To yourself of course. Have you ever told a lie Dan? Have you ever stolen anything.... no matter how small? What about look at a married woman with lust....ever done that? Tell the truth. Then you are a liar, a thief and an adulterer by your own admission.... and that's just three of the ten commandments. Is your life justified? Does it have a moral right to continually exist based on your performance? No, it is not justified .... you are a living contradiction of your own definition of "current truth" for yourself, not to mention that you cannot definitely state that it is even good or not, since in your view it must change over time.
Of course I've done things that I'm not proud of. Who hasn't? I've learned from it, and continue to progress, and therefore I feel good about myself, "justified" if you will.
As to my "current truth" that changes over time, again, and again, and again, I don't know how many different ways I have to state it for you to understand my point, and this is getting tiresome, but I'll say it again: Moral standards change for believers and nonbelievers alike, both in the individual and across generations.
What about meaning for such a life. Does it have moral value? When you are on the victum end of a big lie, a theft or an adultery, do you just reason that the perpatrator must have simply had different "social conditioning" and thus is justified for victumizing you?
No, I never said that I didn't think my social conditioning was no better than anyone else's. If somebody's social conditioning led them to believe that stealing from me or having sex with my wife is ok, then I think my social conditioning was better than his. Why? Because I value civilization, I think it is better than the law of the jungle, and values such as "don't steal" and "don't bang your neighbor's wife" are key elements of a civilized society. If somebody values the law of the jungle over the laws of civilization, then they aren't going to get very far or last very long in this world, because the emphasis of human moral development has been towards creating civilization, and laws and social conditioning are designed to perpetuate civilized life.
The truth that no one wants to admit is that the human species is fallen. It is in a condition of total depravity. It cannot know what is good or bad from any source except God. It is incredibly easy to deceive. Even when it accurately accepts something as good, it cannot be the governor of the body sufficiently enough to prevent it from doing bad. Therefore, it has no right to exist, even by its own standards much less God's.
How exactly is it that God tells people what is right and wrong? And how do you know that God has your best interests at heart? How does God determine what right and wrong is? And how do you know you haven't been deceived by "social conditioners" to believe in something that doesn't exist?
When a person becomes a religionist, he has the same problem as the atheist.... how to be sure that his notions about good and bad are authentic. This is where the similarity ends because the religionist will go on to imagine his goodness through his adherence to his religious ritual, duties, karma, whatever. Just a little investigation will reveal the hollowness of it all and especially the sin of imagining himself more righteous than his neighbor.
The atheist on the other hand lives in sort of a multi-dimensional world of ever changing morals, judgements and rationalizations based on social conditioning. But, the atheist is far more fun to go and have some beer with than the religionist, that's for dang sure!
Again, social conditioning is a factor for believer and non-believer alike. Again, I refer to my example of slavery.
The good news is that when Christ came he convicted the world of sin (we all had a hand in killing him) because none of us could trust him by our own efforts. Although we can do "some" good, there is nothing ultimately good in humans. That is why the Source of Life himself offers to live inside us and make possible that which we can only aspire to.... not to mention also a pardon for our crimes against each other and against God. The biggest people he had a problem with were the religionists. I suspect if the atheists or any other group who held that they knew how to accurately determine good/bad were there, we'd have His conviction of them as well.
Again, how can you be certain that you haven't been duped by powerful people into believing something that has no basis in reality? Do you believe that this Christ guy was really really dead as a doornail, and then came back to life? If yes, how do you know that this is true?