The Nature of Body in Avicenna’s Metaphysics

Also, see:
God as necessary and First existence
God's way of knowing

Introduction

Ibn Sina, commonly known in the West as Avicenna, was a Persian philosopher (and very erudite in a vast array of professions), who lived during the middle-phase of the so-called Islamic Golden Age. Philosophically, however, his metaphysical concerns were far more closely related to Aristotelian philosophy than to the Islamic tradition of interpreting the Qu’ran. Here, I want to elucidate this statement by focussing on his (Aristotelian) treatment of the nature of body in three ways. First, we will assess Avicenna’s treatment of the three-dimensionality of body. Second, we will deal with the notion of divisibility of bodies and the role this view takes in his general criticism and refutation of atomism. Thirdly, Avicenna’s conception of matter and form with regard to natural bodies will be discussed. Through these three arguments, we want to arrive at an oversight of Avicenna’s analysis of body qua body that serves as preparatory work that allows him to embark on his metaphysical inquiries. (1) A secondary objective in this analysis is to demonstrate that a reliance on the Islamic holy scripture when discussing the nature of body is not at all evident and that Avicenna’s philosophy is in at least this way relevant for Western philosophy and philosophy in general.

              Physics (i.e. natural philosophy) in the Islamic world was generally closely linked with (Aristotelian) metaphysics and is signified as such in Avicenna’s thinking. (Duart 2003, 104-106, 109-110) Since physics was mostly a science concerned with natural bodies and motion, it was closely linked to discussions concerning causality. Avicenna therefore finds a proper place to discuss the nature of bodies in his Metaphysics of Healing in the broader context of discussing (necessary) existents, quiddity of bodies and causality. The discussion on the nature of bodies, corporeality and form and matter is grounded in both the Aristotelian and Neo-Platonic traditions in the frameworks of which Avicenna was working. (Lizzini 2017)

Three-dimensionality of body

For Avicenna, a determinate body must be three-dimensional. That is, a natural body must have length, width and depth. (Met. 2.2.2) Although length might be understood as a line, it is not necessary for a body to possess it, such as a sphere. Only if it would be in motion, a line would appear in the sphere, as a necessary or accidental concomitant of corporeality. (Met. 2.2.3) Moreover, Avicenna continues, ‘inequality’ of the three dimensions, or differences in measure of the dimensions realized in a body are possible without dissolving a postulated three-dimensionality in it. (Met. 2.2.4, 2.2.5.) Although it is possible to separate dimensions from body conceptually, it is impossible to do so in actuality: three-dimensionality in actuality is inseparable from its dimensions, and three-dimensionality is not separable from natural bodies, although the measure of the dimensions (that is the [interdependent] variety in length, width and depth) are variable: position, measure and limits of three-dimensionality are not part of the quiddity of body. (Met. 2.2.5.-2.2.7.) Avicenna then continues to illustrate this point by stating that wax might change shape, thereby changing the ‘measures’ and ‘limits’ of the body, but in doing so, does not lose its three-dimensionality. (Met. 2.2.8.) Even though it might asked whether this particular example gives us an insight into the essence of a particular body such as wax, such a question evidently passes by the purpose of the example. (2)

Divisibility of body

It here then becomes clear that bodies are divisible, since the measure of dimensions of a body are variable: a division of two bodies means separating that measured variability of dimensions in a set of two bodies. Three-dimensionality is preserved in this newly formed division since both newly shaped bodies will have three-dimensionality. Again, the measures of the dimensions vary and are as such not essential to the essence of body. Corporeality then is ‘not unreceptive of division’ (Met. 2.2.17) ; it is part of its nature. A version of atomism holds that atoms (being indivisible) are not composed of parts and are therefore not truly bodies since bodies are per definition composed of parts (Marmura 2005, 108) ; they might be regarded as ‘points’. Although Avicenna’s criticism of atomism doesn’t become sufficiently clear in the second Chapter of his Metaphysics, it is dealt with elsewhere. (3) However, we can shortly look into the matter of a further separation of atoms in actuality by an external cause. (Met. 2.2.16.) According to Avicenna, if an atom is indivisible, but is separate from another in substance, then that separation might not be the cause of the quiddity of the atom. The separation is a differentia of the atom, that which differentiates that particular body as a species from another form of species, caused by something external to the atom. (Met. 2.2.17.) Hence, if something outside of indivisibility is part of its essence, it necessarily contradicts with its indivisible nature (because its essence can be broken up into its parts). This is why atoms are necessarily fundamentally contradictory.

