Leibniz, Rowe, and the Problem of Evil: Key Concepts

Logical Consistency and Possible Worlds

The idea that p is consistent with q is a logical premise supposing that there exists a possible world in which both p and q can be true simultaneously. This premise contrasts with the claim that p is contradictory to q, which holds that if p is true, q must be false, and that there can be no possible world in which both are true — nor one in which both are false. When p is consistent with q, the world in which such a premise could hold is one in which a conjunctive proposition may underlie the concepts, or in which the linguistic theory of necessary truth is simply not operative.

Leibniz's Principle of Sufficient Reason and Evil

The Principle of Sufficient Reason (PSR) holds that everything must have a reason or cause, and that nothing can exist or occur without a cause or logical reason supporting its motion or existence. Applied to the universe, this principle presupposes that the world was created by a self-sufficient, infinite being — God — because something cannot come from nothing. Applied to evil, the PSR implies that the existence of evil is likewise sustained by that same infinite being for the purposes of some benevolent end.

The attribute of benevolence is traditionally ascribed to the Christian Triune God, and it is used to rationalize the existence of evil as part of God's plan, as part of the purpose of Redemption, and as a consequence of humanity's exercise of free will.¹ In Leibniz's framework, God — as the supremely rational being — could only have created the best of all possible worlds, meaning that even evil must serve some sufficient rational purpose within the divine order.

Schlesinger's DDS Solution and the Ought-Implies-Can Principle

George Schlesinger's main solution to the problem of evil centers on the concept of the degree of desirability of a state (DDS). According to Schlesinger, the problem of evil dissolves when one recognizes that a being's happiness can be increased without limit. There is no fixed ceiling of well-being that God is obligated to provide, and therefore the presence of suffering does not constitute evidence against a perfectly good God.

The principle that ought implies can holds that if a being ought to behave in a certain way, the means for that being to do so must genuinely exist and be available. Applied to the problem of evil, this means that whatever obstacle appears to prevent a being from attaining happiness is only a surface-level problem: God's grace is sufficient and exceeds the power of evil. When a being desires to cooperate with that grace, evil can be overcome and the desired happiness achieved.

Rowe's Evidential Argument from Evil

William Rowe's evidential argument from evil is an inductive argument grounded in the premise that evil exists and that a good God cannot coexist with — or remain God in — a world where evil is present, because a good God would not permit evil.² Reconstructed in syllogistic form, the argument runs as follows:

Major premise: God is not evil.
Minor premise: Evil exists.
Conclusion: Therefore, God does not exist.

This represents the rational core of Rowe's argument from evil. The conclusion does not follow cleanly from the premises alone, however, because it presupposes an additional claim: that God cannot coexist with evil. This is where Rowe's reasoning becomes circular — his conclusion essentially restates his implicit premise. Rowe's argument is more properly inductive, moving from the observation of apparently gratuitous evil to the probabilistic conclusion that God, as traditionally conceived, likely does not exist.

References

Adams, Marilyn McCord, and Robert Merrihew Adams. The Problem of Evil. Oxford University Press, 1990.

Feinberg, John S. The Many Faces of Evil. Crossway Books, 2004.

Lewis, C. S. The Problem of Pain. Samizdat University Press, 2016.

Wright, N. T. Evil and the Justice of God. InterVarsity Press, 2006.