What Is Sin, and What Can We Do About It?
I. What Is Sin?
Sin's story: the fall of humanity (Gen. 3)
"Evil" is wider than "sin"
Natural evil (e.g., earthquakes) differs from sin, moral evil (e.g., murder)
Sin doesn't start with God
As the privation of good, sin would not "exist" (Augustine, C.S. Lewis)
Only Jesus' life shows the true nature and depth of sin
 
II. Sin's Manifestations
The world falls too: As corruption, sin undoes creation (Athanasius)
As alienation, sin breaks humanity's intended relationships
Masacchio's Expulsion from Eden
As social structure, sin orders ways of life
As personal, sin turns us into sinners, people characterized by sin
As inordinate love, personal sin is unbelief, pride, rebellion, idolatry, sloth
As shame, sin is also pride's opposite (feminists and liberation theologians)
 
III. Sin's Spread
Sin causes more sin, but how? Two alternatives:
1. Adam's "original sin" is inherited biologically (Augustine) or legally
2. Adam's sin is transmitted socially (Cappadocians)
 
IV. Depravity: What Can We Do About Sin?
What is, and is not, compromised by sin?

Two visions of the human will, fallenness, grace, and salvation
(adapted from Alister McGrath, Christian Theology, 428ff):
Pelagius Augustine
freedom of the human will intact and able to choose either good or evil incapacitated through sin, but not destroyed
nature of sin merely willful acts against God also a disease, a power, guilt
nature of grace intact human capacity to avoid sin and choose grace; one-time forgiveness for past sins at baptism; enlightenment given by Christ's example unmerited favor, given even in producing the original choice to repent
basis of salvation personal holiness gained from forgiveness, fulfilling God's obligations, and Christ's example gracious promises of God, received through faith

Pelagius: With free will we can still choose good over evil
Augustine (On Free Will): Sin corrupts everything, including the mind
Thus through free will, people always choose evil
Outcome: The councils of Ephesus (431) and Orange (529) repudiate Pelagianism
Lesson: Where sin is trivialized, grace is trivialized (cf. Rom. 5:20)

V. The Divine Dilemma: Justice or Mercy?
Athanasius/Anselm pose a dilemma for God:
1. Mercy compromises God's justice
2. Yet justly destroying creation is a concession to evil
 
VI. Where Do We Go From Here?
The dilemma's solution: God comes, with "merciful justice"
Jesus is both the measure of sin and its solution
So Act I sets up the rest: The doctrines of Israel, Jesus Christ, and Church