I started us off by asking us the question, "Do humans have a natural desire for God?" The quick and obvious answer was, "Of course!" But I hope over the last three posts you've come to appreciate some of the complexities of this debate.
For example, while we might answer "Yes!" to humans having a natural desire for God, I think many of us also want to affirm that non-believers can experience happiness and fulfillment, and sometimes we observe a happiness and fulfillment that exceeds what find among some believers. So it seems that human nature has a logic of happiness intrinsic to its own being. As a psychologist, I'd agree with this. My entire discipline is devoted to the science of human flourishing, a science open and available to everyone, like all sciences, regardless of faith perspective.
A related impulse here, mostly among progressive Christians, is to view nature, as nature, as intrinsically good, blessed and graced. Relatedly, as I describe in Hunting Magic Eels, in an increasingly post-Christian world people are turning away from transcendent enchantments toward immanent enchantments, from the Christian toward the pagan. In pagan enchantment, the natural world is inherently sacred and holy. Again, nature is sufficient unto itself. Theologies of "original blessing" and the "cosmic Christ" make Christian arguments to reach similar conclusions.
So while we might agree that human beings have a natural desire for God, we also want to affirm the goodness of nature as nature, as whole and even blessed unto itself.
Reflecting on this, I think there can be a variety of views at this point. A person can have an extraordinarily high view of nature, while still affirming that the gift of grace takes us infinitely beyond that very high summit. The "first gift" of existence can be exceedingly gratuitous. In the Protestant tradition this is often called "common grace," a blessedness and beatitude available to everyone, believer and non-believer alike. We can imagine "common grace" to be lavish, making the possibility of human joy and fulfillment universally accessible to every human person.
And yet, as I ponder this, the greater the "first gift," the more lavish is common grace, the less pressing need there is for the "second gift" of grace. If humans can actualize and experience extreme, deep, and profound joy and fulfillment independently of grace, might that rich and abiding sense of wellness and peace be "enough"? If so, wouldn't grace become a non-essential, optional lifestyle choice? Something you could opt in for, should you be a spiritually inclined person, but not really necessary to be happy and fulfilled. You could have a rich and wonderful life without grace.
We're back here to the issues of continuity versus discontinuity. Grace assumes some "lack" in nature, the Augustinian restlessness that only God can satisfy. If the "lack" becomes too great, our view of nature becomes too pessimistic and dim. We have visions of "total depravity" and a Manichean, gnostic view of creation, seeing the material world as a place of ruin which we need to escape. Such a view also struggles with the empirical reality that many non-Christians are quite happy and secular technologies of wellness do work.
Recoiling at this pessimistic view of nature we can minimize the "lack," adopting a positive, optimistic and even graced view of creation. The more positive this view becomes the lesser the "lack," the gap between nature and grace, to the point where nature becomes whole in itself and grace becomes unnecessary and optional.
In the Catholic debates, a way to navigate these issues of continuity versus discontinuity is to think of human nature as being complete in itself yet also possessing a natural "openness" to God. An (admittedly poor) metaphor you often see used to illustrate this point is a machine with modular parts. Consider a car. A new car comes in a "base model." No fancy bells and whistles. In itself, the base model of a car is not "lacking." It's an amazing car, fully functional and whole. And yet, the "base model" is "open" to additional accessories that expand and improve what the car can do and the comfort it can give. These additions do not change the nature of the car, it remains a car, and neither do the additions presuppose that the base car was in a state of non-functionality or total ruin (as, say, a theology of "total depravity" would argue about human nature.) Might grace do something similar with nature?
As I noted, I don't know if this is the greatest metaphor. But you can sorta see what it is trying to do. We don't have to view nature as lacking to be open to the gratuitous gift of grace. That is, we don't have to look at human nature or the natural world as a bunch of wrecked and rusted cars in a junk heap. We can, rather, see them as base model cars, perfectly functional and amazing, yet open to so much more. In that much, I think the car metaphor is suggestive. But it doesn't resolve all the issues we noted above. For example, David Bentley Hart would argue that these mechanical metaphors radically miss the point that human nature is a biological organism, an integrated whole, that can't be compared to modular artifacts built up from component pieces. How could you "add" anything to an integrated whole without radically altering, or even damaging, that organic integrity?
Regardless, in these Catholic debates about the natural desire for God there is the general belief that while nature has an integrity natural unto itself it also possesses an openness to the divine, and this openness, as potential and potency, lesses the need to presuppose a "lack" in nature while also smoothing the discontinuous disjoint upon the arrival of grace. To borrow a metaphor from space flight, nature can "dock" with grace. There might not be "God-shaped hole" in our lives, but there is a sense that there is something "more" to this life, a gift existing beyond ourselves and this material frame. Less a hole in the middle of human nature than a longing for a far horizon. Nature is whole and good but is also open-ended, as possibility and potentiality, to union with God, a participation in the divine nature that leads nature to a final, supernatural end.