Life after life: Mullā Ṣadrā on death and immortality

Abstract The purpose of this article is twofold: first, I will reconstruct Mullā Ṣadrā's complex arguments for the soul's immortality based on its immaterial nature. Second and finally, I will briefly probe and assess various epistemological and metaphysical objections against Ṣadrā's immaterialist conception of the soul. Ṣadrā contends that our bodily death marks an awakening to the reality of our consciousness on the plane of the imaginal realm (the imaginal world is an isthmus between the sensible world and the world of intelligible forms). For Ṣadrā, ‘death’ does not mark an end or discontinuity in human consciousness, rather it signifies an awakening to a new mode of existence in which the soul, having once been the active principle controlling the actions of the physical body, now manifests itself as the passive recipient of the form given to it by its imaginal reality – a reality shaped by the actions it had performed in its earthly, embodied state. Thus, death is seen as the passage of the soul from the sensible to the imaginal world, until the soul unites with the intelligible world (ʿālam al-ʿaql).


Introduction
Does the 'soul' survive its 'death'? The answer to this question depends on how one explains the nature of the soul or the self and how one describes the phenomenon of death. 1 Since the time of Leucippus and Democritus, there have been those who elaborated a materialistic account of the natural world. Yet for all its worth, materialism never occupied a dominant position in the history of philosophy as compared to antimaterialist systems of thought such as Platonism or Aristotelianism, until perhaps recently when it emerged as a dominant paradigm in both science and philosophy. Consider, for instance, the argument of the physicist Sean Carroll (2011), who claims that the laws of physics that underlie all physical objects leave no room to account for something immaterial and non-physical like the soul. In his rendering, the immaterial soul must be something like a blob of spirit energy that sits near the brain and drives around the body like a soccer mom driving an SUV. Such an account of the soul, Carroll contends, must explain what form its spirit energy takes, and how it interacts with ordinary matter. For Carroll, one would require a completely new physics to account for the spirit particles of the soul, since within QFT (quantum filed theory), there cannot be a new collection of 'spirit particles' and 'spirit forces' that interact with ordinary matter. 2 If there were such 'spirit' particles, physicists would have detected them in their experiments. Moreover, one would have to explain how such 'spirit' particles respect gauge invariance and Lorentz invariance, or whether they have a Hamiltonian.
It is interesting to note that even though Carroll uses the term 'immaterial' in relation to the soul, he assumes that if the soul exists it must consist of particles that ultimately are of physical naturequantitative and measurable. One can perhaps excuse physicists like Sean Carroll for committing such a basic petitio principii, but his argument does flesh out one important aspect of the debate concerning death and immortality, namely whether or not the soul is immaterial. In the remainder of the article, I will explore and reconstruct the seventeenth-century Persian philosopher Mullā Ṣadrā's (d. 1640) complex arguments for the soul's immortality. For Ṣadrā, the soul's immortality is contingent upon its immaterial nature. While doing so, I also will probe and assess various epistemological and metaphysical objections against Ṣadrā's immaterialist conception of the soul.
The nature of the soul/self: material or immaterial?
