My thoughts here are largely in response to this post, though I hope that they have value on their own as well.
It has been suggested that the classical doctrine of impassibility is an assertion of the emotionlessness of God. I reject this, both as a depiction of the history of dogma and as a theological assertion. While it may be said that the post-scholastic, Western conception of impassibility necessitates a God without emotion, the historical doctrine of impassibility, even the basis of that Western doctrine, is not directly related to the ability of God to feel.
The doctrine of God’s impassibility (formulated, as was almost all early doctrine, in Greek) regarded His apatheia (impassibility or dispassion), that is His lack of pathos (passion). As with most theological discussion, the language here took on a specialized meaning so that passion cannot simply be equated with emotion (which was never the meaning of “pathos” to begin with). Therefore, to truly understood what is meant in an authentically classical definition of impassibility, one must first determine the classical defition of that which impassibilty says God is without: pathos.
Kallistos Ware, in his introduction to John of Sinai’s Ladder of Divine Ascent, writes that passions are “regarded as the contranatural expression of fallen sinfulness.” Pathos represents the human perversion their emotions, their natural impulses. Pathos are the sinful impulses of a fallen creation. If a direct relationship to emotion is necessary, then passion can be said to be our subjugation to our corrupted emotions rather than our domination and purification of them. Anger, for example, is pathos not because it is an emotion but because it has been perverted to ungodly ends. Desire is a pathos not because it is an emotion but because it has been coopted by humanity for the purpose of indulgence. Pathos is by its very definition sin.
Impassibility then becomes an ethical imperative, rooted in the nature of God, which is intended for humans. God governs His pure emotion rather than being governed by them, so humanity must transfigure and govern their emotions. The impassibility of God is a goal for man to achieve; in Ware’s words “…it is a reaffirmation of the pure and natural impulses of our soul and body. It connotes not repression but reorientation, not inhibition but freedom; having overcome the passions, we are free to be our true selves, free to love others, free to love God. Dispassion, then, is no mere mortification of the passions but their replacement by a new and better energy.”
Clearly passion refers to something other than the emotive aspect of the human soul, as the fathers vigorously affirm the God given virtue of emotionality:
“Hatred against the demons contributes greatly to our salvation and helps our growth in holiness.” Evagrius Ponticus, “On Discrimination,” 9.
Evagrius also writes that one should experience, while fasting, the emotions of joy “at the blessings that await the righteous” and fear of resurrection and “that fearful and awesome judgment-seat,” because “in this way you will have the means for helping others and for mortifying the passions of your body” (“On Asceticism and Stillness”)
“We should be afraid of God in the way we fear wild beasts. I have seen men go out to plunder, having no fear of God but being brought up short somewhere at the sound of dogs, an effect that fear of God could not achieve in them.” John Climacus, “Ladder of Divine Ascent”
The dichotomy between emotion and passion is evident in Diadochos’ contrast of real joy (an emotion) and counterfeit joy (a diabolical passion): “When we experience things in this manner, we can be sure that it is the energy of the Holy Spirit within us. For when the soul is completely permeated with that ineffable sweetness, at that moment it can think of nothing else, since it rejoices with uninterrupted joy. But if at that moment the intellect conceives any doubt or unclean thought, and if this continues in spite of the fact that the intellect calls on the holy name…then it should realize that the sweetness it experiences is an illusion of grace, coming from the deceiver with a counterfeit joy. Through this joy, amorphous and disordered, the devil tries to lead the soul into an adulterous union with himself.”
Passion then is not simply equated to emotion but is the corruption of and domination by emotion. This, at least, is the testimony of the Church Fathers.
(This, I might add, is a view of passion and impassibility consistent with the Bible, if not the exclusive biblical view. While apatheia is never used in the New Testament, the three instances of pathos and its forms are all negative leading one to conclude that the absence of passion is a virtue. The three occurrences of pathos, moreover, never tie pathos to emotion strictly but always in some sense to control by passion as opposed to self-control: 1 Thess 4:3-5: “It is God’s will that you should be sanctified: that you should avoid sexual immorality; that each of you should learn to control his own body in a way that is holy and honorable, not in passionate lust like the heathen, who do not know God;” Rom 1:26: “For this reason God gave them over to degrading passions;” Col 3:5: “Therefore consider the members of your earthly body as dead to immorality, impurity, passion, evil lust, and greed, which amounts to idolatry.” Notably God is never described as being “passible” since pathos is a sinful state.)
Therefore, in its original formulation, impassibility is not a feature of the divine distinct from humanity. Instead, it is the shared possession of God and His creature in its natural state. Impassibility is a mandate for humanity in an attempt to once again recapture our created purity, our image of God. “Blessed dispassion raises the poor mind from earth to heaven, raises the beggar from the dunghill of passion.” (John Climacus) It requires that people not be subject to their pathos (sinful impulses) but that purified emotion should be subject to them in order that they may be subject to a dispassionate God. Quotes from a few fathers should suffice to demonstrate that this is the case.
“When the intellect rescues the soul’s senses from the desires of the flesh and imbues them with dispassion [apatheia], the passions shamelessly attack the soul, trying to hold its senses fast in sin; but if the intellect then continually calls upon God in secret, He, seeing all this, will send His help and destroy all the passions at once.” Isaiah the Solitary, “On Guarding the Intellect,” 14.
John of Carpathia parallels sin and passion: “Once certain brethren, who were always ill and could not practice fasting, said to me: ‘How is it possible for us without fasting to rid ourselves of the devil and the passions?’ To such people we would say: you can destroy and banish what is evil, and the demons that suggest this evil to you, not only by abstaining from food, but by calling with all your heart on God.” (“Texts for the Monks of India,” 68)
More telling still is the exposition of impassibility/dispassion (both apatheia) by Ilias the Presbyter in his “Gnomic Anthology,” I.71-74, where he intimately connects passion to sin and impassibility to sinlessness: “Pasionateness is the evil matter of the body…the self-indulgent man is close to the impassioned man; and the man of impassioned craving to the self-indulgent man. Far from all three is the dispassionate man. The impassioned man is strongly prone to sin in thought, even though for a time he does not sin outwardly…the man of impassioned craving is given over freely or, rather, servilely, to the various modes of sinning. The dispassionate man is not dominated by any of these degrees of passion…Dispassion is established through remembrance of God.”
Gregory Palamas notes that the goal of ascetic practice is the attainment of impassibility, that is to no longer be “dominated by passionate emotions:” “In every case, those who practice true mental prayer must liberate themselves from the passions, and reject any contact with objects which obstruct it, for in this way they are able to acquire undisrupted and pure prayer…for the body’s capacity to sin must be mortified” (“The Hesychast Method of Prayer,” II.ii.6).
In addition to an ethical goal for humanity restored to its pure created state, there is another function of the impassibility of God in the Fathers. The insistence on impassibility is a tacit affirmation of the incomprehensibility of God, part of a theology of negation which says that God is no confined to our categories of emotionality. Therefore, the kataphatic assertion that God loves/hates/rejoices/burns with anger is both accepted and countered with the apophatic assertion that God is impassible, and this in turn should be accepted and then met with the even more apophatic assertion that God is beyond impassibility. Nikitas Stithatos expresses the paradox in “On Spiritual Knoweldge, Love, and the Perfection of Living,” 1: “God is dispassionate Intellect, beyond every intellect and beyond every form of dispassion.” [And as a way of cheating to further prove my previous point about the ethical implications of this, he immediately continues:] “If on account of your purity these qualities have been bestowed on you and are richly present in you, then that within you which accords with the image of God has been safely preserved and you are now a son of God guided by the Holy Spirit; for all who are guided by the Spirit of God are sons of God.”
Thus, when Anselm formulates what becomes the “classical” doctrine of impassibility for the West, he is not truly reiterating what has always been held by the church universal. Instead, he is expressing and justifying what he believes has been taught in proto-scholastic terms that will take hold in the West. His sentiment is rooted neither in the sinlessness nor the incomprehensibility of God expressed by the fathers who preceded him:
But how are You at once both merciful and impassible? For if You are impassible You do not have any compassion*; and if You have no compassion Your heart is not sorrowful from compassion with the sorrowful, which is what being merciful is. But if you are not merciful whence comes so much consolation for the sorrowful?
How then are you merciful and not merciful, O Lord, unless it be that You are merciful in relation to us and not in relation to Yourself? In fact, You are [merciful] according to our way of looking at things and not according to Your way. For when You look upon us in our misery it is we who feel the effect of Your mercy, but You do not experience the feeling. Therefore You are both merciful because you save the sorrowful and pardon sinners against You; and You are not merciful because You do not experience any feeling of compassion for misery. (Proslogion, 8)
In fact, just the opposite, this view of God’s impassibility is motivated by our ability categorize God, the opposite intention of the original proponents of impassibility. Rejecting these scholastic trends that were creeping into Eastern theology, Gregory Palamas writes:
By examining the nature of sensible things, these people have arrived at a certain concept of God, but not at a conception truly worthy of Him and appropriate to His blessed nature…wrapped up in this mindless and foolish wisdom and unenlightened education, they have calumniated both God and nature. (Triads, I.1.18)
A good formal theology will always be fundamentally apophatic, and thus affirms that God transcends all human categorization including form and emotion, but the motivation is something quite different than a scholastic understanding of impassibility. The beautiful paradox of God is that we can at one time affirm that He transcends all emotional categorization and at the same time truly declare that we experience His love: not feigned love or effects which are analogous to the effects of love but love that is true and pure, the perfect expression of how He created His creatures to experience love. When true impassibility is applied to God it is first and foremost a defense of God’s sinlessness, since pathos is a patristic term which refers to our contranatural impulses (which all ought to agree are absent in God). From there, impassibilty may be employed as an apophatic category which rejects the finitude of God, even from being restricted truly into the category of impassibility. What impassibility can never be is an assertion that we have an unfeeling God, indifferent to the plight of His creation and incapable of interacting with it in any genuinely personal way. Neither Scripture nor the Fathers who formulated the doctrine of impassibility necessitate this, and all good sense seems to prevail against it. Most importantly, the testimony of the Incarnation positively precludes it, or else the sorrow of Jesus in the garden and the anger in the temple are instances of the divine succombing to the human rather than the human conforming to the divine, something which is particularly untenable.
See also: Appendix to the Apology
*As almost a curiosity, it is worth noting that Anselm’s problem here is undoubtedly partly linguistic. In Latin compassion and passion clearly have the same root, the Latin pati for “to suffer.” A Greek would never have seen dispassion as opposed to compassion, since in Greek pathos forms no part of the etymology of either mercy (eleos) or compassion (oiktirmos).