Shaw and Barry Form of Argument

Shaw and Barry’s Preferred Shaw and Barry’s Preferred Form of ArgumentForm of Argument

Shaw and Barry present severalShaw and Barry present several arguments in a specific form…arguments in a specific form… (e.g. see page #23 in the(e.g. see page #23 in the textbook, arguments 4 – 7).textbook, arguments 4 – 7). We will construct moral We will construct moral arguments in that specific form in arguments in that specific form in order to justify moral judgments.order to justify moral judgments.


Shaw and Barry point out that theShaw and Barry point out that the best way to defend one’s moralbest way to defend one’s moral judgments is to construct a judgments is to construct a soundsound argument in which the moralargument in which the moral judgment is the conclusion of thejudgment is the conclusion of the argument.argument.

Soundness and ValiditySoundness and Validity

A A soundsound argument is a argument is a validvalid deductive argument with all truedeductive argument with all true premises.premises. A A validvalid argument is a deductive argument is a deductive argument in which the truth of theargument in which the truth of the premises guarantees the truth ofpremises guarantees the truth of the conclusion.the conclusion.

Valid ArgumentsValid Arguments

A valid argument does not haveA valid argument does not have to have true premises.to have true premises. A valid argument does not haveA valid argument does not have to have a true conclusion.to have a true conclusion. But, a valid argument with all true But, a valid argument with all true premises must have a truepremises must have a true conclusion.conclusion.


Validity describes a certainValidity describes a certain relationship between therelationship between the premises and the conclusion of premises and the conclusion of an argument.an argument. That relationship is calledThat relationship is called entailment. entailment. The premises entail the The premises entail the conclusion.conclusion.


To say that the premises entailTo say that the premises entail thethe conclusion is simply to sayconclusion is simply to say that that ifif the premises were true, the premises were true, thenthen the conclusion would have the conclusion would have to be true.to be true. That can be the case even if the That can be the case even if the premises are, premises are, inin factfact, false., false.

Valid Arguments - Test Questions:Valid Arguments - Test Questions:True or False? A valid argument must True or False? A valid argument must

have true premises…have true premises…

TRUETRUE? FALSEFALSE?



FALSEFALSEEven though an Even though an

argument is valid, it argument is valid, it might have one or might have one or

more false more false premises.premises.


have a true conclusion…have a true conclusion…

TRUETRUE? FALSE?FALSE?



FALSEFALSEEven though an Even though an

argument is valid, if argument is valid, if it has a false it has a false

premise, it might premise, it might have a false have a false conclusion.conclusion.

Valid Arguments - Test Questions:Valid Arguments - Test Questions:True or False? A valid argument with all True or False? A valid argument with all

true premises must have a true true premises must have a true conclusion…conclusion…

TRUE?TRUE? FALSE?FALSE?

Valid Arguments - Test Questions:Valid Arguments - Test Questions:True or False? A valid argument with all True or False? A valid argument with all

true premises must have a true true premises must have a true conclusion…conclusion…

TRUETRUEA valid argument with A valid argument with

all true premises all true premises MUSTMUST have a true have a true

conclusion.conclusion.

Sound ArgumentsSound Arguments

A A soundsound argument is an argument argument is an argument that is that is validvalid AND has all true AND has all true premises.premises. A valid argument is A valid argument is unsoundunsound if it if it has a false premise.has a false premise. An An invalidinvalid argument is argument is unsoundunsound even if all of its premises are true.even if all of its premises are true.

Sound ArgumentsSound Arguments

A A soundsound argument must have a argument must have a true conclusion because it is validtrue conclusion because it is valid and has all true premises.and has all true premises. Remember: a valid argument with Remember: a valid argument with all true premises must have a trueall true premises must have a true conclusion.conclusion.

Sound Arguments - Test Questions:Sound Arguments - Test Questions:True or False? A sound argument must True or False? A sound argument must





TRUETRUEHaving all true Having all true

premises is one of premises is one of the requirements of the requirements of a sound argument.a sound argument.



TRUETRUEBecause a sound Because a sound

argument is both argument is both valid and has all valid and has all true premises, it true premises, it must have a true must have a true

conclusion.conclusion.


be valid…be valid…



be valid…be valid…

TRUETRUEBeing valid is one Being valid is one

of the of the requirements of a requirements of a sound argument.sound argument.

Sound Arguments - Test Questions:Sound Arguments - Test Questions:True or False? A valid argument must be True or False? A valid argument must be

sound…sound…


Sound Arguments - Test Questions:Sound Arguments - Test Questions:True or False? A valid argument must be True or False? A valid argument must be

sound…sound…

FALSEFALSEIf the valid argument If the valid argument

has a false has a false premise, it is premise, it is

unsound.unsound.

