We have thus far taken up the discussion of three kinds of immaterial substance and one kind of material substance, and we have established their existence. However, we previously reported that the Aristotelians held that corporeal substances are composed of two other substances called matter and form, the former being the aspect of the potentiality of bodies and the latter being the aspect of the actuality of bodies. We shall now review this theory.
Before anything, we must bear in mind that matter, in the sense of the ground for the appearance of a new existent and that which receives its actuality, is accepted by nearly all philosophers, as, for example, water is said to be the matter for steam, soil for plants and animals, and grains and pits for their plants.
An existent which is the matter for other existents but which does not itself appear from some prior matter, in technical terms is said to possess ‘original existence’ (wujud ibda‘i) and to be without need of a material cause, and it is called the ‘matter of matters’ (maddat al-mawadd) or prime matter (hayula ula).
The difference of opinion between the Aristotelians and others is over whether prime matter is a substance possessing actuality which can be considered a kind of corporeal substance, or is a pure potentiality without any kind of actuality whose only property is the ability to accept corporeal forms.
The opinion of the Aristotelians is the latter, and this was also accepted by most of the great Islamic philosophers, including Farabi, Ibn Sina and Mir Damad. In many instances, Sadr al-Muta’allihin has followed the same line, but in some cases he called hayula a ‘privative thing’ (amr ‘adami) and in some cases he referred to it as a shadow which the intellect considers for corporeal existents, but which does not have true existence, as the concept of ‘shadow’ is abstracted from weak luminescence and has no existence beyond that of light.1 There are also some scholars who consider it incorrect to attribute the above-mentioned position to Aristotle.2
On the assumption of the existence of prime matter as a substance lacking actuality, it would seem inappropriate to consider matter and form alongside bodies all equivalently as kinds of substances. Perhaps it would be better if matter and form were considered to be two kinds of material substances, with the explanation that prime matter is inseparable from corporeal form, and that the combination of them is called ‘body.’
The main problem is that the existence of a substance which essentially lacks any kind of actuality cannot be established, and it seems that, with regard to this problem, the correct position is that of Shaykh al-Ishraq, ‘Allamah Tusi and other philosophers who have denied the existence of this sort of substance.
With the denial of prime matter as a substance lacking any sort of actuality, no room remains for establishing the existence of another sort of substance which is the first form for prime matter and that which grants it actuality, for according to this view, which is attributed to the Platonists, the first matter is a substance possessing actuality, but which is not composed of matter and form.
However, new forms occur in it either alternatively or simultaneously, such that a specific elemental form appears in it, and with its removal, it is replaced by another elemental form. However, the elemental form comes into existence simultaneously with the mineral form or vegetable form, and altogether they are incarnated in the substance of the body, that is, their parts correspond precisely to one another.
However, through all these alterations, the body always remains as a substance which possesses actuality, despite the denials by some philosophers that the new forms are substances. These philosophers only accept them as accidents for the body.
Given the denial of matter without actuality, and the acceptance of the forms of species, as kinds of substance, corporeal substances may be divided into two general kinds: one is that of a substance which does not need a location at which to be incarnated, and this is the same as body; the other is a substance which needs another substance to be incarnated in it and impressed in it, and this substance is the form of a species, such as the elemental, mineral and vegetable forms.
However, with the denial that these sorts of forms are substances, the corporeal and material substances will be confined to bodies. This seems to indicate the difference between primary and secondary substances in Aristotle. The primary substances are not incarnated, only the secondary ones are.
The Aristotelians, who believe in prime matter as substance devoid of actuality, have offered for their position two arguments which were originally close to one another: one of these is called the ‘proof from potentiality and actuality’ and the other is called the ‘proof from union and separation.’ They may be summarized as follows.
There are transformations in bodies which are unions and separations, as well as substantial and accidental changes; for example, a continuous unified body may be transformed into two separate bodies, water changes into steam, the seed of a tree changes into a tree. Without a doubt, these various changes do not take place in such a way that the first substance is completely obliterated and one or more other existents are brought into existence from pure nothingness.
