What exactly is Ghazali's argument here? Please see if you can help.

Question

The text:

These are just a few of the inconsistencies of the philosophers pointed out by al-Ghazali in the course of his disputation with regard to the eternity of the world and they could be mentioned here only very briefly, considering the space at our disposal. One further point of criticism may, however, be added for its importance in the history of modern philosophy. Prior to its origination, the philosophers hold, the world must have either been possible (mumkin), or impossible (mumtanig ), or necessary (weijib). It is impossible that it should have been impossible; for that which is impossible in itself is never brought into existence. Again, it is impossible for it to have been neces-sary in itself, for that which is necessary in itself is never deprived of existence. It follows then that the existence of the world must have always been possible in itself, otherwise it would never have come to be. This possibility cannot inhere in possibility itself, nor in the agent, nor in no-substratum, for the possible is that which is in the process of becoming actual. Hence the subject of possibility is some substratum which is susceptible of possibility, and this is matter. Now, this matter cannot be considered to have been originated. If it had been originated, the possibility of its existence would have preceded its existence. In that case possibility would have existed in itself, but possibility existing in itself is unintelligible. Hence matter is eternal and it is only the passing over of the forms to matter which is originated.

In rebutting this highly sophisticated argument of the philosophers al-Qhazali points out in Kantian fashion that possibility like impossibility is a purely subjective notion to which nothing need correspond in reality. If possibility requires an existent to correspond to it, so would impossibility require something to correspond to it, but avowedly there is no existing thing in concrete reality to which impossibility may be referred. Hence possibility like impossibility is merely a concept; the assumption of an existing substratum to which this concept may be related is to have a metaphysical jump from mere thought to actual existence and is to commit as we understand now an ontological fallacy.

Taken from here: http://ghazali.org/articles/hmp-4-30.htm#attack

Answer 1

Let's try to get straight on the argument of "the philosophers" first.

I think that what's at stake is a sentence like W: "The world exists". If I can read between the lines a little bit, my guess would be that these philosophers are trying to reconcile Aristotelianism with Islam. Aristotle believed the world was eternal, whereas Islam held that it was created at one particular instant in time. I think these philosophers are trying to find a compromise: the world isn't eternal, God created it, but he created it out of matter which is eternal and pre-existed the creation, so Aristotle got it at least partially right.

I think the gist of their overall argument is:

• (1) either (i) it is necessary that W, or (ii) it is possible that W, or (iii) it is impossible that W. (Premise)
• (2) not (iii). (Premise)
• (3) not (i). (Premise)
• (4) Therefore it is possible that W. (from 1,2,3 by disjunction elimination)
• (5) But if it is possible that W, then "the subject of possibility is . . . matter." (Premise)
• (6) But if the subject of possibility is matter, then matter is eternal. (Premise)
• (7) Therefore, matter is eternal. (from 4, 5, 6 by modus ponens and hypothetical syllogism.)

Now it looks like (1) is supposed to be just a truth of modal logic--something is either necessary or possible or impossible. This is kind of a weird way of putting it in my opinion--the opposite of necessary isn't "possible", it's "contingent". I'm not sure that's significant though.

The argument for (2) looks to be the obvious fact that the world actually exists. If it does actually exist, then it can't very well be impossible that it should exist.

The argument for (3) is more involved. The author reports them saying, "it is impossible for it to have been necessary in itself, for that which is necessary in itself is never deprived of existence" and I guess these philosophers must have also been taking it as self-evident, or as somehow contrary to faith to think that the world might have been eternal.

Premise (4) is a valid inference from (1)-(3).

In support of premise (5) they say, "This possibility cannot inhere in possibility itself, nor in the agent, nor in no-substratum, for the possible is that which is in the process of becoming actual. Hence the subject of possibility is some substratum which is susceptible of possibility, and this is matter." I have a hard time seeing what is going on here. But my best guess is that if there is some possibility, there has to be something that explains that possibility. A classic aristotelian example: If a pot does not exist, but comes into existence there has to be some matter there which is potentially but not actually a pot to be the subject of the change, namely some clay.

The sixth premise is similarly difficult. They say, "Now, this matter cannot be considered to have been originated. If it had been originated, the possibility of its existence would have preceded its existence. In that case possibility would have existed in itself, but possibility existing in itself is unintelligible. " The idea here is something like: if the matter had been created in time, then there would have been some time before which it had been created, and if there were a time before matter, then there would be a time in which potentiality existed without its being the potentiality of anything. That is to say, it would be like there being the potentiality of something coming to be a pot without there being any "clay" correspondingly which had that potentiality. There would have been a time when potentiality just had itself and that's what these philosophers find incoherent. But since the supposition that lead us to this incoherent claim was that matter had a beginning in time, then it must be false that matter had a beginning in time, which is to say that it is eternal.

The tenor of al-Ghazali's reply should now be more obvious. Al-Ghazali just wants to say that there doesn't have to be any substrate that makes a sentence necessarily or possibly or impossibly true. His claims here sound more like Quine than Kant to me, but that's neither here nor there. The important point is that he rejects the argument because he thinks that modality (necessity, possibility) is just a property of sentences or of our understanding, not a property of things themselves.

He's wrong about this, by the way, but that's a different question.