"If all of life is meaningless, and ultimately absurd , why bother to march straight forward, why stand in the queue as though life as a whole makes sense?" ---Francis Schaeffer, The God Who Is There
Who says life is meaningless? Not this atheist.
If everyone completely passes out of existence when they die, what ultimate meaning has life? Even if a man's life is important because of his influence on others or by his effect on the course of history, of what ultimate significance is that if there is no immortality and all other lives, events, and even history itself is ultimately meaningless?
Who says life has to have an "ultimate" meaning? The word "ultimate" is meaningless in this question. My life has meaning because it is my life. Whether that life means anything to you is open to question. To me, it obviously has meaning.
Suppose the universe had never existed. Apart form God, what ultimate difference would that make?
There's that "ultimate" word again. If the universe had never existed, it would make no difference to me, since I would never have existed either.
In a universe without God or immortality, how is mankind ultimately different from a swarm of mosquitoes or a barnyard of pigs?
Ultimately? Again? To a human, mankind is different from mosquitos and pigs. It matters not whether there is a deity or not. I can recognize the difference, therefore it exists.
What viable basis exists for justice or law if man is nothing but a sophisticated, programmed machine? Why does research, discovery, diplomacy, art, music, sacrifice, compassion, feelings of love, or affectionate and caring relationships mean anything if it all ultimately comes to naught anyway?
Man has created laws and systems of justice under many different belief systems. The things you mention mean a great deal to those who do them or who are affected by them. "It all" does not come to naught, "ultimately" or otherwise. Beethoven's Symphonic works have not come to naught, even though he is long dead. As far as I am concerned, once I'm dead, Beethoven is no longer relevant to me, since is have ceased to exist. I'm sure his music will be relevant to others, though, for long into the future.
Without absolute morals, what ultimate difference is there between Saddam Hussein and Billy Graham? If there is no immortality, why shouldn't all things be permitted?(Dostoyevsky)
It does not take a Christian to see the difference between those two men. One has preached Christianity and has benefitted many lives. The other has been a despot and a tyrant and has killed many people. As a human, I value my own life, which leads me to value the lives of others. As a human, I can think and make decisions on morality. Dostoevsky was asking a stupid question, for effect. He knew the answer to that question. How much Dostoevsky have you read.
If morality is only a relative social construct, on what basis could or should anyone ever move to interfere with cultures that practice apartheid, female circumcision, cannibalism, or ethnic cleansing?
On the basis of one's own societal moral values. I live in a society that condemns all of those things. I believe in the rules of my society because they make sense to me. On that basis, I condemn all those acts. Do not make the mistake of believing that Judaims and Christianity have presented a single moral stance throughout its history. It has not. All morality is social. All morality is relative.
If there is no God, on what basis is there any meaning or hope for fairness, comfort, or better times?
Hope is human. We all hope, deity or no deity. I hope for better times, but celebrate the times I am in. I hope for good health, but try to do things to continue in good health. Like all humans, I will die one day. I hope I will be remembered kindly by those whose lives I have touched. No deity is required for hope.
Without a personal Creator-God, how are you anything other than the coincidental, purposeless miscarriage of nature, spinning round and round on a lonely planet in the blackness of space for just a little while before you and all memory of your futile, pointless, meaningless life finally blinks out forever in the endless darkness?
I am nothing more than that, nor do I pretend to be. The negative words, "miscarriage, futile, pointless, and meaningless," however, do not describe my perception of my life on this planet. Those are subjective words, and do not describe my experience.