Rather, certainly something from the prior existent remains in the later existent. However, that which remains is not the form and actuality of the prior existent; hence there is no other alternative but that another substance exists in them which preserve the existential relation between them. This in itself essentially and necessarily must have no actuality, and for this reason, it accepts various sorts of actuality.
In this way it is established that there is a substance which has no actuality, and which is characterized by the acceptance of forms, and, in philosophical terms, it is called pure potentiality. In other words, every corporeal existent possesses two aspects: one is the aspect of actuality and the possession of properties, and the other is the aspect of potentiality and privation in relation to future actualities.
These two aspects are different from each other, and so, every corporeal existent is composed of two different objective things. And since it is not possible for the existence of a substance to be composed of two accidents or of a substance and an accident, there is no other choice but that they must be composed of two substantial parts, one which is the aspect of actuality, and the other the aspect of potentiality.
This argument can also be put in the following form, or the following may be considered as another argument. It is possible for all bodies to change into another kind of body, such as the change of one element into another or the transformation of one or more elements into minerals, vegetables or animals (potentiality and actuality).
Likewise, all bodies have the possibility to be changed into two or several other bodies of the same kind (union and separation). This possibility for change and transformation is a kind of quality which is called the ‘quality of preparedness’ (kayfiyyat isti‘dadi) or ‘possibility of preparedness’ (imkan isti‘dadi). This is capable of intensity and weakness, perfection and deficiency, as the preparedness of a fetus to change into an existent which possesses a spirit is greater than that of a zygote.
This accident needs a substantial subject which cannot be considered to be a substance possessing actuality, since this substance has to have the possibility for the appearance of this quality, and the supposed possibility will be another quality dependent on a third possibility, and likewise to infinity.
This implies that in order for any existent to be transformed into another, and for the appearance of every new substance or accident infinity of accidents must occur each of which has temporal priority to another. Hence, it is inevitable that these accidents must be borne by a substance which is the potentiality, possibility and preparedness itself and which has no sort of actuality at all.
The mentioned arguments are not firm enough, and all of them are more or less controversial. However, since the pivotal concept in all of them is the concept of ‘change,’ we would do well to provide a brief explanation of it, although a more detailed discussion will come under the topics of change and motion.3
Change and transformation may be imagined in a number of forms. Of those relevant to this topic, the following are the most important:
1. Accidental change, such as the change of the color of an apple from green to yellow and from yellow to red.
It must be noted that according to philosophers such as Shaykh al-Ishraq, changes of species are of this sort, for they considered specific forms to be accidents. Likewise, according to modern physicists, the change of water into steam and vice versa are sorts of gathering together and separating of molecules, not a sort of substantial change.
2. The appearance of a new substantial form in matter, such as the appearance of vegetable form in soil, according to the position of the Aristotelians who consider specific forms to be substances.
3. The obliteration of a temporally contingent substantial form from matter, such as the change from vegetable to soil, according to the Aristotelians.
4. The obliteration of a previous substantial form and the appearance of another substantial form, such as the change of an element into another element, according to the Aristotelians.
5. The substantial attachment of an immaterial thing to matter without being incarnated in it (for incarnation is characteristic of matter), such as the attachment of spirit to body.
6. The cutting off of the above-mentioned attachment, such as the death of an animal or man.
By attending to the above classification, the weakness of the first argument becomes clear, for if change is related to accidents of the body, corporeal substance will be preserved with its actuality, and there will be no need for the assumption of a substance without actuality. Likewise, if there is a sort of attachment of the soul to the body, or its detachment (the fifth or sixth cases) the substance of the body with its own actuality remains.
Also in the second and third cases, in which a new substantial form is incarnated in a body or is separated from it, the previous substance is preserved. It is only in the fourth case that it is conceivable that with the obliteration of the previous form, a substance possessing actuality does not remain; hence, the thing which is in common between them is a substance which lacks actuality.
But we must remember that according to the philosophers, the corporeal form is never corrupted or obliterated, and if the existence of prime matter were also established, it would persist along with the corporeal form (regardless of substantial motion, which will be discussed in its own place). With regard to this point, a question that may be posed is, what rational objections would arise if body is considered a simple substance (i.e., not composed of matter and form) in which another form is incarnated or from which another form is detached?
