Alvin Plantinga in his book The Nature of Necessity (1971) has furthered in response to J.L. Mackie’s Evil and Omnipotence (1955) – and among others – a position known as the Free Will Defense. This position, in essence, considers the following proposition:
- (a) God is omnipotent, omniscient, and wholly good, and God creates free men who sometimes preform morally evil actions.
and suggests that (a) is not contradictory or necessarily false. Otherwise explained, the Free Will Defense says that “[a] world containing creatures who are sometimes significantly free [ … ] is more valuable, all else being equal, than a world containing no free creatures at all” . Plantinga’s argument functions in the following way: To show that some given proposition p is consistent with a proposition q is to produce a third proposition r whose conjunction with p is consistent and entails q. Interestingly, proposition r doesn’t need to be true or even known to be true (nor plausible), it just needs to be consistent with p and in conjunction with the latter entail q. The Free Will Defense then seeks to find such a proposition.
However, Quentin Smith (1997)  argues in response to Plantinga by considering the following propositions as implicitly contradictory:
- G. God exists and is omnipotent, omniscient, and wholly good.
- E. There is evil.
Smith concedes that arguments akin to that of Plantinga’s may produce a third proposition r whose conjunction with p entails q; however, his logical argument from evil seeks to provide a third proposition (p) “that is both a necessary truth and whose conjunction with (G) produces an explicit contradiction” . An explicit contradiction, according to Smith, is a “conjunction of propositions one of which is the negation of the other” . Smith believes that this given contradictory proposition – which he considers to be denoted by the symbol (‘p) – can be found within a critique of Plantinga’s assumptions regarding the definition of freedom.
Plantinga in his argument makes a few notable distinctions as to what he means by freedom. For instance, he first says that
[i]f a person S is free with respect to a given action, then he is free to preform that action and free to refrain; no causal laws and antecedent conditions determine either that he will preform the action, or that he will not. It is within his power, at the time in question, to preform the action, and within his power to refrain. 
Thus, we can refer to this understanding of freedom as being significantly free (or external freedom according to Smith), where a person is free with respect to a moral action. However, another notable distinction is with what Smith calls internal freedom: “A person is internally free with respect to an action A if and only if it is false that his past physical and psychological states, in conjunction with causal laws, determine either that he preform A or refrain from preforming A” .
A last distinction would be to identify along with Smith what is known as logical freedom; particularly where “A person is logically free with respect to an action A if and only if there is some possible world in which he preforms A and there is another possible world in which he does not preform A” . Thus, we have the following:
- (1) External Freedom: Person S is able to preform (or refrain from) action A if no external force(s) coerces person S to preform A.
- (2) Internal Freedom: Person S is able to preform (or refrain from) action A if past personal conditions (physical, psychological, etc.) with conjunction to causal laws do not affect their choosing.
- (3) Logical Freedom: Person S is able to preform (or refrain from) action A in possible world W but not-A in some other possible world (say) Y.
Thus, Smith contends that it is possible to be internally as well as externally free but not logically free (i.e., logically determined) with respect to being morally good, as it is in the case of God. Smith writes:
God’s logical determination with respect to moral goodness is entailed by his individual essence, for God’s individual essence is being maximally great, which entails being maximally excellent in every possible world. Maximal excellence [ … ] includes the property of being wholly good. 
Quentin Smith’s Critique
Consider then Plantinga’s statement that we quoted earlier: “A world containing creatures who are sometimes significantly free [ … ] is more valuable, all else being equal, than a world containing no free creatures at all” . Smith interprets Plantinga’s statement here regarding freedom to mean external + internal + logical freedom. However, “does a person who has only external and internal freedom have less metaphysical worth than a person who is free in these two respects and also has logical freedom?” 
In other words, if a person were only to have internal and external freedom, but not logical freedom, does he then have less metaphysical worth than one who happens to have all three kinds of freedom? According to Smith:
The answer implied by Plantinga’s own premises must be no, for God has internal-external freedom but not logical freedom, and God has the greatest possible degree of metaphysical worth. God does not have logical freedom because God has the property of maximal greatness, which includes the property of being wholly good in each world in which he exists.
Thus, the proof of this statement functions in the following way:
- (1) God possesses the maximally valuable consistent conjunction of great-making properties.
- (2) If it were intrinsically better to be logically free with respect to a morally good life than logically determined, and the logical freedom were consistent with God’s omnipotence and omniscience, then God would possess this logical freedom.
- (3) Logical freedom with respect to a morally good life is consistent with omnipotence and omniscience.
- (4) God is logically determined with respect to a morally good life.
- (5) It is false that it is intrinsically better to be logically free with respect to a morally good life than logically determined.
Thus, from this proof we are able to show that some possible world W1 containing N number of persons who always do what is right and who are logically determined with respect to moral goodness would have been created by God instead of some other possible world W2 containing N number of persons who are logically free with respect to a morally good way of life.
Therefore, Plantinga’s assumption where he says that “there are no possible creatures who are internally-externally free with respect to a morally good life but logically determined” is considered false according to Smith.
-  Quoted from God and the Problem of Evil, ed. William L. Rowe (Blackwell Publishing: 2001) p. 93
-  Quentin Smith, Ethical and Religious Thought in Analytic Philosophy of Language (Yale University Press: 1997) see pp. 148-56
-  Quoted from The Impossibility of God, ed. Michael Martin and Ricki Monnier ( Promotheus: 2003) p. 106
-  Ibid.
-  Quoted from Rowe, p. 93
-  Quoted from Martin, p. 107
-  Ibid.
-  Ibid. – emphasis Smith’s
-  See note .
-  Quoted from Martin, p. 109