Although Mullā Ṣadrā accepts the standard Aristotelian definition of the nafs (soul/self) as the 'first perfection of an organic natural body that has life potentially', he criticizes the peripatetic philosophers for falling short of understanding the self's true nature beyond its functional activities such as nutrition, locomotion, and perception that correspond to nutritive, sensitive, and rational souls respectively (Aristotle (1984), De Anima, 412b5); Metaphysics, 1017b, 1035b). But in Ṣadrā's view, such philosophers are not the only ones who fail to appreciate the self's true reality. He also launches a scathing attack on the masses (i.e. non-philosophical people), who are unable to conceive the self's transcendence beyond its sensible structure (al-bunya al-maḥsūsa). Needless to say, Ṣadrā's criticism would apply to physicists like Carroll as discussed above. Ṣadrā says: The majority of Muslims are of the opinion and believe that a human being is nothing but this sensible structure (al-bunya al-maḥsūsa), I mean the body composed of flesh, blood, bones, blood-vessels and what resembles them from the material bodies, and what inheres in them from accidents and qualities, activity and passivity (al-aʿrāḍ wa-l-kayfiyyāt al-fiʿliyya wa-l-infiʿāliyyā) in a particular mode which is the human form . . . (Mullā Ṣadrā (2001(Mullā Ṣadrā ( -2005 Ṣadrā complains that most of his contemporaries are heedless of the self's true reality, its mode of higher and lower levels, its waystations and its places of ascension, and the fact that its origin is from God and its setting and return is towards Him (ibid.,9: 251). In his view, one who ignores the self and does not know the reality of its essence remains the most ignorant concerning the knowledge of one's Creator, while one who comes to know the reality of the self, alongside its inner reality, the mode of its attachment to the body (ḥaqīqat al-nafs wa-māhiyyatahā wa-inniyyatahā wa-kayfiyyat taʿalluqahā bi-l-badan), gradual ascent, intensification in its being (ishtidād wujūdahā), resurrection to the next level, return to the actual intellect (rujūʿahā ilā al-ʿaql bi-l-fiʿl), and finally, its journey to God, attains the status of the divine knower (al-ʿārif al-rabbānī) (ibid.). Such an individual, owing to the experience of their inner illumination, realizes that the soul/self begins its journey as a corporeal entity, and then through substantial motion (al-ḥaraka al-jawhariyya) becomes a person, then an intellect, and then a divine ray that attains transcendence by its immersion in the ocean of God's exclusive unity (al-aḥādiyya) (ibid.).
Ṣadrā also takes religious scholars, especially the jurists ( fuqahā), to task for paying insufficient attention to the matters of the self. He expresses his dismay at people who claim to have knowledge of religion and yet remain satisfied at the level of the masses, and do not occupy themselves with the purpose of knowing the reality of their self. He laments that legal scholars spend all their time on secondary matters of jurisprudence ( fiqh) such as marriage and divorce, inheritance, political succession, etc., whereas they take the self's return (maʿād) to its origin (mabdaʾ) for granted, without knowing what such a return in terms of the self's movement entails (Mullā Ṣadrā (2002a), 2: 714-715). 3 Moreover, Ṣadrā believes that merely having faith in the Resurrection or carrying out ordinary religious injunctions would not be enough, since a real resurrection will not take place until one realizes that there are subtle bodies (ajsām laṭīf) other than the physical body, and that the physical body must be integrated into the former as the self (nafs) continues its ascent toward its origin (ibid., 2: 715). Thus, Ṣadrā's metaphysical eschatology goes further than the normative, Islamic belief concerning death and resurrection, even though he accepts it as a starting point.
According to Ṣadrā, the reason why most of these people have failed to realize the true identity of their self is that they have mistaken their physical body for the 'I', which represents their true self. This misidentification occurs because of the unified species (nawʿ waḥdānī) that comes about when the body and the nafs form a natural bond, thereby giving rise to a true compound: It is because of the natural bond (ʿalāqa ṭabīʿiyya) that exists between the nafs and the body that a unified species (nawʿ waḥdānī) results from their union, which then gives rise to a definition of the true compound as the genus ( jins) is derived from the body and the differentia ( faṣl) from the nafs . . . And it is because of that very bond of union that the nafs points to the body by the referent 'I', (anā), just as it points to its own reality by the same 'I', even though most people have forgotten their self (dhātahā) and imagined that their identity (huwiyya) lies with the body (wa-ẓannū anna huwiyyatahum hiya l-badan). (ibid., 2: 465) So much for Ṣadrā's criticism of philosophers' and the multitude's failure to grasp the self's complexity and immateriality. Let me now turn to the various arguments which he deploys throughout his corpus, including but not limited to the Asfār, 4 Mafātīḥ, 5 al-Mabdaʾ wa-l-maʿād, 7 to prove that the self is 'immaterial'. As noted earlier, if Ṣadrā can prove that the soul is immaterial, he can then show that its career does not end with a physical death.