Matter as potentiality and form as actuality of body

This might not seem like a fundamental rejection of atomism (4), but it opens up the discussion of the place of matter and form in corporeal nature, since that by which the differentiation of a body is realized is caused by something external to the essence of a particular body (or atom), its cause might be found in the realm of general potentiality. Following the Aristotelian tradition of act and potency, it is stated that body is a substance composed of form in actuality and of matter in potentiality. (Met. 2.2.20). Matter in potentiality, that is matter-in-itself is devoid. Matter as a substantiality is ‘prepared’ to become actualized through form. (Met. 2.2.21) As a substance it might be differentiated through form, for which it is necessarily receptive. On the other hand, the so-called ‘form of corporeality’, is in need of matter and is able to actualize it. (Met. 2.2.23, 2.2.26) To illustrate this difficult point we could point at an actualized body – a thing in the world, such as a white piece of paper. It is not the case that the matter of ‘whiteness’ can be pointed at, whatever the myriad of actualized materials it is through which whiteness is manifested, whiteness in itself has no place in actuality. It is something that exists in potentiality and can only be realized through some form of corporeality. The essence of the form of corporeality is ‘simple, realized, with no variance in it’. (Met. 2.2.29) This means that any ‘species’ of form of corporeality is only possible materially, since it is essential to the form of corporeality itself that it necessitates materiality for its existence in actuality.

Conclusion

To conclude, the account of bodies as set out in chapter 2.2. of Avicenna’s Metaphysics of Healing makes three main points. Firstly, natural bodies are three-dimensional (i.e. have length, width and depth), but the measures of the dimensions are variable. Secondly, natural bodies are divisible. Their presumed indivisibility is a differentia that makes a body differ in species from another body; it is not its essence. Thirdly, bodies are in potentiality composed of matter and in actuality composed of form. From these points, it follows that causality as a subject emerges from the interrelationship between matter and form. The examination of the nature of body, therefore, takes a rightful and logical place within the framework of the discussion on metaphysics, the disquisition of which will be the subject of treatment following the chapter here discussed.

Footnotes

1) I would like to note that this topic is too exhaustive with regard to the entirety of Avicenna’s work, so this paper will mostly focus on the things stated and referred to in his Metaphysics of Healing 2.2 and will therefore not pretend to be able to cover all problems put forward by Avicenna extensively. For example, an extensive treatment of atomism is not possible, so it will only be touched upon in the context of the divisibility of bodies.

2) It might be beyond the scope of this paper to make a comparison with the ‘wax-argument’ of Descartes and it might even be insipid to make the comparison at all, but I would like to take the opportunity here to discuss the matter briefly, because I think it has interesting potential: the example of using wax to illustrate a point about bodies is both present in Avicenna and in Descartes, although Avicenna uses it to prove a general point about corporeality, and Descartes uses it to exemplify his doubt-experiment. Although both arrive at a point in which they seemingly grasp the essence of the object, the difference being that for Avicenna this is in regard to body qua body and for Descartes in regard to body qua wax (i.e. the essence of wax). A great difference would be that the ‘essence’ of wax for Avicenna would be more in line with Aristotelian thought, and therefore be regarded as a species of objects, while for Descartes then, it only makes sense to say something about the essence by turning to ratio itself. Of course, this comparison could go further on by contrasting the notion of three-dimensionality of bodies as quiddity of bodies with extension being the prime substance of objects, but that would require a paper in its own right.

3) E.g. Avicenna (trans. McGinnis, J.) 2010. The Physics Of The Healing. 1st ed. Brigham: Brigham Young University; 3.3 (general and mathematical arguments) or Avicenna (trans. McGinnis, J.) 2010. The Physics Of The Healing. 1st ed. Brigham: Brigham Young University 3.9 (a complex geometrical argument); for a further oversight for the types of atomism that are criticized by Avicenna, see: Marmura, Michael E. 2005. Probing In Islamic Philosophy. 1st ed. Binghamton: Global Acad. Publ., Binghamton Univ., 106-114 and related sources.

4) I’m personally not convinced by the strength of the argument (if I at least have understood it correctly), because in the view of an atomist, nature is composed of atoms and void: there is no notion of ‘species’ of atoms, only in the sense of infinite variety. But perhaps we can put it this way to maintain Avicenna’s point: couldn’t it be the essence of variety that atoms fundamentally differ from each other, rather than atoms being differentiated from each other because of some external cause, if variety is essential to the fundamental composites of bodies? If that’s the case, variable particularity might still coincide with indivisibility as a necessary essence of an atom, as something that essentially differentiates one atom from the other. This might not satisfy Avicenna’s thinking since he mainly argues against the existence of atoms, but it becomes clear that the variety of a particular atom needs to be caused by something outside it and it that matter is still divisible

List of References

Avicenna (trans. Marmura, M.E.) 2005. The Metaphysics Of The Healing. 1st ed. Provo, UT: Brigham Young University Press.

Avicenna (trans. McGinnis, J.) 2010. The Physics Of The Healing. 1st ed. Brigham: Brigham Young University.

Druart, T.A. “Philosophy in Islam,” in The Cambridge Companion To Medieval Philosophy, edited by A.S. McGrade, 97-120. Cambridge: Cambridge University Press, 2003.

Lizzini, Olga. 2017. "Ibn Sina's Metaphysics". Plato.Stanford.Edu. https://plato.stanford.edu/entries/ibn-sina-metaphysics/.

Marmura, Michael E. 2005. Probing In Islamic Philosophy. 1st ed. Binghamton: Global Acad. Publ., Binghamton Univ.