Theists frequently argue that nontheists must affirm the following: (1) If there is no God, each person must define "good" and "evil" for herself. (2) If each person must define "good" and "evil" for herself, there can be no objective moral standard. (3) God does not exist. (4) Therefore there can be no objective moral standard (i.e., all moral principles are relative). Some nontheists agree (e.g., Sartre) and attempt to live with the implications of (4). Others deny (2), claiming that the existence of an objective moral standard is not dependent on religious commitment. Kai Nielsen is one of the best known and most outspoken members of this group. Nielsen argued that "the nonexistence of God does not preclude the possibility of there being an objective standard on which to base [moral] judgments." He has recently reaffirmed this claim:

The argument from conscience is one of the only two arguments for the existence of God alluded to in Scripture, the other being the argument from design (both in Romans). Both arguments are essentially simple natural intuitions. Only when complex, artificial objections are made do these arguments begin to take on a complex appearance. The simple, intuitive point of the argument from conscience is that everyone in the world knows, deep down, that he is absolutely obligated to be and do good, and this absolute obligation could come only from God. Thus everyone knows God, however obscurely, by this moral intuition, which we usually call conscience. Conscience is the voice of God in the soul.