At any rate, the most frequently used word for 'immateriality' in Islamic philosophy is tajrīd or tajarrud, which literally means disembodiment or disengagement, but in reality, it refers to the self's immateriality. 8 In the Asfār, Ṣadrā explains tajrīd as the self's transcending matter and material conditions (anna al-nafs al-insāniyya mujarrada ʿan al-mādda wa-lawāḥiqihā)) (Mullā Ṣadrā (2001-2005), 8: 356). 9 The concept has a long pedigree in the history of Islamic philosophy, and Ṣadrā pays close attention to his predecessors while discussing it. 10 After perusing all the relevant texts, it seems to me that Ṣadrā's most decisive argument concerning the issue can be found in his al-Mabdaʾ wa-l-maʿād, in which he also responds to all possible objections in the form a dialogue (cf. ibid., 8: 320ff.). 11 In order to give the reader a more authentic flavour of how Ṣadrā presents his case, I will quote him at length before teasing out all the salient features of the argument. The following dialogue offers Ṣadrā's argument concerning the self's immateriality: I say (i.e. Ṣadrā): We perceive our self (dhawātanā), and everyone who intellectually grasps (kullu man ʿaqala dhātan) himself, grasps his own quiddity (māhiyya). Therefore, we grasp our own quiddity. However, we grasp our self either through another form which is equivalent to our self or through our own self. The first option is absurd because it implies conjoining of two similar entities (al-jamʿ bayn al-mithlayn), hence the second option is affirmed. And whatever grasps itself through itself is self-subsistent. So, the intellectual faculty must be self-subsistent, because everything that is either a body or bodily cannot be self-subsistent, which proves that our intellectual faculty must be non-physical (lā-jismānī). (Mullā Ṣadrā (2002a), 2: 478;cf. Mullā Ṣadrā (2001cf. Mullā Ṣadrā ( -2005 The Questioner: There is no certainty that we perceive ourselves through intellection (annā naʿqul dhawātanā); why cannot we say that our perception of ourselves refers to a mode that is different from intellection? This is because intellection is defined as the coming to obtain of the quiddity intellected for the one who intellects (ḥuṣūl māhiyyat al-maʿqūl li-l-ʿāqil). It is not possible that we know ourselves as the agent of intellection except when we can already affirm self-perception for the self. Then it would be possible to explain the reality of our self without having recourse to intellection (dūn wasāṭat al-taʿaqqul). So why should it be said that we perceive ourselves and that our reality of our self (ḥaqīqat dhawātinā) is affirmed by means of it (intellection)? If it were not thus, it would not be possible to explain how we are able to intellect anything at all except by explaining the self's grasping of itself, and it is not possible to explain it except by means of the self's intellection, and this leads to circularity. (Mullā Ṣadrā (2002a), 2: 478-479;cf. Mullā Ṣadrā (2001cf. Mullā Ṣadrā ( -2005 I say: It is enough to state the mode of unconditioned perception (muṭlaq al-idrāk) as our proof. Our argument is not directly related to intellection or consciousness (taʿaqqulan aw shuʿūran) because it has already been shown that perception is grasping the object's quiddity by the perceiver. (Mullā Ṣadrā (2002a), 2: 479) The Questioner: Granted. We do perceive ourselves, but this does not prove that whoever perceives himself grasps the quiddity of his self. For instance, even though we perceive heavenly bodies and the intellects (al-samawāt wa-l-ʿuqūl), their realities remain unknown to us. (ibid., 2: 480) I say: We only grasp the quiddities and species (māhiyyātahā wa-nawʿiyyātahā) of things that are external to us. However, we do not grasp them insofar as they are individuals. Moreover, their modes of being (anḥāʾ wa-wujūdātuhā) are different from each other, even though they are grasped with respect to their accidents. However, the reality of [our self] as the object of intellection is grasped in respect of its identity, which is not different as far as its species, quiddity, accident, or personhood (shakhṣiyya) are concerned. Our intelligible form is our very individuality but when it comes to the Active Intellect, the intelligible form is a single species, and does not consist of personhood. (ibid.) The Questioner: That much is granted, but why is it now allowed to say that I do not perceive myself through the estimative faculty, just as the intellective faculty perceives by means of the former (kamā anna l-quwwa al-ʿāqila yashʿuru bi-l-wahmiyya)? (ibid., 2: 481) I say: Your awareness of your identity (shuʿūrika bi-huwiyyatika) is not mediated by your faculties, or else, that by which one becomes conscious would not be the same as consciousness itself. The consequent is false, so is the antecedent. As for the explanation of mutual implication: whatever possesses self-consciousness grasps itself through itself (ḥaṣil li-dhātihi). If the faculty by which you perceive yourself subsists by yourself then your self is affirmed, which is the desired conclusion, but if it subsists by your body, then your self too either subsists by your body or it does not. If it does not subsist by the body then you should have no awareness of your self, [which is false] (ibid.). 12 If it does so on the contrary then both your faculty and your self are grasped by the body . . . but they are not conscious of each other, rather both of their quiddities are grasped by the body . . . one should also remember the rule that states that the grasping of an entity for another entity is contingent upon the former's grasping of itself . . .
