Case in point: a theist wrote to me:
Current observations indicate that order and consistency (e.g., "design") can arise from intelligence or from undirected events (e.g., Mandelbrot patterns, chance).
Given those observations, is there any reason to assume that the design of the universe more likely arose from intelligence (theism/deism) or from undirected events (atheism)?
First of all, just because you have two possible events doesn't mean that the two must be equally likely. Some people actually play the lottery this way. They reason: "I either win or I don't. So my odds of winning are 50%." Wrong. The odds of winning the Texas jackpot are about 3*10^-8, which is way WAY less than 50%. Likewise, even if we grant that the existence of God is "a possibility" that doesn't necessarily mean that the probability is any more that 10^-googleplex. Just about anything that you make up off the top of your head COULD turn out to be true, but probably isn't.
But explaining logical fallacies can be difficult when dealing with somebody who is convinced that he's got an airtight case. So I responded with:
Current observations indicate that people can be killed by machine guns, or by things that are not machine guns.
Given those observations, is there any reason to assume that Julius Caesar was more likely killed by a machine gun, or by a non-machine gun event?
He wasn't buying it:
We know with reasonable certainty that there were no machine guns during Caesar's time, so the latter is best assumed.
So what is it that you know about the origin of the big bang that makes your analogy relevant?
But I said:
We certainly do not know that. All we know is that we don't KNOW of any machine guns in Julius Caesar's time. Yet we know that it is possible for machine guns to exist. So what is your proof that machine guns did not exist then?
Another thing we know is that it is much easier to kill someone with a machine gun than without one. Given the reasonable belief that Julius Caesar was killed (rather than dying of natural causes), isn't it fair to say that if there is even a small chance that machine guns existed, then it is at least equally likely that they were used as that they were not?
Why is assuming the existence of something complex, like a machine gun, not plausible to you, when it can be used as a handy explanation for Julius Caesar's death?
What's wrong with this logic? As far as I can tell, nothing. Oh sure, it sounds stupid, but I think it's just as solid as the first cause argument.
The problem with postulating "an intelligence" as the answer to "where did the universe come from?" is that as far as we know, there wasn't any intelligence available at the time. Intelligence in the world we're aware of universally requires some kind of brains, and the brains that we know didn't just happen to exist; they are the end result of billions of years worth of painstaking evolutionary processes.
Could there have been a cosmic super-brain, long before the brains that we know of came into existence? Sure, anything's possible. And Julius Caesar could have been killed by a machine gun.
But you know, I think he probably wasn't anyway.