Defending the premises

The key to a successful argument

Writing a good argumentative essay

• To present a series of valid deductive arguments

• to offer evidence that the premises of your argument are true

• to defend your argument from cogent objections

• to put this all into readable prose

Reason and Evidence

I. Reason•Proper Argument Form•E.g. modus ponensIF A then BATherefore, B

II. Evidence•Proof that the premises of your argument are true or that it is reasonable to accept them•Requires research and creative thinking•II is a lot more work than I

• P1: All Killing of an Innocent Person is Wrong• P2: The Fetus is an Innocent Person• C: Killing of fetuses is Wrong

All A are B

• All Killing of Innocent People is Wrong• Defense: ?

All A are B

• P1: All Killing of Innocent People are Wrong• DEFENSE OF P1: The prohibition against killing

is perhaps the oldest moral code in existence, adopted by ever civilized nation and respected and honored in all places. Christian, Buddhist and Islamic traditions all outlaw murder.

• EVIDENCE• Quotes from Christianity, Buddhism, Islamic

sources• ARGUMENT TYPE: Argument from Example• At least three sources

X is a B

• P2: The fetus is an (innocent ) Person• Defense:

X is a B

• P2: The fetus is an innocent person• Defense: A person can be defined as whatever

has the genetic code of the human species• Evidence: Three sources to provide the

definition of what is a person• Argument Type: Argument from Example

Outline

• Premise 1:

• Defense:

• Evidence:

• Argument Type:

Hint: It is often better to change “IF…then” statements to “ALL”

Modus Ponens• P1: If the fetus is a person it

is wrong to kill it• P2: the fetus is a person• C: it is wrong to kill the

fetus

Categorical• P1: All killing of people is

wrong• P2: The fetus is a person• C: The fetus is wrong

Modus Ponens• P1: If there is not an

expectation that cloning would be successful, then we should not engage in cloning

• P2: There is not an expectation that cloning would be successful

• C: We should not engage in cloning

Categorical• P1: Only potentially

successful medical practices should be engaged

• P2: There is not an expectation that cloning would be successful

• C: We should not engage in cloning

The Two parts of your argument

• THEORETICAL• “It is always wrong to

kill an innocent human being”

• Defense requires that you must offer a theory of what makes something right and wrong

• FACTUAL• “The fetus is an

innocent human being”• Defense requires you

specify the factual/scientific criteria for what makes something human

• P1: Only potentially successful medical practices should be engaged

• P2: There is not an expectation that cloning would be successful

• C: We should not engage in cloning

Theoretical/General• P1: Only potentially

successful medical practices should be engaged

• This is a theoretical claim about what sort of medical practices a society would engage in

Factual/Specific• P2: There is not an

expectation that cloning would be successful

• This is a factual claim about how whether specific instances of cloning have been successful

Exercise 1

• Look at your argument and identify • Theoretical Claim• Factual Claim

Student Example

• P1: All things that cause unnecessary suffering are unjustifiable

• P2:Animal experimentation causes unnecessary suffering

• C: All animal experimentation is unjustifiable

Theoretical/General• All things that cause

unnecessary suffering are unjustifiable

Factual/Specific• Animal experimentation

causes unnecessary suffering

Theoretical/General• All things that cause

unnecessary suffering are unjustifiable

• Defense:• Evidence:• Argument type

(examples/authority/causal)

Factual/Specific• Animal experimentation

causes unnecessary suffering

• Defense• Evidence:• Argument type• (examples/authority/causal)

Theoretical

P1: All things that cause unnecessary suffering are unjustifiableDefense: John Stuart Mill’s philosophy of Utilitarianism, which argues that the good is what brings about the greatest happiness for the greatest numberEvidence: Text from Mill’s bookArgument type: Argument from authority

Factual/Specific

P2: Animal experimentation causes unnecessary sufferingDefense: Look at a number of specific examples of animal experiments to demonstrate they cause unnecessary sufferingEvidence: Newspaper articles, academic journals where such experiments are reportedArgument type: Argument from examples

Exercise 2

• Review your premises with your partner and discuss

• 1. How you would defend your premises?• 2. What evidence would you use?• 3. What argument type?

Next Step:

• For each of your premises, sketch out a defense of each of your premises, suggest what evidence you would provide and what type of argument you will use

• Premise 1

• Defense

• Evidence

• Argument Type:

• Premise 2

• Defense

• Evidence

• Argument Type: