My feeling is that this is a conflict in terms.
Happiness has to occur in time and the Eternal places us outside of time. So Eternal Happiness on its surface does not make sense, per se.
However, if one hypothesizes a soul, or something which is eternal within us, then we can get the idea of there being some part of us that could be in eternal happiness in heaven or eternal torture in hell. This is what Dante shows us in his Comedy. The problem with this idea is that it means one must postulate a transcendental that takes us beyond our place in the world in space and time. The difficulty is that it leads to nihilism. For instance, if you think that there is the possibility of eternal happiness in heaven or eternal suffering in hell that it has a tremendous effect on life, wich destroys the roots of happiness in life itself. In general, what happens is that we worry about going to hell, and we tend to not assume that we are going to heaven, and this transcendental worry or anxiety itself tends to distract one from life itself and undermines achieving happiness in ones life at any given moment. This undermining of happiness in life is a real problem, and so the idea of “Eternal Happiness” actually saps our existential happiness in life and that is its nihilistic effect, distracting us from our life as lived by a possibility that we hypothesize, but do not know if we will realize, because we do not actually know that these transcendentals exist — no matter what we believe. And this is the problem with religion in general — that it hypothesizes transcendentals which are believed but not known, and this tends to lead to suffering now, and perhaps missing the life that we are leading now, in the name of some out-of-time future state that may not occur, but whether it occurs or not is irrelevant to what is going on in our lives now. This is why Nietzsche thought that most religions are life denying and thus destructive to life itself.
Nietzsche thought life (our embodied immanence) was the most important thing and that we should affirm it rather than denying it, especially in the name of something we do not know, but only believe, is possible out of time, when all the things we know point to the fact that life is transient and there are no actual transcendentals beyond life. Thus, there is a conspicuous contradiction between what we know from science and what we believe in religions. We tend to be caught in this double bind in our lives and suffer paralysis due to it, often thinking we are going to Hell in a hand basket along with everyone else, when it is precisely this thought that prevents us from doing whatever we might end up in Heaven.
Protestantism which has the belief for the most part that “BELIEF” is all that matters and actions do not matter at all in the decision as to who is saved and who is damned is particularly extreme in this respect. Action is what we can do in life to try to assure that we will end up in Heaven, and if you take that away, and nothing can be done, then it intensifies the anxiety about future transcendental states to the utmost and thus produces an extreme nihilistic situation. Catholicism at least still believes that actions matter, but unfortunately it also has traditionally believed that you can buy your way out of future suffering, and that the Priests are the ones who can relieve the anxiety by giving pardon for sins done if they are confessed, and if one has made the proper remediations.
So, in the difference between Dante and Milton there is really an impossible trap. Either you believe in action and that it can make a difference, but also believe that there are representatives of God who can pardon you and from whom you can get reassurance that your sins are absolved, OR you believe that there is no power to absolve you as in Protestantism, but get the extreme intensification of anxiety that actions do not matter anyway, and that it has already been decided what your fate will be by God. If Catholicism is nihilistic for all the reasons that Dante cites when he puts the Popes in Hell, then Protestantism is even more extreme and the break with Catholicism in Protestantism brought an intensification of Nihilism along with the freedom from Catholic dogma and the Inquisition. If it does not matter what you do as most Protestants believe, then you can do anything and that is just as nihilistic as Anarchism because moral foundations of action do not matter to God.
Both of these views led to the rape and pillage of the entire world in the name of Manifest Destiny and other colonial notions. In Catholicism it was justified by bringing true religion to savages, little did it matter we are stealing gold from them in the process, murdering them, destroying their world and sowing cultural destruction everywhere that Catholic colonialization went in the world. This colonial spirit was intensified by the Protestants who believed that their actions did not matter, and after they came back from the Entrepreneurial (Enter and Take) exploits overseas they believed that one may become “born again” and thus feel as if one is saved, regardless of what one had done in the Colonies to make ones fortune. So historically we can see that Beliefs in Transcendentals have had real world effects destroying the happiness of many though the exploits of a few good Christians who felt they were holier than thou, and had the right to convert the world to the one true faith at gun point if necessary and this is what gave Nietzsche such severe doubts concerning religion.
Nietzsche said that we must question the value of Values, and when you do that you can become a Free Spirit who makes their own values, (values ultimately come from us not from outside sources) and the values we make should support life not death, because we are living creatures engaged in the flux of evolution. Whatever supports life should be encouraged and whatever leads to death should be discouraged, and our morality should reflect that.
