@pachomius
I am talking with atheists, and from stock knowledge I know that atheists don't accept that there is order in the universe.
I'll bet that your atheist acquaintances get their ideas about disorder from a mistaken understanding of the second law of thermodynamics: that's the one that says entropy, or disorder, can only increase in a closed system.
The trouble with that law is that it was originally formulated to describe the behavior of gas molecules in a closed system, i.e. a perfect box, so that people could get a grip on how steam power worked.
Suppose I have a box full of vacuum with a divider partitioning it into two halves. If I pack a load of gas molecules into one half of it they'll be bouncing around in that side of the box, tightly packed together. Now, I remove the divider and... the gas molecules spread out to fill up the other side. Before I took the divider out each molecule only had a certain amount of room to move around in; with the divider out they now have twice as much room, so they're more spread out, and so they are more disordered. The engineer-scientists who formulated the 2nd law focused on the order-disorder that they saw in the box and worded the law in terms of disorder. Now everyone who's heard the 2nd law has come away with the idea that it guarantees increasing disorder in everything, instead of just gas molecules in a non-realistic closed system.
Personally, I see order-disorder as a silly idea imposed on the system by humans. Nature doesn't care about order-disorder. Imagine a clear box with two layers of children's building blocks in it. The top layer has 8x8=64 white cubes and the bottom layer has 8x8=64 black cubes, and you see them as 'ordered'. Now, you shake the box for a bit, then give it a couple of taps so that the cubes settle out into two layers again. Unsurprisingly, the black and the white cubes are distributed throughout both layers, and you see its contents as 'disordered'. But does the universe care if they're ordered or not? No, and to see why consider a smaller box that has 2x2=4 white cubes and 2x2=4 black cubes in it. Shake the box and let the cubes settle out. Repeat this for a while and eventually you'll get a layer of white cubes sitting on top of a layer of black cubes again. Has order arisen spontaneously out of chaos? No, the universe doesn't care how the cubes are arranged; the arrangement with a white layer on top of a black layer has exactly the same status as an arrangement with a black layer on top of a white one or a one that's jumbled up with no discernible pattern as far as you can see. The order-disorder in the box is in *your* mind, not the universe's.
So what does the universe 'care' about?
The only thing the universe seems to care about is dissipating energy as fast as possible.
In the gas box example, the kinetic energy of the gas molecules gets dissipated throughout the whole box, but because the box is supposedly a perfect closed system the total amount of energy in the box doesn't change. It just gets spread out or dissipated.
In the box of cubes example, which is not a closed system, the energy that you put into the box by shaking it gets converted into kinetic energy of the cubes, and that then gets converted into sound and heat as the cubes bang into each other and the box. The sound and heat carry the energy away from the box, thus the energy that you put in is dissipated.
Go back to before our sun formed and there was just a big cloud of hydrogen, but that cloud had potential energy due to the gravitational attraction of all those H2 molecules for each other. Gravity dissipated all that potential energy by pulling the gas into a big ball. Deep down in the center of the ball, though, a new potential energy arises. Two hydrogen atoms squeezed together have potential energy in their repulsion for each other at very small distances. This potential energy can be reduced by joining the two hydrogen nuclei together to form a single, more 'ordered' helium nucleus and releasing some of that potential energy as a photon. And so, the sun ignites.
Go back to the Big Bang and the universe is a sub-atomic sized-entity with an inconceivable amount of energy in it. The universe dissipates this energy by expanding. Nowadays, that energy (which according to the first law of thermodynamics cannot be created or destroyed, only changed) is dissipated across 13.75 ± 0.17 billion light years space, and is still dissipating.
Hope this helps to clear up why your atheist friends think disorder is the be all and end all of the universe's 'purpose'. Next time they bring that argument up, perhaps you can give them a lesson in what the 2nd law of thermodynamics is really about
