I agree that 2+2=4 and God cannot change that. It cannot possibly be otherwise, given what 2 is, what 4 is and what addition is. But the physical laws of the universe are not like that. They might have been otherwise. Not only that, but theoretically, they could logically change to being otherwise at any point. The fact that they have behaved predictably in the past in no way implies, in and of itself, that they will continue to behave predictably in the future. There is nothing, theoretically, from causing mass to start repelling mass once we hit the year 2025. We can both conceive of that concept. (Appealing to probability won't help you here since probability assumes that the future will be like the past.) Similarly, it is logically possible for things to happen that violate the laws of physics, such as a unicorn popping into existence from nowhere. There are an infinite number of things that could logically happen but do not. But only certain concepts have ontological being. These are: lions and not unicorns, laws of biology rather than sudden appearances of animals, etc.

It is not logical to appeal to the laws of physics in order to undermine what I'm saying, since (to repeat myself) these are as contingent as anything else. We can conceive that the laws of physics might have been otherwise, that they might change at some point in the future, or that they might not govern every event in reality. These concepts are logically possible. So are multiverses where the laws of physics are different. Therefore, the laws of physics are contingent, not necessary like mathematics.

It therefore follows that, if the Proofs successfully establish the existence of the First Cause, then said Cause must be causing some concepts to exist, and not others. There is nothing in the concepts themselves that make one exist, and the other not-exist. Choice is the ability to bring about effect A xor effect B, where A and B contradict. Therefore there is something on the part of the Cause that is causing one to exist, and the other not. And this obviously implies will on the part of the Cause. (Again, Feser and I are talking about the First Cause causing existence from instant to instant; not about looking back in time to what brought the universe into existence in the first place.)

Obviously the natural sciences (physics, zoology, etc) give us true information about the lion. For example, part of the concept of being a lion is that it needs food to continue its existence; that it is made up of cells that behave in a certain way; etc etc. And the details of all this could fill libraries. This is uncontroversial. But the natural sciences cannot provide a complete explanation of the lion's existence and the unicorn's non-existence, because (among other reasons) the the natural sciencse themselves are one concept rather than another, and because the need for things to 'obey' the laws of natural sciences is itself a concept that exists, etc. So your reference to biology, zoology, etc, while true, does not undermine my point. It is an explanation -- thus far we agree -- but it is a partial explanation of existence, which can't explain why some concepts exist and not others.

As for reductionism, hopefully you're happy with my definition (that everything's behavior can be explained in terms of my constituent particles). In effect, this would mean that natural objects are like artifcats. Consider an artifact like a computer. It's possible to explain how a computer works by explaining the behavior of its component parts, and then referring to their arrangement. For example, copper behaves a certain way, the plastic in the PCB behaves a certain way, the silicon in the ICs behaves a certain way, the electrons passing through the copper, silicon, etc behave in a certain way, etc. And then these things are arranged in a particular structure, and the combined behavior of all the parts gives us a computer. Obviously the same is true for a car, or a house, or whatever artifact you care to list.

Reductionism basically says that natural objects are like this as well. But this is false. Consider water, made up of H and O. Now hydrogen is a gas at room temperature, it burns with an invisible flame, it combines with nitrogen to form ammonia, with carbon to form methane or any number of things, it has one electron 'orbiting' one proton, and so on. All these things are properties of hydrogen. It is by the existence of these properties that we know hydrogen is present. Now, obviously, none of these things are true for water: literally everything I've listed is false. Certainly, hydrogen is present as a part of water -- don't get me wrong! But everything indicating the presence of hydrogen ceases to exist once it becomes part of water: an entirely new set of contradictory properties take their place. The behavior of the hydrogen has changed completely. And the same is true for the oxygen. The behavior of water cannot be explained by considering the properties of hydrogen and of oxygen, and 'combining' them in the way we would to explain the behavior of an artifact. In an artifact, the parts are unchanged, they just happen to be arranged in a certain order. In a natural thing like H20, the parts are completely changed to adapt to the whole of which they are part. So an artifact is the sum of its parts, but a natural thing is not.

You can consider a similar thing with a lion. A lion's liver, or eye, or paw, only acts like a liver/eye/paw while it is part of the lion. If you tear it out, its behavior fundamentally changes (it stops being a liver and becomes a lump of rotting flesh). So similarly, a lion cannot be said to be the sum of its parts. Rather, its parts can only be understood in terms of the whole of which they are part.

Therefore, empirically, it is false to think of every natural thing as the sum of its parts. Rather, the parts are derivative of the complete object, which is fundamentally one object. This is true for molecules, rocks, plants, animals, and human beings, along with any number of other things.

That's one reason reductionism is false. A second is that reductionism says that objects like lions are nothing more than particles arranged in a certain way. But the only way it can define this 'certain way' is by referring to a real lion. Sure, it can describe the 'certain way' in great mathematical detail, but ultimately it will be describing a lion. Reductionism is therefore circular. The only way out is to say that the lion doesn't really exist, and that it's a concept that we 'impose' on the particles. But there's no good reason for thinking this, and obviously, claiming that lions don't really exist can lead you into some pretty weird and anti-rational territory :-)

Thirdly, there is no actual good reason for thinking that things are nothing more than the sum of their parts. The fact that one can explain a thing's behavior according to its parts in no way implies that it is 'nothing more' than those parts as they would exist separately from that thing. Methodological reductionism does not imply ontological reductionism.

> Just from the proofs, do you think you will still strongly take a loving caring God who actively created and sustains this universe to be true?

To answer very, very quickly: I'd believe in the qualities that Feser outlines. But not 'loving caring' in a personal way. Not in the sense that one would hope a good parent to be. Only in the sense that God wills that which is good for everything. We'd know of His existence, but He would be very distant and unknowable. The Trinity and the Incarnation are complete game-changers in this regard, which is why they are the absolute foundational teachings of Christianity :-)