The Questioner: why is my self-perception (idrākī li-dhātī) not like something where I perceive myself in a medium just like I see myself in a mirror? (ibid.) I say: It is evident that that which is seen by means of a mirror has an impression in the mirror, which is then reflected in the pupil. Likewise, that which is represented as our form must be reflected a second time in the mirror of our self . . . but it is not possible to have the medium of mirror as 'perception of the self' for the self. (ibid., 2: 482) The Questioner: Why cannot I say that self-perception occurs through another form? Its explanation: When I perceive the self of Zayd, I also perceive myself because whenever someone intellects something and brings it to actuality from the proximate faculty (al-quwwa al-qarība), it becomes aware of itself at the same time. So that which is grasped at that moment in my self about my self ( fī nafsī min nafsī) and Zayd must be either two forms or one form. The second is rejected, or else it leads to having a form of both me and the other person at the same time. The first holds since my perception of myself comes about through a form of me in me (min dhātī li-dhātī). (ibid.) I say: When you perceive yourself unconditionally (idhā ʿaqalta al-nafs muṭlaqan), you perceive your parts as well. Whatever you perceive in addition to it, for example, Zayd, does not repeat itself. . . However, with the unconditioned perception, the self does not itself become a part . . . (ibid.;cf. Mullā Ṣadrā (2001cf. Mullā Ṣadrā ( -2005 The Questioner: Our saying 'existent by essence' has two meanings: (1) in its Essence It is not attached to anything else, (2) it does not inhere in another like that of form in matter or accident in substance; this is also rejected . . . (Mullā Ṣadrā (2002a), 2: 483) I say: The essence of a thing is something different from its conceptual determination (mafhūm taʿayyunihā) . . . for example, the Necessary Being . . . my self and your self . . . your self can be added to your self . . . But this implies no dualism. (ibid.) The Questioner: Even though animals do not have an immaterial self, they perceive themselves. They look for comfort and flee from the harmful . . . This shows that they have awareness. (ibid.) I say: Only the human self perceives itself through itself (nafs al-insān tudriku bi-dhātihā dhātahā). Animals (al-bahāʾim) perceive themselves by means of the estimative faculty (bi-awhāmihā dhawātahā) and their selves are represented by the instrument of this faculty. (ibid., 2: 484) The Questioner: What is the proof that our perception of ourselves is not like that of animals? (ibid.) I say: We possess a self-reflexive faculty. Our self-awareness allows us to disengage various individuating accidents (al-ʿawāriḍ al-shakhṣiyya) it perceives through its own awareness . . . Animals do not have self-reflexivity. Also, animals cannot disengage themselves from their body . . . Their awareness is limited to estimation (wahm) . . . They do not have self-awareness, since they lack an intellective faculty. (ibid.) Also, the human self is always aware of itself (mashʿūr bihā fī jamīʿ al-awqāt), even in a state of sleep, intoxication, and fainting, and it is not one of the parts of the body such as the heart, brain, and vaporous spirit (rūḥ bukhārī), even though it may be forgetful sometimes. Most people hardly perceive all of their bodily organs, or even when they do, they do so through dissection or by some other means. However, their awareness of themselves remains continuous. That whose awareness is continuous cannot remain unaware of itself for some specified time. But consciousness of the body, or parts of it, or some of its accidents that subsist on it, or on some of its parts, is never continuous in itself. So that by which things are made conscious must be other than the body, or its states, or another body with its given states. All of this is plain. (ibid., 2: 485-486) The broad contour of this argument, which