Final answer:
The argument from evil assumes moral realism and challenges the traditional view of a deity by raising questions about the coexistence of an all-powerful, all-knowing, and all-good deity with moral evil. It leads to discussions regarding human free will, gratuitous evil, and the nature of a supreme being.
Step-by-step explanation:
The argument from evil does indeed presuppose moral realism, which is the belief in the objective reality of moral values. The problem of evil questions the existence of an all-powerful, all-knowing, and all-good deity in the light of the existence of evil, particularly moral evil. Philosophers like David Hume have approached this problem by asserting that if a deity allows for evil and suffering, such a being cannot possess the triple attributes of omniscience, omnipotence, and omnibenevolence simultaneously. This philosophical challenge has led to various theories, including the concept of transworld depravity which suggests that any world created by a supreme deity would inherently contain the possibility of evil due to human free will.
The argument from evil also encounters issues like the existence of gratuitous moral evil, which seems to serve no good purpose and thus challenges the idea that a deity might use evil as a means to bring about a greater good. Ultimately, this complex debate touches upon whether adjustments must be made to our understanding of a supreme being, the nature of evil, or both to reconcile with the observable presence of moral evil.