Solomon's commandment, literally understood, was a demand that the baby be cut in half. But it would be absurd and myopic to think that this is actually what he wanted. Rather, he gives a commandment that he doesn't intend be obeyed in order to discern which woman is the true mother. He is trying to do something else with his words than is typically understood of imperative statements; he has no intention at all that it be obeyed.
God also engages in this kind of activity, I think. He tells Moses after the Israelites worshiped the golden calf: Now let me alone, so that my wrath may burn hot against them and I may consume them, and I will make of you a great nation (Exod 32.10). Of course, Moses intercedes for them, and then the LORD changed his mind about the disaster that he planned to bring on his people (32.11-4). It is not as if God did not know that Moses would intercede. Rather, he provokes Moses' intercession precisely by telling him to leave him alone, and through the threat that he will destroy the Israelites.
Consider also what he tells Ezekiel:
Again, though I say to the wicked, "You shall surely die," yet if they turn from their sin and do what is lawful and right ... they shall surely live, they shall not die. None of the sins that they have committed shall be remembered against them (Ezek 33.14-6).
In this case, even a certain threat of death can be set aside if the sinner repents, and nothing they have done will be remembered against them! God's threats, uttered in the most certain and unambiguous language, are never final. Why is this? Because I have no pleasure in the death of the wicked, but that the wicked turn from heir ways and live (33.11).
Now I have been wondering whether or not the universalist might make use of these texts in his understanding of the final judgment and hell. Suppose we grant for the moment that the proper interpretation of the various relevant hell texts (e.g., Mt 25.46) implies that the punishment of the damned will go on forever, without end. (I happen to question this, but I will grant it for the moment.)
We have already seen that a threat of death and judgment, even formulated in unambiguous terms, is not necessarily going to be realized, if the sinner repents. Moreover, God can make use of a threat for other purposes than telling the threatened person what will happen; he may make a threat while having no intention whatsoever that it be realized. Language can be used in many other ways. Why, then, might God make threats about eternal hell, if they are not to be realized?
God simultaneously tells Christians to pray for all persons, precisely because God desires everyone to be saved and to come to the knowledge of the truth (1 Tim 2.1-4). Christ gave himself up as a ransom for all persons (vv. 5-6), showing that his desire is the salvation of all, and he is willing to give his life for this. Moreover, the sort of character birthed in a Christian who has the Spirit of God within her is such that the damnation of a sinner is unthinkable, repulsive: the fruit of the Spirit is love, joy, peace, patience, kindness, generosity, faithfulness, gentleness, and self-control (Gal 5.22-3). Such a person as this doesn't want the destruction of a sinner but her restoration, and this is because God himself gives her such sentiments!
So there is an apparent tension: God wants the salvation of all persons, and makes Christians to desire the same, and moves them even to pray for the salvation of all persons, while simultaneously threatening in (tentatively admitted) uncertain terms that the unrepentant will be punished forever with no hope. How can a universalism be maintained?
Such an "ethical" universalism works like this. God makes use of the threats of hell in order to motivate repentance on the part of sinners, on the one hand, while also motivating sympathy and pity in Christians, on the other. He moves Christians to pray for the salvation of the world because this is what he desires, and if they are to be transformed into his image, they must desire the same. God has no intention of refusing the prayer of his saints (which is the prayer he himself inspires, as Catherine of Siena herself realized). Still, he requires that we preach that hell is eternal, and that sinners will suffer forever, because of the motivational power that this threat has.
In a way, we might understand the role of the Christian as akin to Jonah's. God knew that the Ninevites would repent. Still, the message that Jonah preached was unambiguous and hopeless: Forty days more, and Nineveh shall be overthrown! (Jon 3.4). The point is to teach and inspire love and compassion and selfless prayer on the part of the prophet -- or in the present case, on the part of Christians.
So what we have is a universalism that permits the various hell texts be interpreted along traditionalist lines. This is an ethical universalism because the universalist conclusion is associated with Christian ethics, rather than a dogmatic reading of the various hell texts. (I am not dead-set on this particular name for this reading.) This is a universalism that doesn't "say" that the torments will end, and thus doesn't seem to come under the condemnation of the Fifth Ecumenical Council, and yet prays for the salvation of the whole world and all sinners and knows and expects this intercession to be obeyed, because God himself demands it.