How can Paul claim in Romans 3:9-20 that all human beings outside of Christ (cf. 15:14 for Spirit-transformed Christians) are unrighteous and “not good”? Here is a helpful clarification from Victor Lee Austin in his wonderful book Christian Ethics: A Guide for the Perplexed, in the chapter “How to Succeed as a Human Being”:
“The adjective ‘good’ functions differently than the adjective ‘red.’ If I say you are holding a red apple and that you are also wearing red socks, I mean that both your apple and your socks are the same color. If I add that I’ve caught you in your red socks stealing that red apple red-handedly, I mean that your face is (or ought to be) flush with the shame of being caught out at doing a wrong, and thus your face too shares the color ‘red.’ (I don’t mean that your hands are red with your victim’s blood; although, who knows what you had to do to get that red apple red-handedly?)
But if, to the contrary, I say you are holding a good apple and you are also wearing good socks, I do not mean that the apple and the socks have something in common. A good apple is tasty and a delight to eat; good socks are neither tasty nor a delight to eat. If I make you eat your sock it would not be because it was a good sock, nor would I be a particularly good person to make you do so. The redness of an apple is like unto the redness of socks, cheeks, and other red things. The goodness of an apple is not at all like the goodness of socks and other good things.
An apple is good, if I may risk putting it oddly, when it is succeeding at being an apple. And a bad apple is one that somehow falls short at appleness. A good sock does what socks are supposed to do, and (for instance) doesn’t have too many holes, won’t bunch up in my shoe, and so forth. If I said to you that I had a bad apple, you wouldn’t know from that information along how to picture it; you wouldn’t know what made it bad. It might be rotten on one side, or it might have a worm inside it, or it might have grown incorrectly and be too fibrous to eat. If, however, I went on to say that my apple was bad because it didn’t keep my feet warm, you would rightly turn your attention from the apple to me. You might well ask: Is Austin crazy? Has he confused the word ‘apple’ with the word ‘sock’? Perhaps he doesn’t understand English?
What all this points to is the peculiarity of that adjective ‘good.’ ‘Good’ means that the noun which it modifies is what it is supposed to be, that it is living up to its nature (or, if you prefer, its definition). A good apple succeeds at being an apple. A good sock is living up to what we expect in socks. Similarly, I say, a good human being is succeeding at being a human being. But what in the world could that mean–to ‘succeed at being human’? Do we have a standard against which to measure humanness?” (Victor Lee Austin, Christian Ethics: A Guide for the Perplexed, pp. 67-68)
Several years ago I tried to defend the historic Christian conviction that all sinful human beings–outside of Christ and apart from the Spirit–fail to be “good” along a similar line of logic. See here for my essay “On Not Being Narrow-Minded.”