But even Nietzsche resorts to the idea of “Eternal” in his idea of the ‘Eternal Return’ to produce a principle for judging action. And that principle has as a criteria for judging action whether you can bear to re-experience that action myriad times. This is his equivalent to the Kantian Categorical Imperative. His idea is that life affirming actions can be re-experienced myriad times without tire, but that life destroying actions cannot be re-experienced without turning into torture. And this gives us a different way to see Heaven and Hell. Heaven is ‘eternal return’ of life affirming actions, and Hell is ‘eternal return’ of death seeking or creating actions where entropy is also considered ‘heat death’. From the Nietzschian point of view, then, Eternal Happiness is happiness in the moment from actions that are life affirming. Eternal Torture is anything in the moment that cannot bear eternal repetition by the agent. Anything that would lead to the nihilism of monotony, or anything that one in re-experiencing it would lead to the happiness of the moment souring or anything that would cause one to suffer with the victim of ones actions, because he assumes in eternal repetition that one would become one with one’s victim, if ones actions were not life affirming for both. There is a lot to say for Nietzsche’s idea of life affirmation and using the criteria of Eternal Return to combat nihilism and evil in life, because anything nihilistic would ultimately be a torture if repeated infinitely, either via boredom or suffering. The idea of Eternal Return is to use the ‘Eternal’ to reinforce experiencing the moment and the actions we perform in the present, and bringing happiness into the moment to the extent one can manage, and also to diffuse transcendental beliefs that would sap the moment of its worth and meaning as all transcendentals tend to do.
In Islamic Sufism there is a different interpretation of this problem that is very interesting. Sufism reads all of the talk in Islam about the next world of the Garden and the Fire to be about the moment in which one is living, and thus we can distinguish for others and for ourselves who is in the Garden and the Fire in every moment. It places each thing that happens in an imaginal landscape and thus creates an apocalyptic perspective in each instant that is used to generate intense meaning within the world. Every action matters in an ultimate way because it is played out in eternity in the moment that it is done. Plato called this the WorldSoul, i.e. a moving image of eternity in time. In this way the hypothesis of the ‘Eternal’ is used to reinforce what is going on in our lives and to heighten every experience so that we understand our experiences as ultimate in some sense, which they are because every act is our last act in that sense, Every moment could be our death and so in a sense this imaginal vision of the next world is like our whole existence flashing in front of our eyes. But Islam gives specific practical guidance on how to get out of the Fire and into the Garden, and if we interpret that as being applicable in every moment and not in terms of some indefinite future after death, then one gets something like the idea of eternal return, but with specific prescriptions on how to get out of the hell one is in and into the garden that is protected from that hell. This is the same effect that Hinduism and Buddhism get out of Samsara only in the Islamic view reincarnation only occurs once.
Of course, normal Islam as interpreted though Jewish (Philo) and Christian (Greek) theology has all the same problems as Christian approaches to life from the point of view of Heaven and Hell. it is important to realize that the whole idea of Heaven and Hell were not part of Judaism from the beginning and that it was an idea imported from Mesopotamia and probably ultimately from Zoroastrianism which was an extremely dualistic religion. So Heaven and Hell proper as absolutes are not Semitic ideas. And Judaism is at its root life affirming (be fruitful and multiply). In fact its word for existence itself is Life. So in some sense the more we can cling to those original Jewish roots the better off we would probably be in terms of applying the Categorical Imperative or the criteria of Eternal Return.
One of the best things I learned recently from the Teaching Company tapes on the History of Christian Theology was that each religion with its theology has its own peculiar anxieties that it produces. All the anxieties are different and they lead to different results in the world as people try to deal with those anxieties.
Here I pick on the Baptists as an example of things gone wrong. The Anabaptists believed that only the Baptism of Jesus was a true ritual of salvation, and it must be done as a consenting adult to count, and thus baptism as children did not count. The Anabaptists were hated by both Catholics and Protestants together, who both hunted them down and crucified the Anabaptists. When the Anabaptists took over cities and tried to put their utopian communist ideas into action, things did not go well under their rule, and eventually all those cities they took over were taken back. The Anabaptists who were not killed off but escaped northward became Quakers of some sort when they renounced violence. The same group arose again in England later and though persecuted did were not killed off, and eventually many of them came to America, where their religion was found to fit nicely on the frontiers because it could survive without organized churches. The good thing about the Baptist religion is that they believed everyone could interpret the Gospel for themselves and their worship meetings were full of lively discussion as various interpretations of scripture were debated openly. But as with most Protestants they believed that God had chosen who would be saved already, and recognized that for most of us Hell was the destination, and so their message was mostly about Hell and why you were going there which might have some effect on the impressionable young mind.