Perhaps the second explanation may be considered as the answer to this question, that is, body with its own actuality cannot take a new form, but it must possess another part whose essential property is receptivity, and essentially requires no actuality.
The second explanation is based on the notion that the aspects of potentiality and actuality are two entified aspects, each of which has specific objective instances. Since the existence of a body cannot be considered to be composed of two accidents or one substance and one accident, there is no other choice but that they must be considered to be composed of two substances instead of these two aspects.
This notion is debatable, for the concepts of actuality and potentiality, like other fundamental philosophical concepts, are secondary philosophical intelligibles, which are abstracted by the intellect with a specific attention.4
In other words, when we take two corporeal things into consideration, one of which lacks the other (as the seed of a tree lacks the fruit of the tree), but which can come to possess it, then the concept of potentiality or receptivity is related to the first existent, and when it comes to possess the other, the concept of actuality is abstracted from it.
Hence, these concepts are abstracted concepts, which are obtained by the comparison of two things, and they do not have entified instances. There is no reason to consider the aspects of potentiality or receptivity to be entified things on the basis of which the existence of a substance or even an accident may be established, the whatness of which is the whatness of potentiality and receptivity.
Likewise the establishment of the causal relation among existents does not require that there be an existent whose whatness is being a cause or being an effect. This is another example of how first and second intelligibles are confused.
It is to be concluded that when a corporeal substance is compared to another substance or to an accident which is capable of being incarnated in it, it is called ‘potential’ (bil quwwah) in relation to this incarnation, but this does not mean that it possesses an objective part called ‘potentiality.’
Secondly, the second premise may be disputed, for it is possible that one may consider the objective existence of a body (not its whatness) to be composed of substance and a number of accidents. Especially, according to the position of those who consider accidents to be aspects and levels, of the existence of substance. Hence, supposing that each of the two aspects of potentiality and actuality possess objective instances, one can consider the instance of the aspect of actuality to be corporeal substance and the instance of the aspect of potentiality to be one of its accidents.
The third explanation also has two basic premises. One is that the possibility of preparedness is a kind of objective accident and is a whatish concept. The other is that the characterization (‘urudh) of this accident requires potentiality and a prior possibility, and hence in order to avoid an infinite regress a substance should be posited which itself is the very potentiality, possibility and preparedness.
This explanation is also flawed, for, first of all; preparedness is an abstracted concept which cannot have entified instances. For example, to say that the seed of a tree has the preparedness to turn into a tree means that the seed of the tree has the preparedness for turning into a tree, and if water and warmth and the other necessary conditions obtain, gradually it will develop and roots, leaves and branches will appear. So that which is entified is the seed, water, warmth, etc., but there is no additional entified existent by the name of ‘preparedness,’ and consequently, preparedness cannot be considered a kind of objective accident.
Secondly, on the assumption that preparedness is a entified quality, one may consider the first preparedness to be the effect of corporeal substance. In this way infinite regress may be avoided without need for positing a substantial potentiality (matter lacking actuality).
There is another problem with this position, which will not be mentioned in order to avoid prolonging the discussion. We merely indicate that being an existent corresponds to being actual, and moreover, they are in truth the same.
Hence, basically the supposition that an existent lacks actuality seems to be incorrect. The assumption that matter obtains actuality only in the shadow of a form is not coherent with the essential property attributed to matter of lacking actuality and being pure potentiality.
Perhaps it will be said that the pure potentiality of matter is like the essential possibility of every whatness which is inseparable from it. At the same time, in the shadow of causality, it becomes necessary ‘by another.’
However, it must be noted that the essential possibility of a whatness is a purely intellectual attribute which has no objective instances, as whatness itself is a respectival concept. But in the case of matter, it is assumed that this is an objective substance whose existence is pure potentiality. Perhaps it is for this reason that Sadr al-Muta’allihin called prime matter an intellectual and privative thing (amr ‘aqli wa ‘adami). (Take note.)