1. Abū Naṣr said: The principles that constitute bodies and their accidents — which are of six sorts — are of six major rankings, and each ranking embraces one of the sorts. The first cause is in the first ranking; the secondary causes are in the second ranking; the active intellect is in the third ranking; the soul is in the fourth ranking; form is in the fifth ranking; material is in the sixth ranking. What is in the first ranking cannot be many; rather, it is only one, unique. What is in each of the rest of the rankings is many. Three of them are neither bodies nor in bodies — namely, the first cause, the secondary ones, and the active intellect. And three are in bodies even though they are not themselves bodies — namely, soul, form, and material. There are six kinds of bodies: the heavenly body, the rational animal, nonrational animals, plants, minerals, and the four elements. The whole brought together from these six kinds of bodies is the world.

2. The first [cause] is what ought to be believed to be the deity. It is the proximate cause for the existence of the secondary [causes] and for the existence of the active intellect. The secondary ones are the causes for the existence of the heavenly bodies; from them, these bodies attain their substances; and from each of the secondary ones results the existence of every one of the heavenly bodies. From the highest of the secondary [causes] in rank results the existence of the first heavens, and from the lowest of them results the existence of the sphere of the moon. From each of the intermediate ones results the existence of each of the planets that are between these two. The secondary [causes] are as numerous as the heavenly bodies; and the secondary [causes] ought to be said to be spiritual existents, angels, and the like.

3. The activity of the active intellect is looking out for the rational animal and seeking for it to obtain the ultimate ranking of perfection that a human being can obtain, namely, ultimate happiness — which is for a human being to reach the ranking of the active intellect. Now that comes about only by attaining separation from bodies, not having need of anything lesser — not body, material, nor accident — for subsistence, and by always remaining at that perfection.

While the active intellect is one in essence, its rank also embraces those rational animals who have become transcendent and achieved happiness. Of the active intellect, it ought to be said that it is the trustworthy spirit and the holy spirit. It is called by names resembling these two, while its ranking is called kingship and names resembling that.

4. The principles in the ranking of the soul are many. Among them are the souls of the heavenly bodies, the souls of the rational animal, and the souls of the nonrational animals. Those belonging to the rational animal are the rational faculty, the appetitive faculty, the imaginative faculty, and the sense-perceptive faculty.

It is by the rational faculty that a human being embraces the sciences and the arts; distinguishes between noble and base actions and moral habits; deliberates about what ought to be done or not done; and, in addition, apprehends the useful and the harmful, the pleasurable and the painful. Of the rational, some is theoretical and some practical. Of the practical, some involves skill and some deliberation. By the theoretical, a human being embraces knowledge of what is not such as to be carried out at all; and by the practical, a human being becomes cognizant of what is such as to be carried out by means of his volition. By the skillful, the arts and crafts are embraced; and by the deliberative, there comes about thought and deliberation concerning each thing that ought to be carried out or not.

By the appetitive [faculty], there comes about the human appetite for seeking or fleeing something, longing for or loathing it, and preferring or avoiding it. By it, come about hatred and love, friendship and enmity, fear and trust, anger and contentedness, harshness and compassion, and the rest of the affections of the soul.

The imaginative [faculty] is what preserves the traces of sense-perceptions after they have been absent from sense and, in waking and sleep, combines some with others and separates some from others in combinations or separations, some of which are accurate and some false. In addition, among the actions and moral habits, it apprehends those that are useful and harmful, pleasurable and painful, but not those that are noble and base.

What pertains to the sense-perceptive [faculty] is evident. It is the one that apprehends sense-perceptible things by means of the five senses of which everyone is cognizant. It apprehends the pleasurable and the painful, but does not distinguish the harmful and the useful, nor the noble and the base.

5. Some nonrational animals are found to have the three remaining faculties apart from the rational one. For them, the imaginative faculty takes the place of the rational faculty in the rational animal. And some are found to have only the sense-perceptive faculty and the appetitive faculty.

6. The souls of the heavenly bodies are of a species different from these souls and are distinct from them with respect to their substances. By them, the heavenly bodies become substantial; and through them, they move in a circle. They are of a more venerable, perfect, and excellent existence than the souls of the species of animals around us. That is because they are in no way potential, not at any moment. Rather, they are always actual because their intelligibles have been continuously attained in them from the outset and because they are always intellecting them.

Now our own souls are potential at first, then become actual. That is, at first they are receptive traits disposed so as to intellect the intelligibles. Then, afterward, they attain the intelligibles; and at that point, they become actual.

The heavenly bodies have neither the sense-perceptive nor the imaginative soul. Rather, they have only the soul that intellects. In this respect, they are somewhat comparable to the rational soul. What the heavenly souls intellect are things that are intelligible in their substances, namely, the substances separate from material. Each of these souls intellects the first [cause], its [own] essence, and the secondary [cause] that gave it its substance.

7. Most of the intelligibles a human being intellects pertaining to things in material are not intellected by the heavenly souls because by their substances they are of too high a rank to intellect the intelligibles beneath them. Now the first [cause] intellects its essence, even though its essence is, in some respect, all of the existents. Indeed, when it intellects its essence, it has already intellected all of the existents in some respect because each of the rest of the existents secures existence only from its existence. Each of the secondary [causes] intellects its [own] essence and intellects the first [cause].