I call 'argument from self-knowledge and selfconsciousness', begins from the premise that 'everything that intellects itself, grasps its own quiddity'. This is because a thing which is capable of self-intellection, by definition, suggests that it is able to know its 'whatness', which distinguishes it from everything else. Then he proceeds to assert that since we intellect our self, we must be able to grasp our own quiddity (māhiyya). However, if we intellect ourselves through a quiddity, it still implies that we are adding another form to our 'self'. This means we do not really intellect ourselves as ourselves, since our 'quiddity' as a concept comes in between. In other words, the self can think of the quiddity of the human, i.e. humanness, to identify itself, or other universals such as substance, person, or even the very concept of 'I' (which is a universal as a concept) to refer to itself, but in such cases it would be mediated 'universal knowledge', and as such, would fail to refer because each 'I' experiences itself as a concrete and particular 'I'. Hence, even the concept of 'I' would be an 'it' in relation the particular 'I', or the owner of a given subjectivity.
The only way to get around this quandary would be to assert that we are already acquainted with our self in an a priori, non-objectifying fashion, which is existentially identical with the very being of the reality of ourselves. In other words, we know ourselves directly through our consciousness, which is the very nature of the self because the essence of our selfhood at its most basic level is this very consciousness. From this Ṣadrā further deduces that whatever grasps its self through itself must be self-subsistent, since anything which is bodily cannot be self-subsistent. 13 That is, the body in itself lacks self-consciousness and thinking. The opponent objects by saying that even though we are capable of self-intellection, this does not mean we perceive our inner reality, since we perceive heavenly bodies or the Active intellect or even God, but their realities (i.e. their quiddities) remain hidden from us. Ṣadrā responds by saying that we only perceive the specific (nawʿiyya) nature of the heavenly intellects because the species of every one of the immaterial intellects is restricted to its individual instance. This means they are different from common entities around us. On the contrary, the reality of our self as the object of intellection is grasped in respect of its identity, which is not different as far as its species, quiddity, accident, or personhood are concerned. As for God, He does not have a quiddity, so His Essence remains unknown to us. 14 Then the opponent raises an objection concerning 'animal awareness' by arguing that animals also perceive themselves. In response, Ṣadrā retorts that animals perceive themselves through their faculty of 'estimation' (wahm), and that they do not have the capacity to carry out intellection. 15 Hence they only possess some limited form of awareness. Humans, on the contrary, have self-reflexivity, continuous awareness of themselves. And that whose awareness is continuous cannot remain unaware of itself for some time. But the body or any of its parts do not have continuous awareness. So that by which things are made conscious must be other than the body, or its states, or another body with its given states, which is to say that the self must be other than the body or immaterial. In addition, Ṣadrā also deploys ten other arguments to demonstrate the self's immateriality, as outlined below (Mullā Ṣadrā (2001(Mullā Ṣadrā ( -2005 (iv) Argument from 'self-perception without involving the organs of body'.
(v) Argument from 'the strengthening of intellectual capacity despite weakening of material faculties with age'. (vi) Argument from 'the perfection of the intellect in contrast to the other faculties'. (vii) Argument from 'the independence of the self in its acts'. (viii) Argument from 'the unity of perception'.
