Is it impossible for god to exist?Thunderf00t, in my opinion, didn't handle the question very well. He stammers for a bit and manages to get out that its a mal-formed question, which I agree with, but after watching several minutes of both of them circle between question and the same rebuttal, I was left unsatisfied. (I should say that Thunderf00t produces excellent videos that effectively refute creationist pablum - very articulate and well researched videos; but his impromptu debating needs some work).
I suspect that T-f00t's reluctance to answer the question directly was that he knew it was a trick question in the same way that Ray Comfort employs The Way of the Master; either way he answered Hovind would then point out the inconsistency of the answer and T-f00t's worldview. Its a classic Ray Comfort move. That's the genius of posing the non-sensical question.
Before I address the question itself, let's explore the rabbit holes Hovind was trying to get T-f00t to go down by looking at the implications of each answer from a creationist perspective:
T-f00t: Yes, it is impossible for god to exist.
Hovind: Ahhh ha! As a scientist how can you categorically say that its IMPOSSIBLE for anything to exist? As you know, you can never PROVE that something doesn't exist. To say you could would imply that you know everything. Are you claiming you know everything there is to know???????????????!!!???
Hovind: Check and mate. I look forward to seeing you at our next Sunday service! lol!...or the other alternative:
T-f00t: Of course, I can't say that anything is impossible.
Hovind: Ahhh ha! So you admit that god could exist! [From here Hovind could dive into any of the countlessly dumb creationist arguments that try to use science to prove biology, geology, paleontology, physics, astronomy, or philosophy support a creationist worldview (i.e. jebus is lawd)....even though those arguments have been thoroughly debunked multiple times!So you can see why T-f00t was reluctant to give a straight answer: either he thinks he knows everything or he sets himself up to have to try to recall on the spot why any one of dozens (perhaps hundreds) of potential arguments Hovind might try to use is bogus. Tough spot to be in when you're dealing with someone that either doesn't care that his argument has been de-bunked or is to dumb to realize it.
So what is the best way to answer the question: Is it impossible for god to exist?
As T-f00t pointed out, it is a bad question. Why? Because it assumes that anyone can know the conditions necessary for a god's existence in the first place. We certainly don't have clear and convincing evidence to conclude god's existence, although a weak argument could be made for reasonable suspicion (weak because such argument really just come down to anomaly hunting rendering it an argument from ignorance). So if we can't actually establish that god exists, we can't possibly know what conditions are necessary for god to exist.
Let's think about it another way, by posing a slightly different question:
Is it impossible for life to exist?Clearly the answer is no, since Earth is filled with living organisms. So the next question is can the fundamental conditions for life on earth be sufficiently replicated, hypothetically, on other worlds? Of course. The Earth formed through natural processes which led to the emergence of replicating molecules and eventually fully formed humans.
Is it impossible to grow an apple tree?Of course not. So under what conditions can an apple tree grow? It needs soil, sunlight, water, and nutrients, all in appropriate quantities that are measurable.
Is it impossible to eat an apple?No. Under what conditions can I eat an apple? Of course, I need an apple to eat, I need a mouth and a digestive tract. Those are the conditions under which I can eat an apple.
Back to the original:
Is it impossible for god to exist?Answer: I don't know and can't say whether its possible or impossible since I don't know the conditions that god requires to exist. Saying god can exist under any conditions would lead me to ask how you know this. If you answer "because he is omnipotent", you've just assumed what you're trying to prove: that exists in the first place.
The problem with the question is that we don't have a model we can study to determine whether the proposition (god) is possible or impossible. That why it is a useless question in the first place - it could be either impossible or possible; we simply don't know (and that would be a pretty lame basis to conclude that god does exist).