Calvinist theology is beset by some unfortunate terminology, which turns many would-be visitors away at the door.
One of those bits of unfortunate terminology is the expression ‘total depravity’. It is too readily taken to mean that humankind is completely and utterly wicked, and that no good at all can be found in an unregenerate heart, mind or behaviour.
In order to correct this misunderstanding, we can turn to Calvin himself, and his teaching on ‘common grace’. This doctrine says that God’s Holy Spirit not only works in believers, to effect their salvation, but in men and women generally, to restrain sin, establish a tolerable social order, and enable scientific and artistic achievement.
Calvin asserts that
In every age there have been persons who, guided by nature, have striven toward virtue throughout life. I have nothing to say against them even if many lapses can be noted in their moral conduct. For they have by the very zeal of their honesty given proof that there was some purity in their nature…These examples, accordingly, seem to warn us against adjudging man’s nature wholly corrupted, because some men have by its prompting not only excelled in remarkable deeds, but conducted themselves most honorably throughout life. But here it ought to occur to us that amid this corruption of nature there is some place for God’s grace; not such grace as to cleanse it, but to restrain it inwardly. For if the Lord gave loose rein to the mind of each man to run riot in his lusts, there would doubtless be no one who would not show that, in fact, every evil thing for which Paul condemns all nature is most truly to be met in himself [Psalm 14:3; Romans 3:12]. (Institutes, Book II, Ch III:3)
And he warns us against slighting those God-given abilities that can be found even in unbelievers…
Whenever we come upon these matters in secular writers, let that admirable light of truth shining in them teach us that the mind of man, though fallen and perverted from its wholeness, is nevertheless clothed and ornamented with God’s excellent gifts. If we regard the Spirit of God as the sole fountain of truth, we shall neither reject the truth itself, nor despise it wherever it shall appear, unless we wish to dishonor the Spirit of God. For by holding the gifts of the Spirit in slight esteem, we contemn and reproach the Spirit himself. What then? Shall we deny that the truth shone upon the ancient jurists who established civic order and discipline with such great equity? Shall we say that the philosophers were blind in their fine observation and artful description of nature? Shall we say that those men were devoid of understanding who conceived the art of disputation and taught us to speak reasonably? Shall we say that they are insane who developed medicine, devoting their labor to our benefit? What shall we say of all the mathematical sciences? Shall we consider them the ravings of madmen? No, we cannot read the writings of the ancients on these subjects without great admiration. We marvel at them because we are compelled to recognize how preeminent they are. But shall we count anything praiseworthy or noble without recognizing at the same time that it comes from God? (Institutes, Book II, Ch II:15)
…and traces such excellent gifts and abilities to the work of the Holy Spirit:-
Meanwhile, we ought not to forget those most excellent benefits of the divine Spirit, which he distributes to whomever he wills, for the common good of mankind. The understanding and knowledge of Bezalel and Oholiab, needed to construct the Tabernacle, had to be instilled in them by the Spirit of God [Exodus 31:2-11; 35:30-35]. It is no wonder, then, that the knowledge of all that is most excellent in human life is said to be communicated to us through the Spirit of God. Nor is there reason for anyone to ask, What have the impious, who are utterly estranged from God, to do with his Spirit? We ought to understand the statement that the Spirit of God dwells only in believers [Romans 8:9] as referring to the Spirit of sanctification through whom we are consecrated as temples to God [1 Corinthians 3:16]. Nonetheless he fills, moves, and quickens all things by the power of the same Spirit, and does so according to the character that he bestowed upon each kind by the law of creation. But if the Lord has willed that we be helped in physics, dialectic, mathematics, and other like disciplines, by the work and ministry of the ungodly, let us use this assistance. For if we neglect God’s gift freely offered in these arts, we ought to suffer just punishment for our sloths. (Institutes, Book II, Ch II:16)
Going back to the term ‘total depravity’: it was meant to indicate, not that humankind is as wicked as possibly can be, but that every part of human nature (mind, will, emotions, etc.) is effected by sin. A preferable term, less open to misunderstanding, might be ‘radical depravity’.