8. The active intellect intellects the first [cause] and all the secondary [causes], and it intellects its essence. It also makes things that are not intelligibles in their essences intelligibles. Things that are intelligibles in their essences are things separate from bodies that are not constituted by material in any way, and these are intelligibles in their substances. For the substances of these [intelligibles] only intellect and are intellected; indeed, they are intellected insofar as they intellect, and what is intellected of them is what intellects.

The rest of the intelligibles are not like that. That is, whereas rocks and plants, for example, are intellected, what is intellected of them does not also intellect. Those that are bodies or in bodies are not intellected by their substances, nor is anything pertaining to them that has the rank of substance an intellect in actuality. Rather, it is the active intellect that makes them intelligibles in actuality. It makes some of them intellects in actuality and raises them from the level of existence they are in to a rank of existence higher than what they were given by nature.

Consequently, the rational intellect by which a human being is a human being is not in its substance an intellect in actuality. It is not endowed by nature to be an intellect in actuality, but the active intellect causes it to become an intellect in actuality and makes the rest of the things intelligible in actuality for the rational faculty. When the rational faculty attains to being an intellect in actuality, that intellect it now is in actuality also becomes similar to the separate things and it intellects its essence that is [now] intellect in actuality. And what is intellected of it becomes what intellects. At that point, it comes to be a substance that is intellected in that it is an intelligible insofar as it intellects. And, at that point, what intellects, what is intellected, and intellect come to be a single thing itself in it. Through this, it becomes such as to be in the rank of the active intellect. And when a human being obtains this rank, his happiness is perfected.

9. The status of the active intellect with respect to the human being is that of the sun with respect to vision. For the sun gives light to vision so that, through the light procured from the sun, vision becomes actual viewing after having been potential viewing. By that light, it views the sun itself, which is the cause for it having vision in actuality. Moreover, the colors that were potentially seen become seen in actuality, and the vision that was potential becomes actual vision. Similarly, the active intellect provides a human being with something it traces on his rational faculty, the status of that thing with respect to the rational soul being the status of light with respect to vision.

By means of that thing, the rational soul intellects the active intellect; and by means of it, things that are potentially intellected become intellected in actuality. By means of it, a human being, who is potentially an intellect, becomes an intellect in actuality and in perfection until he comes to be in proximity to the rank of the active intellect. So he becomes an intellect in his essence after having not been like that and an intelligible in his essence after having not been like that. And he becomes divine after having been material. This is the function of the active intellect, and for this it is called the active intellect.

10. Form is the bodily substance in a body, like the shape of a bed in a bed. And material is like the wood of a bed. So form is that by which embodied substance becomes actual substance, and material is that by which it comes to be potential substance. For a bed is a potential bed insofar as it is wood, and it becomes an actual bed when its shape is attained in the wood. Form is constituted in material, and material is a subject to carry forms. For forms are not constituted in themselves, but need to exist in a subject; and material is their subject. The existence of material is only for the sake of the forms.

It is as though the first purpose were only that forms come to exist. Since they are constituted only in a particular subject, material is established as a subject to carry forms. Therefore, when forms do not exist, the existence of material is in vain. And nothing in natural existents is in vain. Therefore, it is not possible for primary material to exist devoid of a particular form. For material is merely a principle and cause in the manner of a subject for carrying a form. It is not an agent or an end, nor does it have existence by itself without a form. Both material and form are called “nature,” except that this name is more fitting for form.

An example of that is vision. For it is a substance. The body of the eye is its material, and the faculty by which it views is its form. By the two of them coming together, vision comes to be vision in actuality. And the rest of the natural bodies are like that.

11. As long as souls are not perfected and do not perform their actions, they are merely faculties and traits disposed to accept the traces of things: like vision before it views and before the traces of things viewed are attained in it, the imaginative [faculty] before the traces of things imagined are attained in it, and the rational [faculty] before the traces of the intelligibles are attained in it and they [all] become forms. For when the traces are actually attained — I mean, the traces of sense-perceptions in the sense-perceptive faculty, imagined things in the imaginative faculty, and the traces of intelligibles in the rational faculty — they then become different from the forms, even though these traces attained in the previous traits are similar to forms in material. They are called forms only due to similarity.

Those most remote from being forms are the traces of the intelligibles attained in the rational faculty. They are almost separate from material, and their existence in the rational faculty is very dissimilar from the existence of form in material. When the intellect actually reaches the point of being similar to the active intellect, it is not then a form nor similar to a form even though one faction homonymously also calls all disembodied substances forms. They establish some forms as separate from material, [that is,] not needing it and being rid of it; and others as not separate from material, namely, the forms we have mentioned. This is one of the divisions of the homonymous noun.

12. There are rankings of the forms needing material. The lowest in ranking are the forms of the four elements. And these four are in four materials. The four materials are of one and the same species. For the one that is material for fire can itself be established as material for air and for the rest of the elements. The remaining forms are the forms of bodies arising from the mixing and blending of the elements, and some are higher than others. For the forms of minerals are of a higher ranking than the forms of the elements; the forms of plants — their variance from one another notwithstanding — are of a higher ranking than the forms of minerals; and the forms of the species of nonrational animals — their variance from one another notwithstanding — are higher than the forms of plants. Next, the forms of the rational animal — namely, the natural traits it has insofar as it is rational — are higher than the forms of nonrational animals.

13. Both form and primary material are the most defective of these principles in existence. That is because each of them requires the other for its existence and constitution. For form cannot be constituted except in material. In its</