So for instance people who were brought up as Baptists and listened to Hellfire and Brimstone sermons when they were young and impressionable are going to have certain anxieties that no amount of thinking are going to erase, no matter how much one realizes that this is a wrong approach to life. And with Catholic, or Islamic training in one’s youth different but perhaps similar religious anxieties would be instilled. Nothing is going to free one of the religious worldview one is given in one’s youth no matter how sophisticated one becomes nor how much one thinks one has gotten beyond those primitive ideas in one’s sophisticated outlook on life that comes with education and refinement of one’s knowledge and experience, nor by understanding of religion in general as many different perspectives by which one has reconciled the mortal and the immortal standing between heaven and earth, i.e. as Heidegger says in the midst of the Fourfold.
If one has had Protestant, in particular Baptist, Hell Fire and Brimstone lectures when one is a kid one is going to think one is destined to go to Hell no matter what other religion one has adopted later. These sermons are supposed to prompt good behavior, but if behavior does not matter and only belief matters then one is basically screwed, and the result is probably ‘FREEZE’ in the Fight/Flight and Freeze responses to traumatic situations. I think many of us can attest that these religious teachings of our youth have done more damage than good in our lives. There is a dark side to Eternal Happiness, which is Eternal Suffering, that shadow of doubt haunts our lives if we were indoctrinated into that harsh and unforgiving kind of belief system very early. No amount of Belief is going to do anything about that Doubt, and no amount of Action is going to be enough to assure our being saved, and knowledge cannot help because that knowledge was not there when we were a child and we were being indoctrinated with these insidious beliefs.
When one realizes that much of what goes on in the world is driven by these anxieties over transcendental beliefs, then one comes to appreciate Nietzsche who very seriously tried to solve this problem set up by religions history in the West, which had consequences for the whole world though colonialism which was the ultimate expression of the nihilism of this Belief system. There were perfectly good belief systems out there like Buddhism for instance or Taoism that were essentially nondual that were sapped of their strength through colonialism. Now Christianity is growing fastest in the Third World (Rapidly becoming the First World, as European nations sink back into Third world status). These Third world religions are gaining popularity in the West today, but the problem is that pointed out by Jung, which is that we need to deal with our Christian origins on its own terms, and that skipping to some other belief system does not actually deal with the root of the problem, which is inculcated by our culture early on and is merely transposed into whatever personal Orientalism we are engaged in. Of course, Buddhists also had ideas of Transcendentals late in the development of Buddhism, as did the Taoists. So it is not as if these religions were any different taken as a whole. But the parts of them we are interested in are the parts that allow us to seemingly escape the traps of Christian religion. Yet, no matter how deeply we know the truth of these other ways of approaching our existence, the fundamental training that envelops us when we are young is actually what casts a pale over our lives that is palpable and haunts us regardless of what we know and what we think later in life. The only way to deal with that is some kind of Trauma therapy that reaches deep into the bedrock of the self to remove those early wounds to the Psyche when we are children.
Religion in general is the intentional instillation of Trauma in the young for the purposes of social control. The idea of Eternal Happiness is really the surface that glosses over that trauma. It is a wound that was healed over too quickly and must be reopened in order for the actual healing to occur. If not Gangrene can set in. And this is because the nihilistic opposite of Eternal Suffering always haunts that thought of Eternal Happiness and ruins our lives in the process. Essentially, the Wounds of Christ on the Cross are our own stigmata that come from the Roman swords of trancendentals piercing our immanent flesh.
Healing those wounds produced in our childhood is not easy regardless of what we know as adults. But that is the path we must endeavor to take toward health within our own worldview that rises up from within the worldview itself. Like Jung I believe that no foreign doctor is going to understand or be able to heal this illness. We see in Jung’s Red Book his own struggle with these issues. We must figure out how to struggle with them ourselves, in our own way, with resources from the tradition in which we were born. If we can heal this trauma in ourselves from ourselves, then perhaps we can do less harm to the world and begin to undo some of the harm already done, before the hothouse of Venus eclipses our still green and blue Earth.