Lesson 48: Quality

The Category of Quality

Every human being finds various mental states within himself through knowledge by presence, such as the states of joy and sorrow, fear and hope, pleasure and pain, attraction and repulsion, love and enmity, etc. Likewise, he perceives some corporeal attributes through his own external senses, which are often changeable, such as colors, tastes, smells, sounds, etc.

Philosophers have included all of these psychic and corporeal states and attributes in a universal concept and have called it quality, which they have taken as a genus for all of them, and defined as follows: quality is an accident which is essentially incapable of division and does not include the meaning of relation. In actuality, they have introduced it as the negation of the features of quantity and relational categories.

It appears that, disregarding disputes which generally occur about the Aristotelian system of genus and difference, quality must not be taken to be a part of the whatnesses of these various material and immaterial accidents; rather they should be considered general abstracted concepts, such as state, configuration (hay’at), and accident, which are applied in the form of accidental predication to a number of things which in reality differ.

In any case, among the categories of accidents, those which may be considered definitely and certainly to be objective accidents which possess entified objects are in the category of quality, some of whose instances are perceived through infallible knowledge by presence.

On the basis of induction, philosophers have divided quality into four types: psychic qualities, sensory qualities, qualities specific to quantity, and dispositional qualities.

Psychic Qualities

A psychic quality (kayf nafsani) is an immaterial accident which only applies to psychic substances (jawahir nafsani). Until now, no precise and complete table of its kinds has been obtained. Philosophers consider knowledge, power, will, aversion, pleasure, pain, passive states, and mental habits and proficiencies to be among the psychic qualities. They have had discussions about them which have been related for the most part to philosophical psychology, the science of the soul (‘ilm al-nafs).

As has been indicated, the most certain of all the kinds of qualities are psychic qualities with which one becomes acquainted through knowledge by presence and inner experience. Even the likes of Hume, who has raised doubts about many certainties, has considered the existence of this group of qualities to be certain and undeniable.

Among the types of psychic quality, that which has the greatest relevance to philosophical discussions is knowledge, and for this reason there will be an independent discussion of this. After knowledge, will, power, and freedom are considered, which were discussed in Lesson Thirty-Eight, and more explanations pertaining to them will be found in the discussions of the attributes of God Almighty.

Sensible Qualities

By sensible qualities are meant those material qualities which are perceived through the external senses and sensory organs.

On the basis of a view which was accepted in ancient natural science, according to which the external senses are of five kinds, philosophers have divided the sensory qualities into five groups: color and light as visible qualities, sounds as audible qualities, tastes as gustatory qualities, smells as olfactory qualities, and cold, hot, rough and soft as tactile qualities. But in modern psychology, it has been proven that there are other senses in addition to the five well-known senses which must be taken into consideration when classifying the sensory qualities.

The proof of the existence of sensible qualities outside the realm of perception is not as easy as proving psychic qualities, for knowledge by presence does not apply to them. The question may be raised as to whether what we perceive as states of material things exist in the same way in the context of the external world, or whether the soul is capable of perceiving these things within itself as a result of a chain of physical, chemical and physiological actions and reactions, while they themselves cannot be proven to exist in the material world.

In order to provide a correct answer to this question one must make use of arguments whose premises are drawn from the empirical sciences. The definitive establishment of these sorts of premises depends on the progress of the relevant sciences. For example, the whatness of energy and the relation between matter and energy are not yet known with certainty, and for this reason a definitive philosophical analysis cannot be provided for them.

The ancient philosophers did not hold that light and heat had any reality apart from the states and accidents which are perceived by the sensory organs, and in this respect they considered them to be essentially simple and unanalyzable.

However, on the basis of some views in modern physics, they must be considered to be material substances, and however much they are called energy as opposed to matter in the terminology of physics, since it is believed that matter comes into existence through the concentration of energy and turns into energy through decomposition and radiation, from a philosophical perspective, energy must be considered a kind of body. It is impossible for a body to be composed of something other than bodies or to change through decomposition into something other than extended substance (i. e., body).

