Life, of course, is not all misery--though the misery that there is, is just. We also have blessings and mercy under the rule of God's providence.
"First, think of the blessing of fecundity which was bestowed upon man before he fell." This blessing is not removed, though it is corrupted. And in this blessing of the spread of the human race, we see sin and grace mixed up together, as the image of God and the sin of man war with each other through the spread of mankind across the earth.
This teaches us that the world is not as bad as it could be, God has not completely withdrawn his blessing. "He permitted us, in punishment, to fall under the tyranny of the Devil. The truth is that the devil himself is still under God's power, since it is God... who permits that the nature of the devil should even subsist."
Part of this blessing of spreading the human race is the gift of the soul. And while our procreation is not necessarily what it would have been had we not fallen, it is still a great gift that is wrapped up in our spiritual natures.
This, in turn, teaches us that "there is a parallel between natural generation and supernatural regeneration." We see in both that God is sovereign over birth, both physical and spiritual. "And no one can reflect on this marvel without a sense of astonishment and some expression of admiration for the Creator."
We also have the gift of reason, which we see blossom and flow out from infancy over time. This good was intended to raise us above our natural states to contemplation of God, and so the capacity (if not the follow-through) is cause amazement on our parts at God's creative ability.
Even when we are not being stunned by God's grace in salvation through Christ, we should be stunned by His mercy in the "natural genius of man," including "innumerable arts and skills which minister not only to the necessities of life but also to human enjoyment." All the parts of civilization and learning--language itself--are signs of the sheer mercy and blessing of God to a fallen world.
What is true of man's virtue and mind is likewise true of our physical bodies and the natural world. In each of these we should delight in the hand of God at work, while remembering that "all these favors taken together are but the fragmentary solace allowed us in a life condemned to misery."
How much greater, then, are the blessing that will come to those of us who have believed the Gospel and been redeemed by the blood of the Lamb? How much greater will even these earthly blessings be when they are glorified in the new creation, the City of God?