason that you think Capital punishment is wrong is because you are a bleeding heart liberal”

Informal FallaciesStraw Man:

Misrepresenting someone’s claim or argument so it can be more easily refuted

Actual statement: • “We should liberalize the

laws on selling alcohol in PA.”

Straw-man characterization: • “No. Any society with

unrestricted access to intoxicants loses its work ethic and goes only for immediate gratification.”

Informal Fallacies Red Herring:

Sidetracking the argument with an irrelevant issue

“Honda makes the best cars” --- “No they don’t their workers are treated poorly”

Informal Fallacies Hasty Generalization:

Drawing general conclusions from a small sample

“A number of professional athletes have been convicted of crimes therefore all professional athletes are criminals”

Moral Arguments Every moral

argument should offer at least one premise that is a moral statement.

A moral statement is a statement affirming that:

An action is right or wrongA person is good or badA person’s motive or character is good or bad

•“Capital punishment is wrong”•“Harry should not lie”

Moral Arguments Every moral

argument should offer at least one premise that is a non-moral statement.

A non-moral statement is a statement affirming that something is true or false, without assigning a moral value to it.

•“Many people think that Capital punishment is wrong”•“Harry did not lie”

Avoiding Bad Arguments

Bad arguments all share one of the following two problems:

A conclusion that doesn’t follow from its premises.

At least one false premise.

Arguments Barack Obama is a

good president Barack Obama is a

bad president