The issue is not settled with this, and with further attention it becomes clear that what is perceived directly is not the substance of light and heat, but an attribute of luminosity and heat. Here the previous question may be repeated as to whether the sensible qualities exist in the external world in the same way that they are reflected in the realm of perception.

Qualities Specific to Quantities

Philosophers have also named another group of qualities as qualities specific to quantities. One group of them, such as oddness and evenness, are attributes of number. Another group, such as straightness and curvature, are attributes of geometrical subjects.

Apparently, the reason these qualities are considered to be an independent group and not sensible qualities is that they are not perceived directly by the senses.

The attributes of numbers cannot be considered to be real things and objective accidents, given that number itself is respectival (i‘tibari) and lacks an object in the external world. However, the attributes of geometrical subjects, such as the straightness and curvature of a line, or the flatness, concavity and convexity of a plane are abstracted concepts, abstracted from the mode of existence of bodies by several intermediaries.

This is especially so, given that line and plane themselves are negative limits (hudud ‘adami) of bodies without any real existence of their own, which the human mind loosely considers to be whatnesses existing in the external world. Therefore, it is difficult to consider this group of qualities as objective accidents possessing entified objects. At most they may be considered to be analytic accidents.

Dispositional Qualities

The fourth type of quality which philosophers have taken to be in the category of quality is that of dispositional quality (imkan isti‘dadi; isti‘dad, lit. preparedness), which they have defined as follows: a quality by means of which the appearance of a specific phenomenon gains preponderance in a subject.

Sometimes it is called dispositional contingency, opposed to other kinds of contingency, such as essential contingency (imkan dhati) and occurrent contingency (imkan wuqu‘i),1 because other meanings of contingency are secondary philosophical intelligibles, and non-whatish concepts, contrary to dispositional contingency, which is taken to be a whatness belonging to the category of quality.

The reason given for the entifiedness of dispositional qualities is that they have existential attributes such as proximity and remoteness and intensity and weakness; for example, the preparedness of a zygote to acquire a soul is remoter and weaker than the preparedness of a complete fetus.

The preparedness of the seed of a tree to turn into a tree is more proximate and stronger than the preparedness of the soil. If dispositional contingencies were also intellectual concepts, like the other expressions involving contingency, they would not be subject to such attributions.

In order to evaluate this reasoning, it is necessary to refer to the character of the acquaintance of the mind with the concept of disposition or preparedness and to relate it to some objective existents which have this attribute. With experience of changes in objective things, man acquires knowledge that the appearance of every entified phenomenon depends on the occurrence of specific conditions and the removal of certain obstacles, which usually takes place gradually.

For example, the transformation of water into steam is conditional on a specific temperature which is gradually reached. The growth of a plant in a salty field is conditional on the removal of harmful minerals and the provision of useful minerals and the necessary water and heat, which do not appear all at once.

Noting the causal relation and the necessity for the occurrence of conditions requiring existence and nonexistence, when we consider matter (i. e., the material cause of a phenomenon) in relation to its given actuality, if all the necessary conditions are provided and all the obstacles are removed, then it will be completely prepared and ready for the reception of the new actuality.

If even a few of the existential conditions do not obtain, or some of the obstacles are not removed, then the preparedness will be remote and weak. If only some of the conditions exist or if most of the obstacles remain, then the preparedness of the matter will be very remote and weak.

In conclusion, in a material thing which possesses the preparedness for taking on a new actuality, other than the occurrence of conditions and the removal of obstacles, no other entified thing by the name of ‘preparedness’ obtains. Rather, preparedness, or disposition, is a rational concept which is abstracted from the occurrence of conditions and the removal of obstacles. Evidence for this is that this concept will not be abstracted until one compares the previous and present situations.

In the case of dispositions, the application of expressions such as proximate and remote, intense and weak, perfect and imperfect and the like, is figurative and indicates the abundance and paucity of conditions and obstacles.

