So, once again, the only way to assert there is no possibility of intelligent design...is to assert there is no possibility of a GOD.
If my thinking is wrong on this, I'd like to hear where it takes the wrong path.
People have preconceived notions of God... how he'd have to behave if he exists and so forth. Part of the problem is that God does not appear to obey any such precepts. As far as I can tell from reading, God operates entirely within the laws of physics; if you want violations of phyical, mathematical, and probabilistic laws and particularly if you want them in wholesale lots, you need to be talking to the evolutionites, they specialize in that sort of thing.
The most major proof/demonstration of the basic existence of God is simply the fact that the only other option, evolution, has been overwhelmingly disproved within the past century or thereabouts.
The fruit fly experiments in the early decades of the 1900s (basically a deliberate test of the idea of macroevolution) should have been the end of it. Fruit flies breed new generations every other day so that running any sort of a decades-long experiment with fruit flies will involve more generations of them than there have ever been of anything resembling humans on our planet. Those flies were subjected to everything in the world known to cause mutations and the mutants were recombined every possible way; all they ever got were sterile freaks, and fruit flies. The results were so unambiguous that several prominent scientists publicly denounced evolution as a result.
The failure was due to the fact that our entire living world is driven by information and the only information there ever was in the picture was that for a fruit fly. When the DNA/RNA information scheme was discovered, even if the fruit fly thing had never happened, evolution should have been discarded on the spot. But GIVEN the fact of the fruit fly experiments, somebody HAD to have thought to himself "Hey, THAT'S THE REASON THE FRUIT FLY EXPERIMENTS FAILED!!!!!!"
If living things were composed of clay and simple stuff you might could still argue for evolution, but when you're talking about information schemes and gigantic complexity, that doesn't work.