I posted a reply to you here.

Alexander wrote:

AKG wrote:

So, Scott are you essentialy saying that because the laws of physics need to be emperically tested, this entails that  just because we know about them does not entail that they exist, which would make their essence, different from their existence, and thus they would be contingent rather than necessary? If so could'nt some one argue the same thing about a necessary being as just because we know about it does not entail that it exist?

A Scholastic would probably prefer not to use the phrase "a necessary being". God does exist necessarily, but this is because He is Being Itself, which is the more fundamental way of understanding Him. To get back to your question, I think that you are correct to say that if we knew the essence of God (in whom essence and existence are identical), we would know that God exists. However, for various reasons (e.g. divine simplicity) we cannot know the essence of God except by negation and analogy: this means that we cannot grasp His existence through an a priori argument. "If you think you understand, it isn't God".

A polite reply: that, though a common reading of Thomas, is a bit of a misnomer. The Ontological Argument does not presuppose we know the essence of God (Anselm spends a lot of the Proslogion emphasising that we don't!) only that we can frame a true proposition about God i.e. that God is Perfect (lacks no perfection), a proposition Thomas himself endorses in the Summa. Indeed it would be strange if Divine Simplicity were to be considered a ‘new’ idea which scuppered the Ontological Argument as Anselm himself gives a detailed analysis and defence of it as contributive to perfection in his Reply. Indeed later scholastics like Richard Fishacre gave modal arguements from the coherance of DS to the existence of God.
 
Also there have of course been many Classical Theists who upheld Divine Simplicity without accepting the specifically Thomist account of analogical predication.
 
*Thomas might be more charitably read as claiming that we cannot know a priori that a perfect being is a possible being which is a standard drawback of the normal OA as Scotus and Leibniz pointed out. If A priori here means to know with apodictic certainty then I agree but I think one can give a good case for it.
 

Last edited by DanielCC (7/09/2015 8:07 am)

Busy day today so just time for a brief reply.

First of all, I'd like to put in my vote that cross-posting between here and Ed's blog be discouraged even though it's not positively verboten. Quite a lot of us hang out on both sites, and it will be awkward to try to carry on (or even follow) a discussion that's split between them. That's why my first reply was just a link to the answer I'd already gven on Ed's blog.

I also think that if the present question is going to be discussed further on this site, it should be taken to the "Philosophy" forum where it belongs. In that spirit I'll post just one reply here and leave it at that.

AKG wrote:

So, Scott are you essentialy saying that because the laws of physics need to be emperically tested, this entails that  just because we know about them does not entail that they exist, which would make their essence, different from their existence, and thus they would be contingent rather than necessary?

No. I'm saying, in explicating Ed's own point (with which I agree), that physical scientists themselves treat physical laws as possibly not obtaining, and therefore they themselves, on their own terms, do not regard them as necessarily obtaining.

Whatever "their own terms" may be, they (for the relevant physical scientists) certainly don't include Aquinas's real distinction between essence and existence, and I've made not so much as a hint of a reference to that distinction.

Alexander wrote:

I think both of you may be ignoring the more fundamental question of what physical laws are. Until you go into that, you may just talk past each other.

I'm ignoring it because the point about which AKG is asking concerns what physicists think physical laws are, not what Thomists (or anyone else) think they are.

That is, Ed's point was not, "Physical laws are really just descriptive summaries of the way things behave given their natures, so physicists are (or would be) wrong to think they're logically necessary." His point was, "Physicists themselves, whatever they think physical laws are, nevertheless don't treat them as though they obtain necessarily." What physical laws really are is beside that point.

To see why this point was being made in the first place, read Ed's original post. For convenience I'll quote the most relevant bit here:

Ed wrote:

[Robert Lawrence] Kuhn does not regard the fundamental laws of physics, whatever they turn out to be, as a plausible terminus of explanation. For to be that, they would have to be either logically necessary or an inexplicable brute fact, and neither supposition is credible. . . . For one thing, physicists themselves, including Krauss and Hawking, do not treat the laws of physics as if they were either logically necessary or a brute fact. For they regard such laws as empirically testable, which would make no sense if they were logically necessary (i.e. the sort of thing the denial of which would entail a contradiction). If they can in principle be falsified, then they are not necessary.

(They also, he goes on to explain, don't treat them as brute facts. I've omitted that part because it's not what the question was about.)

Last edited by Scott (7/09/2015 12:36 pm)