Modern Philosophy
 
Deductive Validity of Spinoza's Basic Argument

(an expansion on summary of Garrett Thomson, p. 53)
 

A Study Guide for Students in Bill Gay's Modern Philosophy Class

  A. First Argument   1. Premises and conclusion "Substance is independent"

"Anything that has an external cause cannot be independent"

"Therefore, substance does not have an external cause"
2. Reformulation as EAE-2 Categorical Syllogism No things with External causes are Independent All entities that are Substance are Independent Therefore, No entities that are Substance are things with External causes
 
B. Second Argument

1. Premises and conclusion

"Substance does not have an external cause" [conclusion of 1st argument] "Everything must have a cause" "Therefore, substance is its own cause" 2. Reformulation as AEE-2 Categorical Syllogism All Things are entities with a Cause No entities that are Substance are things with an External cause Therefore, No entities that are Substance are things with an External cause
  Obversion of Conclusion: All entities that are Substance are non-(things with an External cause)
  Equivalence of Predicate of Obversion: All entities that are Substance are Own cause
C. Third Argument

1. Premises and Conclusion

"Substance is its own cause" [conclusion of 2nd argument] "No finite thing is its own cause" "Therefore, substance is infinite" 2. Reformulation as EAE-2 Categorical Syllogism No Finite things are Own cause All entities that are Substance are Own cause Therefore, No entities that are Substance are Finite things Obversion of Conclusion: All entities that are Substance are non-(Finite things)
  Equivalence of Predicate of Obversion:

All entities that are Substance are Infinite