A full elaboration of all of these arguments is beyond the scope of the present focus, but I will nevertheless analyse another argument, namely the 'argument from the unity of consciousness'. Ṣadrā says that if we assume the body as such to be the perceiver of things, then it follows that all parts of the body somehow partake in perception, which is absurd. Likewise, if we assume that there is a bodily faculty of perception that either exists in all parts of the body or in some of its organs, the following absurdities follow. First, if this faculty exists in all parts of the body, every part of the body would then be seeing, hearing, imagining, thinking, and so on, which clearly is not the case. For the sight cannot hear, the hand cannot imagine, or the leg cannot think. It is also absurd to claim that there is a faculty of perception that exists in some of the organs of the body. Because this would imply that there is an organ in the body, which is the hearer, the seer, the subject of imagination, the thinker, the intellect, but at the same time we do not know which one it is and where it is located. This argument also brings out the absurdity of the claim that the faculty of perception for all these perceptions subsists in the subtle body ( jism laṭīf), which is encompassed by some organs (ibid., 8: 353-354). However, one might respond by saying that just because we do not know its location, it does not mean it is non-existent. Ṣadrā replies by having recourse to a priori self-knowledge. He explains that we know that we hear, see, imagine, and think. So, if something from the body, be it a part of the body or something within a part of the body, is the perceiver of all the perceptibles, then our reality would only be that part of the body described by that faculty which has the attribute of these perceptions. If that were the case, and we are yet not aware of it, then we could not be the knowers of the reality of our self (ibid., 8: 354). Since this is a reductio ad absurdum argument, the premise must be rejected. Therefore, our self must be an immaterial entity which is able to perceive without giving up its unity.

Materialist objections
The above arguments counter both behaviourism and functionalismtwo of the dominant accounts of the materialist theory of the mind (Armstrong (1993) and Lund (2009)). For instance, in the functionalist theory of the mind, a mental state is defined by its functional or causal role in the overall activity of the individual as they receive sensory information from an external source, process that information by way of the neurochemical activities of the brain, and then respond through a visible behaviour. Thus, for a functionalist, a mental state such as pain simply fills the causal role of mediating between the stimuli received because of bodily injury and the pain behaviour that is outwardly manifested. From a Ṣadrian point of view, such an account already presupposes an a priori, background awareness on the part of the subject experiencing pain. More specifically, since this awareness is continuous and unobjectifiable, it is presupposed by all brain activities which are, by definition, particular. That is, since all brain states that account for pain consist of particular neuro-chemical activities, we need to presuppose something else that can account for our continuous and unobjectifiable awareness. For Ṣadrā, the underlying subject of this awareness is the immaterial self.
Beyond functionalism, philosophers worry about the conceivability of a disembodied, immaterial self once the soul dies. They wonder how such an immaterial self can be located in space without any bodily basis, coupled with the problem that we will be unable to ascertain if a disembodied person is numerically identical to its former self. That is to say, even if we are able conceive of an immaterial self in its embodied state, we would be unable to tell, once we die, if the person we are remembering is genuinely myself or someone else (McGinn (1999), 27). Added to the ontological and epistemological problem of conceiving an immaterial self is the issue of 'dependency on the brain' argument, which further complicates the post-mortem existence of an immaterial being.
It is hard to deny the causal connection between the brain and various conscious activities. This is most noticeable when the normal functioning of consciousness ceases with biological death or when there is a major mental disturbance due to malfunctioning of portions of the brain. Moreover, modern neuroscience has uncovered how various drugs influence mental states by altering brain activity. The effects of such powerful psychotropic drugs as cocaine, opium, lysergic acid, psilocybin, and mescaline on consciousness are well known (Lund (2009), 24-28). Moreover, artificial electro-stimulation of the brain provides a striking example of how conscious states can be caused to arise simply by generating tiny electric currents in certain regions of the brain, thereby showing how changes in the brain bring about corresponding