[Serious] Book reports

[GrandizerII]

The cause of the decay is the natural propensity of the particle; a part of the particle's essence is that it will at some point decay. It need not be mechanically triggered.

I appreciate your elaboration, and I have no question that ultimately quantum mechanics can fit well within the Aristotelian framework (with some modifications, I'm guessing).

That said, how would you argue for the directedness of a random behavior towards a certain final cause? If, say, in the double-slit experiment, we observe that a particle will either go through one slit or the other, and there's no specific mechanism/attribute (at least according to some interpretations) that directs the particle to go through one slit rather than the other, is this still in line with what Feser said earlier in the book that an efficient cause is directed to act on an object towards a particular final cause? Perhaps Feser would say that directedness need not be so specific as to be in only one direction, but then wouldn't Feser's objection to the Humean way of thinking about causality falter somewhat?

I guess I enjoy the angel talk because it shows cases of how different things could show the various qualities that he talks about. As he says, a thing need not actually exist for us to talk about its essence. So I don't think we have to believe in angels to take them as thought experiments. 

That said, angels are pretty different from Platonic Forms. 

I think Platonic Forms are supposed to be

~ universal
~ uncreated (in the mind of God all along)
~ without location
~ without extension (this is the same for angels -- they have location but not extension)

Angels, on the other hand, would be:

~ individual (There's only one Raphael, one Michael, one Uriel, etc. If Aquinas believed in Platonic Forms, there would be a Platonic Angel Form that exists "above" each particular angel's existence.)
~ created 
~ having location (an angel can be said to be in a certain place and not in another)

Very roughly, maybe an analogy would be that numbers are a little like Forms while particular thoughts are a little bit like angels. The number 2 is universal, uncreated, doesn't exist in any particular place, and has no size. A particular unique thought which is currently in your mind, however, is particular to you, was created by you, and is located in your mind. Neither is made of matter, but the way they exist is different.

You certainly put in more effort here to distinguish between angels and Platonic Forms than Feser did. Feser, if I still remember correctly, only brought up the universal vs. individual distinction.

Still, I guess the issue for me here isn't that there aren't distinctions in accordance with Aquinas's metaphysics, but that I have a hard time understanding how these differences manifest in reality (if somehow angels and other types of pure forms could possibly exist concretely). Your analogy makes sense because I can conceive of numbers and thoughts existing, just not in the concrete sense.

Either way, the next chapter should be fun to read, since it's all about natural theology.