There is no greater testimony for the existence of a Creator than the creation. That we exist, that anything exists, at all, cries out that God is real and that he made this world for us. If there were even the slightest difference in this universe we wouldn't exist, couldn't exist. This universe has been "fine tuned" for us to live in. This is the argument from design as I have heard it presented to me countless times. Is this true? Could the forces of our universe be any different than they are now? Is this universe actually "fine tuned" just for us?
Douglas Adams says, in one of my favorite book series, Hitchhiker's Guide the the Universe, "Space is big. Really big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space." When people first looked up at the sky and wondered what our place is in the universe we imagined that we were the center. Imagine what a crab crawling on the bottom of the ocean must think. He thinks below him is the ground and the water above him is the sky, and beyond that ... who know? What might there be that could exist beyond the sky? To a crab, his ground is always shaky and the sky is thick and murky. That is what he knows of his world. We, too, walk on land and look up through our "sky" and wonder about what might be beyond that. Is it any wonder that ancient cultures considered there to be two sets of "waters", the water below and the water above and we are merely caught in between? Gen 1:6 "And God said, 'Let there be a vault between the waters to separate water from water.'"
We thought we were the center of the universe. Eventually we realized, after much kicking and screaming, that the Earth isn't the center, but instead the Earth circles the Sun. But, that isn't all. The Sun is only the center of our little planet system, which is in a vast galaxy with many Suns. And, our galaxy isn't, as we once thought, all there is to the universe, but instead is only one of many galaxies that exist throughout the universe. Every time we think we are unique we realize, compared to the rest of the universe, we seem to hold no special place. At first, we thought there was only one planet, and we realized there were more. The Sun, that must be unique, but, then, we realized, it's no different than any other star. Then our galaxy, we realized, isn't the only one. Why do we, now, think there would be only one "uni-verse". We might find, one day, demonstrable evidence that this, too, might not be so unique. For now, that's speculation, but speculation that is based on some pretty interesting science.
Viruses and bacteria are far more abundant on our planet than we are. If the argument is that the Earth exists solely for us, wouldn't it make more sense to argue that all this exists solely for them? How arrogant of us. We think that because we have reached the level of intelligence that we now have, that we are some pinnacle of evolution? The truth is we adapt to fit the environment that we are in. No more different than water fitting into a hole in the ground to form a puddle. The hole wasn't designed for the water, nor the water for the hole. The hole existed and the water was able to adapt to fit it. That's what evolution does, when it finds a "hole" that some organism can exploit, eventually, it will be exploited. Isn't it possible that if our world was any different, than some organism would be able to fit into that different environment? As a unified culture, human existence only goes back for a few thousand years. Dinosaurs existed for hundreds of millions of years. We are simply the newest species that have adapted to fit this environment. Who knows what might exist after we have run our course?
I've never understood the argument that the forces that control our universe could be any different than they are now. This view isn't just proposed by Christians, I've heard many non-theists make similar claims. But, how could we know that? We don't really fully understand how the forces that exist are related to one another, let alone why they are the way they are. How could we make the claim that they could be different? Maybe they exist the way they exist now, because they couldn't exist in any other way. All the forces, to the best of my knowledge, are dependent on one another. If one where to be altered in some way, every other force would have some effect. At least, that's the theory. The problem is no one has yet to figure out how all the forces are unified. After we crack that nut, then maybe we can postulate about how these forces might exist differently and whether or not that's a possibility.
How do we know that the universe was designed? I know what a designed thing is. I have a computer, a television, and a car. At no point have I ever considered that these things might not have been designed. Cars don't grow on trees. Leaves grow on trees. With our current technology we couldn't manufacture a leaf if we wanted to. Leaves occur naturally. Leaves are complicated things. In some ways maybe more complicated than a car. So, it has nothing to do with complexity that makes something appear to be designed. Evolution has developed hugely complicated structures, and we can see how these structures are related to other natural structures. Our knowledge of how cars are developed and our knowledge of how leaves develop is what we use to lead us to the understanding that one is designed and one occurs naturally. If cars could develop naturally, and we could understand the process of how that happened, it would be unreasonable to claim that cars were designed. In order to recognize a designed thing we would have to compare it with something that isn't designed. Without that comparison, how would we know? In the design argument, EVERYTHING is designed. So, what do you have to compare a designed thing and a non-designed thing with?
As with most Christian arguments, this is circular logic. We assume the universe is designed, and than we use the argument that the universe is designed to claim that a designer exists. If you've already stated the universe is designed, doesn't it mean that you've already decided it is? Claims need to be demonstrated. Demonstrate the existence of a designer first, then we can go about demonstrating what may or may not be designed.