Romans 1:20

Romans 1:20
For since the creation of the world His invisible attributes, His eternal power and divine nature, have been clearly seen, being understood through what has been made, so that they are without excuse.

Romans 2:14-15
For when Gentiles who do not have the Law do instinctively the things of the Law, these, not having the Law, are a law to themselves, in that they show the work of the Law written in their hearts, their conscience bearing witness and their thoughts alternately accusing or else defending them.

Question:  How does this tie in with the doctrine of Total Depravity?

Answer:  Man has a natural revelation of God, and has a God-given conscience, convicting and acquitting in matters of morality. Man is totally depraved in the sense that he cannot keep the moral requirements of the Law to its required perfection. Thus, by that perfect standard, man stands condemned before God. However, this doesn’t mean that man is incapable of a single good, moral act. A soldier falls on a hand grenade, saves his unit, but sacrifices his own life. It’s absolutely a good, moral act, but if he doesn’t know Christ, he remains morally condemned under the Law. Total Depravity speaks of our moral deficiency, and why we are in need of God’s grace, both to yield in repentance and obey His will.