Ok. The three paragraphs beginning "Let me put it this way" are very clear, thank you. And I see that my previous comment was basically me repeating my assertions without further explanation, for which I apologise.

So to summarize where we are at this point, I think we agree on the following (either in reality, or for the sake of argument):
- that the First Cause exists,
- that it sustains everything else that exists moment-by-moment, and didn't just create everything else and then go away,
- that the existence of the lion and gravity are caused by the first cause, and that the existence of the unicorn and anti-gravity are not,
- that the laws of physics, along with everything else we observe, are contingent, unlike mathematics and logic; there is no a priori reason that everything we observe is not going to reverse tomororow.

I think the key difference is whether the concept of a unicorn or anti-gravity has existence independent of our minds. My position is that such concepts have existence as concepts, and only as concepts, but that concepts nonetheless are real in a sense. A concept is not an invention of the human mind, but rather is a pre-existing reality that is grasped by the human mind. Given the real existence of concepts, some explanation is needed as to why the concept of a unicorn lacks existence as a concrete object but the concept of a lion has existence as a concrete object. And the same with the concept of gravity vs anti-gravity, and the concept of things behaving according to scientific laws vs popping into existence in violation of physics. Etc.

Whereas your position is that concepts are meaningless, or somehow like 'images' perhaps, or cardboard cut-outs, and perhaps only exist in human minds? And that therefore my position makes no sense. I don't want to mis-represent you, hopefully this is fair. Again, all this links directly to reductionism, since really by 'concept' I mean something like Aristotelian forms, which I think have existence independent of the objects that instantiate them. So I think it really comes down to reductionism.

So onto that topic:

>> The behavior of water cannot be explained by considering the properties of hydrogen and of oxygen
> This... is not true.

Agh, you're quoting my sentence without the second half, which makes me sound silly and gives a false impression of what I think. The second half was "and 'combining' them in the way we would to explain the behavior of an artifact." This is the key point: that we can't mentally combine the properties of the parts to explain the properties of the whole, because the properties of the parts no longer exist.

You can perform such an exercise with an artifact. Copper in a computer behaves exactly the same as copper outside a computer. It has been arranged with other things in a certain way, and therefore the behaviour of the computer is 'weakly emergent'. You can explain the computer entirely in terms of the behaviour of its constituent parts. This is not so with hydrogen and water. Hydrogen has lost all its properties when it becomes part of water. (Of course, it has done so because it is bonded in such a way as to make water and therefore can't do what it does in the absence of said bond, but this doesn't undermine the point.) When all a thing's properties cease to exist, we can infer that it hase ceased to exist as a 'thing' in its own right, although it continues to exist in a derivative sense as a part of something else. Similarly, water's properties don't exist partially in each of its constituent elements. It's not as if H makes you partially-wet, and O completes the job. The power of making wet exists only within water as a whole. So similarly, when all of water's properties come into existence when H and O combine, we can infer that a new substance has come into existence.

Obviously we can't say that in no sense can water's properties be explained by its parts. I'm not saying that. Water's wetness can be explained by pointing at its structure. But you will be pointing at water first and foremost, and hydrogen and oxygen only in a derivative sense (because, to repeat, the properties have ceased to exist and therefore we can infer that the substances have ceased to exist as independent things).

> To use words from the book, hydrogen has many potential properties, including burning (which makes it combine with O :)) and being wet (when combined with O). These properties are actualized based on the key ideas of emergence and locality.

Hydrogen has an actual (not potential) property of being burnable. It is potentially burning and thereby ceasing to exist :-). But insofar as it's hydrogen, it can't be wet. It isn't actually wet (like water) or potentially wet. You can't do anything to hydrogen to make it wet. If something is wet, it is not hydrogen. Nor can we say that hydrogen supplies 'part of' the wetness of water and oxygen another 'part'. It is water as a whole that is wet.

Do you agree that hydrogen and oxygen lose all their properties when they become part of water, due to the bond they form? Am I being fair when I say this implies that the substances themselves cease to exist as complete entities, and continue to exist only as part of something else that is now itself the complete entity?

> Where is the circular reasoning?

Would you say a lion is particles arranged in a certain way? I'm not talking about how the lion came into existence (which I think is what you're saying with "physical laws + initial conditions = lion"). If I point at a particular lion and say "what makes it a lion?", what do you say? Many reductionists say that it's a collection of particles arranged in such a way that they're a lion. Would you agree with this? If so I would say this is circular, for the reason given in my previous comment.