What is interesting is that Sadr al-Muta’allihin, despite following the views of other philosophers about substance, accidents and some other topics, and considering dispositional possibility as a type belonging to the category of quality, has at times confessed to the fact that the concept of preparedness is abstracted from the removal of obstacles and impediments.

Among these, is his statement in the Asfar where he says, “Dispositional possibility depends on the removal of obstacles and impediments, so that if they are all removed it will be called a proximate potentiality (quwwah qarib), and if they are imperfectly removed it will be called a remote potentiality (quwwah ba‘id).2

Likewise, in his Mabda wa Ma‘ad,3 he is almost explicit that disposition is an abstracted concept and a secondary intelligible, and what is meant by saying that it has an objective existence is that it is attributed to objective things.


From the discussions about substance and accident, the following conclusions have been reached:

1. The concepts of substance and accident are secondary philosophical intelligibles, not primary intelligibles or whatish concepts. Therefore, they should not be considered as genera of whatnesses or as whatnesses in themselves.

2. Immaterial substances include complete immaterial existents (i.e., vertical and horizontal intellects), psychic substances, and imaginal substances. Material substance is the same as corporeal substance, and if specific forms be considered substances, material substances will be divisible into two subdivisions, body and specific forms.

3. Among the concepts which are called accidental categories are: psychic qualities and sensory qualities, which can be considered whatish concepts possessing entified objectivity. Continuous quantity, which includes geometrical quantities and time, must be considered an analytic accident which refers to dimensions of the existence of bodies. Also, qualities specific to quantity can be taken as analytic accidents.

However, other types of accidents are intellectual and abstracted concepts which have no objective existence themselves as independent types of accidents, though they possess an objective source in external reality from which they are abstracted.

4. Of the nine categories of accidents, six of them are specific to material things: where (‘ayn), when (mata), position (wadh‘), possession (jidah), activity (an yaf‘al) and passivity (an yanfa‘il), and likewise continuous quantity and quality specific to it, and sensible qualities. Discrete quantities (numbers) and relations are common between material and immaterial things. Psychic qualities are specific to immaterial psychic substances.

Concepts common to material and immaterial things (discrete quantity and relation) are respectival (i‘tibari) and abstracted things, and this very commonality between immaterial and material things is a sign of their not being entified, for a unitary whatness cannot be material at some times and immaterial at other times.

Quantity is not a unitary whatness; rather it is a general concept which is applied to several whatnesses with different realities, some of which are specific to material things and others specific to immaterial things.

5. Analytic abstractions such as continuous quantities and their qualities have no existence other than that of their subjects. These kinds of accidents must be considered as mere aspects of the existence of substance, which with their own subjects correspond to a simple posit (ja‘l basit).

Objective accidents, such as psychic qualities, have a special accidental existence, and the posit of them is composite (ja‘l ta’lifi). Numbers and relational categories and dispositional qualities are intellectual concepts and they have no real posits.

6. Meanwhile, it has become known that if a concept has one of these signs, it will not be whatish:

a) being predicated of immaterial and material things equally, such as numbers;

b) Being predicated of the concept itself, like the number two, this may be predicated to two number twos.

c) Commonality between the Necessary Existent and contingent existents, such as relations.

d) Inclusion of the meaning of relation, such as all relational categories.

e) Changing with respect without an external change, such as above and below.

  • 1. Essential possibility (imkan dhati) is an intellectual characteristic for a whatness insofar as it essentially does not have a preponderance for existence or non-existence, and neither of these is necessary for it. Occurrent possibility (imkan wuqu‘i) is another intellectual characteristic for a whatness insofar as its existence, in addition to being not essentially impossible, also does not imply any other impossibility. [Tr.]
  • 2. Cf., Asfar, Vol. 2, p. 376.
  • 3. Mulla Sadra, Mabda’ wa Ma‘ad, p. 318-319.