An iPod is truly a miracle. What else can you call a square inch of glass and metal that comes alive and plays the best music available in the world? (The worst music too.)
But it's not really a miracle, is it? There is nothing supernatural about it. We know exactly where it comes from. Don't we?
Barring the existence of some iPod cult (see "Reason" by Isaac Asimov), everybody agrees that iPods come from factories. We also agree that they are designed by engineers, who apply some physical laws that apparently work well enough. If you disagree with this, you should stop reading now because it only gets worse.
Where do the physical laws come from? There was no Prophet Engineer who received the Ten Equations on Mount Volt. People figured them out, building on each other's knowledge and discoveries. For a long time now we've had institutions that helped these people work together and funded their efforts (although, to be fair, much, if not most, of human progress through history has been driven by income inequalities).
The process that produced this knowledge works pretty well. It's called "science" and its main virtue is that it resolves disagreement. The basis of science is this single sentence: "If you don't believe me, go try yourself." Unfortunately not everybody can try everything by themselves. Most non-trivial experiments require training and expensive machines. Some experiments are so complex and huge that we must pool the resources of several nations to perform them.
This is where something similar to "faith" comes into play. I, the writer, and you, the reader, with a few exceptions, don't have the tools to do carbon dating of old bones. We can only choose to trust (or not trust) the institutions that do it. But, when we trust them, it's not blind faith. We see what the institutions can produce. It's stuff that works. Take a look at that iPod again. Carbon dating is based on physical laws similar to those that govern semiconductor doping. Folks that work in these fields abide to the same principles. Since semiconductor doping obviously works, is there any valid reason to believe that carbon dating is bullshit?
What does science say about God? Not much, really. And that's the point. What we know about God was told to us by other people, and we also have a tendency to make facts up by ourselves. Most, if not all, of these facts contradict what we have discovered through science. "Intelligent design" vs. evolution by natural selection is the most common example. "Immortal soul" vs. chemical reactions in the brain is a subtler one. Our scientific knowledge cannot deny the existence of God, for some definitions of God. But it contradicts most definitions of God, including the most familiar ones. And the remaining definitions are arbitrary and pointless. God could have created the universe, but after that it appears that God has let it run by itself, because there is no evidence of any later intervention. God could be observing our behavior and give us reward or punishment after death; but not only there is no evidence of this, but there is not even a reasonable basis to decide what would constitute "good" behavior in the eyes of God.
In other words, the fact that iPods exist appears to indicate that God is a complete fabrication of uninformed and wishful-thinking humans. Or else you have to believe that there are two kinds of scientists: those who work on useful stuff, and those whose objective is to contradict what we believe about God not because it's true but because it fits their agenda.
The next issue is why we should care.
Humans are important to each other. Without society, only a few of us would survive, and not very well. We can make progress only when we agree on what constitutes progress. Believing in God is an obstacle to progress for three big reasons.
First, people can---and do---believe in different kinds of Gods. Not only that, but many of these different Gods make it clear that it is a grave mistake to believe in the others. They also have different views on what is good, with the extreme position (one that is fortunately rare, but not quite rare enough) that it is a moral imperative to kill the followers of the other Gods.
Second, believing in God often comes with following accepted leaders of a particular cult. These cults tend to be conservative and have a hard time accepting new ideas that derive from new discoveries, particularly when they conflict with their world view. This slows downs or blocks the understanding and adoption of ideas that would contribute to our well being.
Third, and this is more subtle, believing in God undermines our ability to be intellectually honest, which means striving to find and accept the truth even when we don't like it. Being intellectually honest implies refusing to hold contradictory beliefs. As we move between believing in iPods and believing in God, something has to break. This sets a dangerous precedent. When we don't have enough information about an issue to make a logical choice, we follow our instinct and emotions. This happens a lot, and not surprisingly, because the world is hugely complex. But as we acquire more information, and the logically best choice happens to become clear, it is in our interest to follow it. If we are in the habit of ignoring the logical consequences of facts we accept, and stick to following our emotions, we can act against our interest, and because we are so intermingled with each other, against the collective interest.
Therefore, we should not even passively accept that it is OK for other people to be religious. We must actively push to eliminate what has become a counterproductive relic of our cultural evolution. In other words, we should convince those that believe in God that it is wrong to do so; that in fact it is evil to do so. Not an easy task, obviously. The iPod "proof" is one possible argument. I am sure there are others.
The biggest obstacle to letting go of God is that we don't have a story that's quite as pleasant and soothing as a replacement. Most believers aren't ready to give that up without some alternative set of comforting thoughts to help them through the difficulties of life. This is the area that needs the most work, and this is where atheism can make a sorely needed contribution.