Equivocality isn't a common word, but it's used a lot in theological circles. Equivocality refers to words that have ambiguous and/or multiple meanings. The two go hand in hand. If a word can mean many different things, and you use that word, I can be unsure about what, exactly, you mean.
A familiar example of equivocality was observed decades ago when kids started using the word "bad" to mean something good. The equivocality of "bad" made sentences like "This is bad." ambiguous. Was the thing bad or good?
One of Hart's arguments in That All Shall Be Saved concerns how the doctrine of eternal conscious torment have made words like "good," "loving," "just," and "merciful" equivocal, and therefore meaningless.
For example, many of those who espouse (or hope for) universal reconciliation will often point to the doctrine of eternal conscious torment and ask, "How could torturing a person for all eternity be just?" The punishment must fit the crime, right? Consequences must be proportionate to the offense. That's what we mean by "justice," that it finds this proper balance. The famous principle of lex talionis--"an eye for an eye"--illustrates this: retaliation must be proportionate to the damage you've incurred, and no more. Justice is balanced and proportionate. That's what the word means.
So how, it is pointed out, can a infinitely painful punishment of an infinite duration ever be just, ever be balanced and proportionate to our offense?
The answer, at this point, from the defender of eternal conscious torment, is to dismiss human definitions of justice. "God's justice is different from our justice," we are told. "And we cannot apply our definitions of justice to God," we are informed.
To be sure, there is a truth here. We have to be very careful in how we use our words in relation to God. (Thank you, Thomas Aquinas.) But we can't completely evacuate the meaning of words like "justice" and "love" of all content. To do so makes our speech about God equivocal and therefore meaningless. Specifically, in the case of eternal conscious torment, if something we take to be manifestly evil is described as loving, just, and good, then those words are rendered meaningless.
And the situation is even worse than that. When words like "justice" and "goodness" can mean "unjust" and "evil" we've opened Pandora's Box. When words lose their meaning we can easily justify our wickedness toward others because God Himself is "good" in just this wicked way.
In summary, I think one of the deep insights of Hart's That All Shall Be Saved is how much damage the doctrine of eternal conscious torment does to our language about God. If our faith allows us to call evil things good, we're in trouble.
We are speaking with hell damaged words.
