(For my MCCC Philosophy of Religion students)
1. Explain logical incoherence; or logical contradictoriness.
2. State and explain Mackie's Triad. Give the two underlying assumptions. Define "evil" as gratuitous/pointless suffering.
3. Give Mackie's possible solutions.
If any one of the three statements is false, then there is no logical problem of evil.
Philosopher-atheist J.L. Mackie constructs an argument from evil intended to show the incoherence of theism. One cannot, thinks Mackie, simultaneously affirm the following three propositions (known as "Mackie's Triad"):
1) God is all-powerful.
2) God is all-good.
3) Evil exists.
Just as one cannot simultaneously affirm:
1) John is a bachelor.
2) John's wife's name is Linda.
1) Object X is square.
2) Object X is circular.
With this last example, we see that there is no possible world where an object, X, can be at the same time square and circular. There is, e.g., a possible world where a talking sponge can exist; i.e., it is logically possible that a talking sponge can exist. The term "talking sponge" is not logically impossible (logically incoherent). But "square circle" is.
Mackie's claim is that theism, the idea of an all-powerful, all-good being, is incoherent on the existence of evil. That is, one cannot imagine a possible world where an all-powerful, all-good being coexists with evil.