TOTAL DEPRAVITY & ARGUMENT FROM OBJECTIVE MORALITY?

Correct of clarify me if I’m wrong, but don’t these two things mutually contradict or nullify?

If the first is true, then the second is worthless.

The unsaved are so depraved that they cannot even recognize what is good or moral (of which the objective standard is God).

Quote by CS Lewis as example:

“On the one hand, if God is wiser than we His judgement must differ from ours on many things, and not least on good and evil. What seems to us good may therefore not be good in His eyes, and what seems to us evil may not be evil. On the other hand, if God’s moral judgement differs from ours so that our ‘black’ may be His ‘white’, we can mean nothing by calling Him good; for to say ‘God is good’, while asserting that His goodness is wholly other than ours, is really only to say ‘God is we know not what’. And an utterly unknown quality in God cannot give us moral grounds for loving or obeying Him. If He is not (in our sense) ‘good’ we shall obey, if at all, only through fear—and should be equally ready to obey an omnipotent Fiend. The doctrine of Total Depravity—when the consequence is drawn that, since we are totally depraved, our idea of good is worth simply nothing—may thus turn Christianity into a form of devil-worship.”