Article “Worse Than We Think – What Total Depravity Is (and Is Not) by Dr. Robert Letham, lecturer in systematic and historical theology at Wales Evangelical School of Theology and author of Systematic Theology – source: https://www.desiringgod.org/articles/worse-than-we-think#modal-3117-h5xsuc56

The doctrine of total depravity is widely misunderstood. It is almost as important to know what it does not mean as what it affirms. Moreover, we will not grasp its full import unless we see it in a wider context.

In the phrase total depravity, the word depravity refers to a corrupt nature inherent in humanity ever since the sin of Adam. The necessary presupposition on which the doctrine of inherited depravity rests is the solidarity of the human race. Without that presupposition, the doctrine does not make sense.

We are not individuals in isolation. We are part of a collective whole, rather like slices of a gigantic pizza. In the Old Testament, people were seen in connection with their ancestors from the past and their tribal connections in the present; you were A the son of B the son of C of the tribe N. Hence, when Achan sinned, all Israel sinned (Joshua 7:11, 20). Likewise, the actions of the one man Adam directly affected the many (Romans 5:12–21).

Not only did we all incur guilt in Adam’s sin, but his vitiated nature was and is communicated to all his descendants. As the Westminster Confession of Faith puts it,

By this sin they [our first parents] fell from their original righteousness and communion with God, and so became dead in sin, and wholly defiled in all the parts and faculties of soul and body. (6.2)

They being the root of all mankind, the guilt of this sin was imputed; and the same death in sin, and corrupted nature, conveyed to all their posterity descending from them by ordinary generation. (6.3)

The modifier total in total depravity denotes that sin affects every facet of our nature. It does not mean that sinners are as bad as they possibly can be or that any one person is as bad as he possibly can be. Nor does it mean that fallen humans lack a conscience or that the world since the fall is entirely miserable and incapable of making any progress or appreciating the beauty evident all around. It means that no part of the personality is uncorrupted: the mind, the emotions, and so on. In William Shedd’s words, total depravity means “the entire absence of holiness, not the highest intensity of sin” (Dogmatic Theology, 2:257).

Real and Total Corruption

In contrast, Thomas Aquinas, whose treatment of this topic had a defining effect on later Roman Catholic theology, held that original sin simply wounded human nature. He argued that it does not make us averse to virtue, although it weakens us in this pursuit and brings the penalty of death, all stemming from our inheriting Adam’s loss of original innocence. Sin stains us and makes us guilty, deserving punishment. It is like an illness, some sins being curable, others mortal (see Summa Theologiae, 1a2ae.85–87). Rome came to define corruption in purely negative terms, as the loss of the righteousness that was given by God as an addition to humanity’s naturally created condition.

On the other hand, the Reformers stressed that the depravity we inherited from Adam was real, total corruption (John Calvin, Institutes of the Christian Religion, 2.1.8). The biblical basis for their position is clear in that sin is universal (Genesis 6:5; Romans 1:18–3:20). It renders humans blind to the gospel (1 Corinthians 2:14; 2 Corinthians 4:1–6) and enemies of God (Romans 8:7; Ephesians 2:1–3), and is deceitful (Jeremiah 17:9). This sinful nature is the source of evil thoughts and actions (Matthew 15:16–20).

Blindness and Inability

In practice, total depravity means that there is no human faculty left untouched by sin, even in relative terms. The mind, as well as the emotions and appetites, is biased against God. We need renewal in the whole person. Moreover, the aesthetic sensibilities are also corrupted. The aversion of fallen people to all that reflects the evidence of the Creator in the world renders them incapable of appreciating his glory and beauty. The creation is viewed in itself rather than as the ravishing and resplendent gift of God.

Because of this, there is an inevitable distortion in humanity’s reception of God’s creation, for it is not seen as in reality it is. The joy is absent that should arise from grasping the real identity of the creation as penultimate and seeing beyond it the beauty of God. Only the renewing work of the Holy Spirit can take the scales from our eyes and turn us around to appreciate the creation appropriately, for otherwise we idolize it for its own sake or denigrate it out of spiritual blindness and indifference.

A direct corollary of total depravity is that fallen people cannot rescue themselves from their guilt and depravity. This is an ethical “cannot”; they cannot because they will not. “Those who are in the flesh cannot please God” (Romans 8:6–8), cannot receive the revelation of God (Matthew 16:17; 1 Corinthians 2:14; John 6:44–45, 64–65), cannot submit to the law of God (Romans 8:7), cannot respond of themselves to the grace of God in Christ, and cannot rescue themselves because they are covenantally dead (Ezekiel 37:1–6; Ephesians 2:1–3).

It is true that fallen people can do much good of a moral, social, and cultural nature. They can show love to family, perform acts of kindness, produce great works of art, and make major contributions to civic welfare. However, apart from regeneration by the Spirit, they cannot do these activities to the glory of God. Nor, as a consequence, can they share the exultant joy of the psalmists in the wonders of God’s works (Psalms 19, 145, 147, 148). It requires a radical change, altering the entire bias of the human will, in order to respond positively to the gospel, a change that can be brought about only by the Holy Spirit.

Hearts Made Willing

Augustine put his finger on the consequences that arise from the denial of original sin and its impact throughout the depraved mind. In Against Two Letters of the Pelagians, he lists a number of elements of the Pelagian heresy. Its denial of original sin led to their supposition that salvation is based on our own merits and so is not properly grace at all. Augustine opposed both Manicheism and Pelagianism in his saying human nature is healable, since according to the Pelagians it did not need to be healed, whereas according to the Manicheans it cannot be healed since they considered evil to be coeternal and immutable.

For Pelagianism, faith and obedience are to be attributed to those who exercise them and so any failure is due to their not trying hard enough. J.I. Packer maintained that Pelagianism is the default position of zealous Christians who have little interest in doctrine (“‘Keswick’ and the Reformed Doctrine of Sanctification”). Leaving other matters aside, this heresy eradicated Christian joy, since it encouraged dependence on the constant uncertainties of our own efforts.

The root of Pelagianism, flowing from its denial of original sin and the totality of depravity, was a focus on morality, with an assertion of the ability of fallen people to respond to the gospel unaided by divine grace. It rested on the assumption that a command of God entailed the ability of those commanded to fulfill it. Augustine argued in reply that humans respond, but we do so since God makes us willing, and changes our hearts, so that we believe freely.

In short, the reality of total depravity leaves no possibility of salvation by our own efforts. It points to our dire condition from the fall and the sovereign work of God in rescuing us. Only the Holy Spirit can change us and transform us into the image of Christ, who is the image of the invisible God. This is a cause for unbounded thanksgiving to God and delight in his grace and goodness in Christ.