SYLLOGISTIC REASONING PART 2 Properties and Rules PART 2 Properties and Rules

SYLLOGISTIC REASONING The 4 types of quantifiers The 4 types of causes The proof by the effects The rules of syllogism The 4 types of quantifiers The 4 types of causes The proof by the effects The rules of syllogism

PROPERTIESPROPERTIES PROPERTIESPROPERTIES The 4 types of quantifiers 1. Universal affirmative: ALL S are P 2. Universal negative: NO S is P 3. Particular affirmative: SOME S are P 4. Particular negative: SOME S are NOT P

PROPERTIESPROPERTIES PROPERTIESPROPERTIES The 4 types of causes 1.Material cause: Because S is made of M Why can men breathe? Because everything with lungs can breathe And because all men have lungs Thus, all men can breathe

PROPERTIESPROPERTIES PROPERTIESPROPERTIES The 4 types of causes 2. Efficient cause: Because S is moved by M Why can men breath? Because everything that inhales & exhales can breathe And because all men can inhale & exhale Thus, all men can breathe

PROPERTIESPROPERTIES PROPERTIESPROPERTIES The 4 types of causes 3. Formal cause: Because S is an M Why can men breathe? Because all mammals can breathe And because all men are mammals Thus, all men can breathe

PROPERTIESPROPERTIES PROPERTIESPROPERTIES The 4 types of causes 4. Final cause: Because S is for M Why can men breathe? Because all that must live on earth can breathe And because all men are for life on earth Thus, all men can breathe

PROPERTIESPROPERTIES PROPERTIESPROPERTIES The 4 types of causes Some Practice The 4 types of causes Some Practice Why can humans be religious? Because all spiritual souls can be religious material 1. Proof by the material cause: Because all that God attracts can be religious efficient 2. Proof by the efficient cause: Because all that is in God’s image can be religious formal 3. Proof by the formal cause: Because all that is for God can be religious final 4. Proof by the final cause:

PROPERTIESPROPERTIES PROPERTIESPROPERTIES The proof by the effects Because the effect of S is M Why can men breathe? Because what rejects water & CO2 can breathe And because all men rejects water & CO2 Thus, all men can breathe

RULESRULES RULESRULES  2 premises Major: M is P – Minor: S is M # 1: The BARBARA formula  1 conclusion S is P  3 terms twice S twice subject (minor & conclusion)  … in good order M is P ► S is M ► S is P M once subject of the major and once predicate of the minor P twice predicate (major & conclusion)

RULESRULES RULESRULES negative  No valid conclusion with 2 negative premises # 2: The quantifiers Because no human is an angel And because no seraphim is human Thus, no seraphim is an angel

RULESRULES RULESRULES  No valid conclusion with 2 negative premises # 2: The quantifiers Because some Americans are saints And because some humans are American Thus, some humans are saints  No valid conclusion with 2 particular premises

RULESRULES RULESRULES  No valid conclusion with 2 negative premises # 2: The quantifiers Because no human is from the moon And because all saints are human Thus, no saints are from the moon  No valid conclusion with 2 particular premises  1 negative premise = a negative conclusion

RULESRULES RULESRULES  No valid conclusion with 2 negative premises # 2: The quantifiers Because some rational creatures are happy And because all humans are rational creatures Thus, some humans are happy  No valid conclusion with 2 particular premises  1 negative premise = a negative conclusion  1 particular premise = a particular conclusion

RULESRULES RULESRULES  A valid syllogism can be false if a premise is false # 3: Validity & Truth Because all saints are humans And because all angels are saints Thus, all angels are humans VALID

RULESRULES RULESRULES  A valid syllogism can be false if a premise is false # 3: Validity & Truth Because all saints are humans And because some saints are Christians Thus, all Christians are humans TRUE  A true conclusion can follow an invalid syllogism