Welcome back to "Doggerel," where I ramble on about words and phrases that are misused, abused, or just plain meaningless.
I'm behind on my dead tree reading: I'm only now working my way through The God Delusion, but I've gotten to a chunk of it that's relevant to this Doggerel Entry. People naturally think in terms of intention for complex systems. It's a time saver in many cases: We know a rock can roll down a hill, and most of us (I hope) don't assign any intention on its part. If it's coming in our general direction, we can make reasonable guesses about where to move to get out of its way. It's not quite the same with, to use Dawkins's example, a tiger. We'd likely be eaten by the time we got ready to examine its brain in one of our clever devices. So, rather than predict which neurons will fire, stimulating which muscles, we can just go ahead and assume it'll chase and eat us, and that we should go ahead and get to safety.
One side effect of this time saving measure is that we tend to assign motive and purpose to any complex system we have a hard time predicting. Especially if it seems out to get us. I admit it, I've yelled at a few traffic lights and videogame enemies. The ancients did the same with weather, agriculture, the stars, and all sorts of things. Science has done a lot to show us these things act under predictable physical law (though we're still working on weather to some extent).
Natural phenomena follow natural law. That's it. Intention and purpose only come into the picture when some of those natural phenomena (you and me, for example) get smart enough to have intentions. There are some natural, unintelligent phenomena that can mimic the work of intelligent, purpose-driven agents, like evolution and (artificial, but natural in that they're bound by the same laws) genetic algorithms in computers. About the only time you can be sure something has a purpose is when you can trace it back to an intelligence to come up with the purpose. So far, it's still looking like the universe as a whole is purposeless. Thinking critters like us are thus far the only creators of purpose.