One argument for for God is that, even if he's merely a creation of human imagination, he still serves some useful functions. First, by creating an imaginary parent of all mankind to dish out punishments and rewards, there's an incentive for people to be good. The world is full of personal testimony of people who will tell you they were hard-drinking, wife-beating, mother-robbing, dog-kicking scoundrels until they realized God didn't approve and changed their ways. Convicted murders, rapists, drug addicts, and congressmen emerge from prison testifying that they've found the Lord and from now on will walk the straight and narrow path, and often they do. Even if fictional, God keeps us from being up to our eyebrows in wickedness, one may argue.
Second, God offers hope. The doctors come into the room and tell you there's an inoperable cancer the size of an apple growing in your brain. Prayer might be your only source of hope. Even better, perhaps, is the hope that death isn't actually death. On the latest Mountain Goat album, there's a song with the lyric, "I won't get better, but one day I'll be free, for I am not this body that imprisons me." There are circumstances where life feels like a trap, and God is the best hope of escaping the trap. Hope isn't a valueless commodity. For instance, if you are unemployed and have hope, you will keep applying to jobs and going to interviews, increasing the odds that you will be hired. If you have no hope, you won't even bother to apply for the job that you might have eventually landed.
Faced with these tangible values provided by even a fictional God, what's an atheist to do?
Let me deal with hope first. Nothing about being an atheist eliminates hope from your life. When the doctor tells you about your inoperable tumor, you can turn to the stories of thousands of people who received similar diagnosis and went on to live fulfilling lives for years and decades. Stephen Jay Gould was told he would likely die in six months when he was diagnosed with stomach cancer, and he lived another twenty years, working right up to the end. Even if you don't believe in a God who will intervene to cure your cancer, you can believe, based on evidence, in spontaneous remissions that seem to arise at random in any given population of cancer. One might argue that placing hope in randomness doesn't seem as hopeful as placing hope in God. I think there are more lotto ticket buyers than church goers, so apparently it's not without appeal. And, for me, it removes an unintended ickiness of God-based hope. You pray, your wife prays, your children pray, and still you die. In the room next door, people pray, and the patient lives. The rather random outcomes of prayer based interventions might lead to the stress of people wondering what they did to displease God. Why weren't they worthy? Remove God from the equation, and you're left with statistics. Things happen in certain proportions, and you hope that today won't be the day your luck runs out.
Not, of course, that it all needs to be left to luck: If you believe there is no interventionist God, then perhaps you place your hope in men. Men are building an increasingly good track record in all manners of cures. God guided healing, such as we've had for most of human history, produced average life spans under fifty. Evidence based healing, where humans have studied the functions of the body and the origins of disease to ever greater levels of understanding, is populating our world with octogenarians. Suppose I told you that, twenty years from now, you would go into a hospital and be told you have a tumor. Would praying now be the best strategy for dealing with it? Or would donating money to cancer research and building your financial resources to allow for top notch health insurance be a better strategy? Going back to the unemployment example, are you more likely to get a job staying at home and praying for one? Or going out and filling in applications? Placing hope in God seems like a strategy that might limit your hopeful outcomes. Placing hope in your own actions, and in the actions of your fellow humans, seems like it might increase your odds of hopeful outcomes.
But, of course, there's the point where all hope is lost. The tumor has killed you. Bluntly, I don't think, at that point, hope matters to you in the least. I don't think you are you any more. Still, isn't it useful for the survivors to have hope that they will one day be reunited with you? I suppose. But, as someone devoid of this hope, I can tell you that I don't miss it. For me, the value is in a person's life, not their afterlife. And, if you want a person to survive after they are gone, the human brain is equipped with this wonderful thing called memory. When Laura passed away, I'd find myself wondering what she would think of certain choices I was making in life. When I selected my new house, I wondered if she'd like it. Luckily, her opinions on houses weren't a mystery to me. We'd sat and watched home improvement shows side by side for years. I think she would have approved of my choice of a cosmetically impaired dwelling that was structurally solid. Your loved ones can have an afterlife of sorts as you carry them with you in your memory and still consider them as you make your decisions in life. If you live well, and try to make a difference in the lives of others, then you can have hope that, when you're gone, you at least won't be forgotten.
Which leaves us with the argument that God is useful as a source of morality. The evidence that some people embrace God and go on to live lives that benefit mankind as a whole is incontrovertible. This is the "heads" side of the God-based morality coin. The "tails" side is that there's a lot of harm done in God's name as well. People strap on dynamite vests and blow up buses, or pull out a gun and start gunning down fellow men. Doctors get murdered in cold blood while sitting in church pews. By the millions in some nations, women are kept illiterate and treated as property. In our own nation, it wasn't so long ago that prominent Christian voices celebrated AIDS as God's judgment on homosexuals. Today, fundamentalists actively attempt to squelch the teaching of evolution, fearing that Darwin is dangerous to the human soul. The danger of having an imaginary God as the font of morality is that it leaves morality in the hands of human imagination.
I would argue that it's much safer and more beneficial to strip God out of the moral equation and base our ethics on reason. Altruism is an excellent strategy for advancing the interests of you and your loved ones. The world is full of problems that can be solved by humans working together. Maybe some people need God to tell them to heal the sick, feed the hungry, and give shelter to the homeless. But, these things are good even in the absence of God. Just because I'm an atheist doesn't mean I want to see people suffer. I'm surrounded by people I love who suffer misfortune. Even if I'm a selfish bastard who sees nothing beyond my immediate friends and family, among those friends and family I have people who are sick, people who are unemployed, people who are disabled and disadvantaged. It's in my own interests to work to mitigate the sources of human suffering. I don't need God to tell me I don't want to lose any more loved ones to cancer in order to drum up money for cancer research.
If we wish to heal the sick, feed the hungry, and clothe the poor, I would argue that we can accomplish more by focusing on science than on God. Prayer probably won't cure your cancer, but surgery and chemotherapy have a real shot. Praying for rain might not increase your crop yields, but America produces more food than we can eat thanks to our studies of genetics and the engineering prowess we've shown at bringing water to deserts. As for clothing the poor, we've produced such a surplus of clothing in this country that there are probably 60 billion shirts to clothe the 6 billion people on the planet. Involuntary nudity just doesn't seem to be a major source of human misery anymore.
Mankind is capable to doing good without God. I would argue we've been doing so since we first started walking on two legs. Letting go of God as a source of goodness seems to me to be a natural part of growing up as a species, just as letting go of Santa Claus as a rewarder of good behavior is part of growing out of childhood. The question we should be asking ourselves isn't, "What would Jesus do?" It's "What should I do?"
Right now, I should go eat some lunch.