changes in consciousness. For the materialist, all of these observations and evidence decisively refute the idea that one may survive one's death through an immaterial self. 16 Beyond the physical: body and death in the Ṣ adrian perspective While these arguments may sound very convincing to a modern audience, especially in light of the mammoth body of neuroscientific evidence concerning the mind-brain relationship, they will nonetheless seem incomplete from a Ṣadrian standpoint. To begin with, Ṣadrā will take issue with the assumptions of a purely materialistic understanding of the body, soul, and death. As alluded to earlier, Ṣadrā contends that our bodily deaths mark an awakening to the reality of our consciousness on the plane of the imaginal realm (the imaginal world is an isthmus between the sensible world and the world of intelligible forms). For Ṣadrā, the physical body is only the first stage in the soul's development through which it moves into the imaginal phase after 'death'. Equipped with the notions of the imagination, the imaginal world, and the imaginal body, Ṣadrā argues that the 'substantial motion' (al-ḥaraka al-jawhariyya) of the soul after death is not simply biological, as is the case when it resides 'in' a physical body. Rather, the post-mortem stage of the self's development takes shape in a subtle, imaginal body weaved through the imaginalized representations of our actions performed on earth. 17 This means the events which take place during the self's posthumous state occur within itself. The more the soul becomes perfect in its existence (according to Ṣadrā's doctrines of the 'primacy and gradation of being' and 'substantial motion'), the more the body becomes limpid and subtle, and its attachment to the soul becomes stronger and more intense. Thus, death is seen as the passage of the soul from the sensible to the imaginal world, until the soul unites with the intelligible world (ʿālam al-ʿaql). 18 In other words, the issues of ontological and epistemological discontinuity between an embodied and disembodied self (i.e. location and identification) do not arise, since even after death the self inherits a 'body', albeit a body of an entirely different kind. Anticipating queries concerning the dimension and mode of operation of such a body, Ṣadrā asserts that it is meaningless to ask whether we are on the inside or the outside of our cosmos, or whether we are above the Sphere of Spheres that determines the coordinates of sensory space or whether we are included in the circles of the Heavens, or whether we are below the celestial Spheres, since here we are concerned with another realm of existence, whose geometry is radically different from the material world (Corbin (1977), 166). 19 Ṣadrā also suggests that bodies and volumes are unbounded in the other world, because they originate from the imaginations and perceptions of souls, which are marked by endless variations. The fact that in our world dimensions are necessarily finite does not apply to the imaginal world. Yet, there is neither crowding nor discomfort in that world, as no body is outside another, nor inside it (think of dreams where 'space' is not experienced). Every human being possesses a complete universe, vaster in itself than our world, and never forming and generating, in relation to another person's universe, as it were, a step in the same series, because each soul possesses whatever proportion of the entire series it desires (ibid., 167).
More importantly, 'death' in this perspective does not mark an end or discontinuity in human consciousness, rather it signifies an awakening to a new mode of existence in which the soul, having once been the active principle controlling the actions of the physical body, now manifests itself as the passive recipient of the configuration given to it by its imaginal realitya reality shaped by the actions it had performed while being in an earthly, embodied state. Ṣadrā uses the language of hylomorphism to explain this notable transformation of the soul after death. That is to say, in its earthly mode of existence, the soul functions as the form of the material realities of our world, while in its post-mortem state, it serves as the matter of the forms of the world beyond, namely, the spiritual realm. 20 Thus, the soul is the meeting place or barzakh between the physical and spiritual poles of existence, or between light and darkness, life and death, awareness and unconsciousness. Each of us is a soul or an embodied spirit/intellect. The soul or self defines what we experience of ourselves. Our experience of our own and other bodies is mediated by the soul, and so also our experience of the spirit. The soul is both form or actuality in relation to the matter of the body, and subtle/imaginal 'matter' in relation to the spirit/ intellect. All this is to say that the essence of the soul as spirit/intellect remains 'immaterial' whether one considers its earthly or post-mortem career, but its bodily form changes as it transitions from one mode of being to another.