Sound Arguments - Test Questions:Sound Arguments - Test Questions:True or False? A valid argument with all True or False? A valid argument with all

true premises must be sound…true premises must be sound…


Sound Arguments - Test Questions:Sound Arguments - Test Questions:True or False? A valid argument with all True or False? A valid argument with all

true premises must be sound…true premises must be sound…

TRUETRUEThat That is the definition is the definition

of a sound of a sound argument: a sound argument: a sound argument is VALID argument is VALID and has all TRUE and has all TRUE

premises.premises.

Constructing a sound Constructing a sound argument.argument.

Shaw and Barry’s preferred formShaw and Barry’s preferred form of argument is a valid form.of argument is a valid form. Any argument in Shaw and Any argument in Shaw and Barry’s preferred form must be Barry’s preferred form must be valid. valid. But just because an argument isBut just because an argument is in Shaw and Barry’s preferredin Shaw and Barry’s preferred form, it does form, it does notnot have to be have to be soundsound..


Shaw and Barry claim that the bestShaw and Barry claim that the best way to justify a moral judgment isway to justify a moral judgment is to construct a sound argument into construct a sound argument in which the moral judgment is thewhich the moral judgment is the conclusion of the argument.conclusion of the argument. Since a sound argument mustSince a sound argument must have a true conclusion, if thehave a true conclusion, if the argument is sound, the moralargument is sound, the moral judgment must be true. judgment must be true.


When constructing an argument, When constructing an argument, by following Shaw and Barry’sby following Shaw and Barry’s form, the argument will be valid.form, the argument will be valid. To insure that the argument isTo insure that the argument is sound, just be sure that thesound, just be sure that the premises are true.premises are true.


The first premise of an argumentThe first premise of an argument in Shaw and Barry’s preferred in Shaw and Barry’s preferred form is a moral standard (or form is a moral standard (or moral principle).moral principle). The second premise is an The second premise is an alleged fact.alleged fact. The conclusion is a moralThe conclusion is a moral judgment.judgment.


A close inspection of the sampleA close inspection of the sample arguments (p. 23 #4 – 7) revealsarguments (p. 23 #4 – 7) reveals that the form is as followsthat the form is as follows::

PP11: : All All AA’s are ’s are BB’s.’s. PP22: : XX is an is an AA.. ____________________________________________________________________________________________________

∴ XX is a is a BB..


Notice that there are three termsNotice that there are three terms (A, B, and X) and that each term(A, B, and X) and that each term appears twice.appears twice.




By replacing By replacing AA with some with some general type of behavior, andgeneral type of behavior, and BB with some moral language… with some moral language…




……premise 1 becomes a moralpremise 1 becomes a moral standard (or principle), e.g.standard (or principle), e.g. Killing peopleKilling people is is morally wrongmorally wrong..




Now, in premise 2, replace Now, in premise 2, replace XX with some specific issue and with some specific issue and AA with the with the samesame general behavior… general behavior…




… …and premise two becomes anand premise two becomes an alleged fact, e.g. alleged fact, e.g. The ColumbineThe Columbine tragedytragedy involved involved killing peoplekilling people..




… …and the conclusion becomesand the conclusion becomes aa moral judgment, e.g. moral judgment, e.g. TheThe Columbine Columbine tragedytragedy was was morallymorally wrongwrong..




This sample argument:This sample argument:

PP11: : Killing peopleKilling people is is morally wrongmorally wrong.. PP22:: The Colombine trajedyThe Colombine trajedy involvedinvolved

killing peoplekilling people.. ____________________________________________________________________________________________________

∴ The Colombine trajedyThe Colombine trajedy isis morally wrongmorally wrong..

has an non-controversial conclusion.has an non-controversial conclusion.


But it demonstrates the correct form: But it demonstrates the correct form:




Notice the three terms Notice the three terms ((AA, , BB, and , and XX)): :




Each term appears twice, and in just Each term appears twice, and in just the right locations: the right locations:




By following this form, the argument isBy following this form, the argument is sure to be valid. sure to be valid.




To insure a sound argument, just beTo insure a sound argument, just be sure that the premises of the argumentsure that the premises of the argument are true . are true . Since a sound argument must have aSince a sound argument must have a true conclusion…true conclusion… the moral judgment (which is thethe moral judgment (which is the conclusion) must be true!conclusion) must be true!


Those who disagree with the moralThose who disagree with the moral judgment must show that the argumentjudgment must show that the argument is is unsoundunsound.. An unsound argument is either invalidAn unsound argument is either invalid or has a false premise.or has a false premise. Since the argument is in Shaw andSince the argument is in Shaw and Barry’s preferred form, it is valid.Barry’s preferred form, it is valid. Thus those who disagree with theThus those who disagree with the moral judgment must try to show amoral judgment must try to show a premise is false.premise is false.


To defend your argument (and yourTo defend your argument (and your conclusion/moral judgment):conclusion/moral judgment):

you point out that it is a valid argument,you point out that it is a valid argument, and then you must defend your factual and then you must defend your factual claim (premise two),claim (premise two), and you must defend your moraland you must defend your moral principle (premise one).principle (premise one).

Shaw and Barry Form of Argument

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