Tuesday, June 8, 2010

Ockham Quodlibet I.4-5

In the next two questions Ockham discusses angels and physics. The first asks whether an angel is in a place through his substance. Ockham first defines place in Aristotelian terms as the terminus of the containing body of what is in place, and then distinguishes between being in place circumscriptively and definitively. The first is when part of the placed is in part of the place and the whole is in the whole place. The second is when the whole placed is in the whole place - as Christ is in the Eucharist.

So then, an angel can be in place definitively but not circumscriptively. Ockham doesn't say this, but the case seems to me to be basically parallel to the way the human mind is in the body: the angel can be in any place the way that my body is the place of my mind. An angel is not in place the way God is, for God is present both to this place and also to every other place at once, which is not true of an angel. Furthermore, an angel cannot have a point as his place, since points as places do not exist. If there were real indivisible points which were the terminus of a containing body, the angel could be contained by them, but there aren't. Furthermore, there is a maximum size of the place an angel can be present at, since he is finite and limited by nature, but Ockham makes no effort to determine what this size might be. There is no minimum-sized place, and angels can coexist in a single place. Although O. doesn't draw the connection, it seems that this implies there is no limit to the number of angels that can dance on the head of a pin. This question, however, has been resolved elsewhere.

Question five builds on four to ask whether angels can be moved in place. First he defines local motion as "the successive coexistence, without an intervening rest, of something continually existing in place through diverse places" [motus localis est coexistentia successiva, sine quiete media, alicuius continue existentis in loco diversis locis].

The reason it seems that angels cannot be moved is their impartibility and indivisibility. Wouldn't any change of place for an indivisible substance have to be instantaneous? Ockham replies that when Aristotle states that in motion you always have a part of the moved in one place and part in another, he is only speaking about things which exist in place circumscriptively; but as we just saw, angels are not in place this way, but definitively. The angel's change in place happens in accordance with the manner in which he occupies a place even at rest.

Finally, in replying to an obscure objection based on a comment by Walter Chatton, Ockham gives an interesting counterfactual argument that sounds like modern possible-worlds talk. The discussion in this section is about how many things have to exist in order to verify a proposition. The Chatton-inspired objection states that in order to verify that an angel is created by God a period of time, or at least an instant, must exist for the verification to take place. I translate the counter-argument:

Assume that first of all God creates an angel together with a book, in which the proposition ["this angel is created by God"] is written, without [creating] the world; afterwards he creates the world, along with motion and time; afterwards he destroys the world and motion and time, [so that the state of things is] as before. Then this proposition "this angel is created by God" is true before the creation of the world, and after the destruction of the world it is false; and nevertheless as many things exist after the destruction of the world as there were before creation, and nevertheless it was then true and now is false. From which it is manifestly clear that sometimes three things are sufficient to verify this proposition, and sometimes they are not sufficient.

Since this is absurd, Ockham denies that time is a necessary condition for the truth of any proposition. What does this have to do with local motion? I have to admit that's rather obscure to me.


Eric said...

Chatton's objection depends on the principle that Rondo Keele has dubbed "Chatton's Anti-Razor." Chatton thinks that if you have a true sentence, and the existence of n things doesn't guarantee the truth of that sentence, then you must posit more things until you have enough entities to guarantee the sentence's truth.

The Ockhamist view under attack in I.5 is his claim that you don't need an accident motion in order to account for motion; all that is required is the moving substance and the moved substance.

Chatton's objection is that this claim is false. Suppose that "Plato is moved by Socrates" is true. Chatton says that the mere existence of Plato and Socrates alone doesn't guarantee the truth of this sentence, since God could miraculously intervene and move Plato directly.

Ockham's reply (which you quote in part) is that Chatton's principle is faulty. At the creation of the world, the sentence in question (which Freddoso translates as "this angel is being created by God" - I don't have the Latin text before me to compare, but the difference seems important) is made true by God and the angel, but afterwards (when the angel is no longer being created), God and the angel alone don't suffice to make the sentence true. (In fact, nothing could make that sentence true, after the angel has been created.)

So, Ockham claims, Chatton's principle fails to recognize that truth values can be affected in more ways than just the mere existence of substances and their accidents. In particular, the spatial and temporal positions of the relevant entities affect truth values. (The tricky thing here is that Ockham thinks he can get spatial and temporal position without assuming the existence of points of space or instants of time. I have no idea whether he can actually pull this off.)

Michael Sullivan said...


thanks for your insights, which I found helpful.

I had the Freddoso translation once but I sold it some years ago to an acquaintance. I'm reading from the critical text. The sentence in question is "iste angelus creatur a Deo". After reading this passage again more closely I see now that I didn't grasp the point of Ockham's argument at first, and failed to note the significance of his mention of conservation (as opposed to creation) a few lines further on. Thanks again!

As for points, I'll get around to this subject in a couple of days when I do q.9. Oddly enough I was just reading Petrus Thomae on points and instants last night, so perhaps I'll do a bit of comparison.

Rondo said...

Hi, folks. I address this issue pertty directly in my new book on Ockham *Ockham Explained*, it comes up on top on an amazon.com search by title.

Or a link http://www.amazon.com/Ockham-Explained-Ideas-Rondo-Keele/dp/0812696506

There are some really intersting issues that arise, here, both about razors and anti-razors, and also about the adequacy of Ockham's account of motion in relation to the needs of the calculus. Chapters 5 and 6 deal with this all in some detail. Libraries are starting to pick it up, so you might be able to borrow it too.

Love what you are doing here,

Rondo Keele

Edward Ockham said...

Thanks Rondo for the mention of your book I was looking for something like this on Ockham.