The movement of the self or human becoming is best understood through Ṣadrā's complex doctrine of substantial motion. Ṣadrā describes the self's movement from the moment its life begins as a foetus in the womb when the corporeal faculties that are attributed to the plants are generated. But the self possesses a 'form' that potentially contains all the perfection of animals, humans, and the intellects. So the human embryo, although it functions as a plant, is a potential animal. Next the human embryo attains the level of the animal self with all their cognitive powers, such as the capacity to cognize as animals until it reaches maturity of the human form when it actualizes the powers of the rational self. At this level, the self is capable of perceiving the world around it through its reflective faculties. The self's becoming continues until it reaches spiritual maturity, while developing 'the practical intellect' which facilitates internal growth by the strengthening of good habits and moral qualities. According to Ṣadrā, it is at this point that the self realizes its identity as an actual human self, while still being a potential angel or demon. Then if the intellect is perfected through knowledge and the heart purified through disembodiment, the self attains proximity to the divine. Ṣadrā also makes it plain that these later developments occur only in a small number of individuals, most likely when they awaken to the reality of the imaginal world after death (Mullā Ṣadrā (2001(Mullā Ṣadrā ( -2005. Ṣadrā offers a thorough critique of the people who, as he claims, surmise that the human self is only composed of a natural form (ṣūra ṭabīʿiyya) having three souls, namely vegetal, animal, and human. In his view, these people get it wrong when they observe in humans the traces of various natural principles, such as heat (ḥarāra) and cold (burūda), attraction ( jadhb) and repulsion (dafʿ), dissolution and ripening, etc., or other traces related to plants, such as nutrition, growth, and reproduction, or to animals, such as sensation, imagination, or traits such as rational perceptions and reflective movements that are specifically human, and assume that there is nothing beyond these psychosomatic functions (ibid., 8: 153-54). According to Ṣadrā, the human self is a sacred substance ( jawhar qudsī) that has a close affinity with the spiritual kingdom. Moreover, it has one identity (huwiyya wāḥida) comprising several modes of being (nashʾāt) and stations, and its unity, which is comprehensive, reflects divine unity (ibid., 8: 154). Although Ṣadrā talks about the self's becoming through 'substantial motion', it should not leave us the impression that every step in the self's journey is naturally determined. This is because, as Ṣadrā insists, even though the self is capable of passing through all the stages until it reaches its destination in God Himself, it acquires various habits, either noble or lowly, and opinions and beliefs, either true or false during its earthly life. Consequently, the post-mortem stage of the self is shaped by the actions it performs or the beliefs it harbours in this world (ibid., 9: 39).
Coming now to the 'dependency on the brain argument', Ṣadrā grants that ordinary perception requires the cooperation of physical organs such as the eye, ear, or the brain, in addition to receiving stimuli from an external source. However, what is perceived or experienced in the mind is never anything but an outer form imitating and exemplifying the form already present in the soul, whose innermost essence springs from the spiritual/intelligible world. For this reason, when the soul gets used to perceiving a given object, it is often able to contemplate the form of that object in its own realm without requiring an external object as intermediary. Ṣadrā duly acknowledges the crucial role of memory and the imagination in this process. But after death the soul develops psychic senses alongside an imaginal body, which allows it to feel and perceive without the intermediary of either the brain or sensory organs (Corbin (1977), 166). 21 This is analogous to how the soul perceives in a dreamworld, although the imaginal world presents a distinct, cosmological reality of its own.

Concluding reflections
Looking at the arguments from both sides, it becomes clear that they involve accepting different premises, hence different conclusions. Ṣadrā's perspective on death and immortality depends on embracing a cosmology which transcends the naturalistic assumptions of many contemporary philosophers. Many people today only accept proofs that result from mathematical modelling and physical evidence. For thinkers such as Alex Rosenberg (2020), such an attitude is a necessary concomitant of the so-called successes of modern science. Broadly, for such philosophers, the success factor of empirical science far outweighs the methods of philosophy or any other tradition that purport to illuminate the nature of reality. Therefore, only what is affirmed by science as real can be counted as real. Needless to say, this is a highly contentious claim, since what counts as 'scientific' or whether one can only mention 'success' in relation to science are both widely debated (not least because of the present environmental and nuclear crises). Moreover, while empirical science can boast of its ability to develop theories such as general relativity and quantum mechanics, it is much less clear whether it can deliver confident judgements when it comes to the nature of being (wujūd) or consciousness. This is a vast topic, but briefly, empirical sciences face a fundamental challenge when it comes to human subjectivity, since they cannot give us access to subjectivity from the outside. Any scientific thinking presupposes that we are already conscious of ourselves and others. So, when we use a scientific method to investigate a given aspect of subjectivity (i.e. a given mental state or conscious activity), we are always necessarily objectifying it by using and relying on our subjectivity. But consciousness is always a subject in relation to a known object, even though sometimes it can be represented in the mind as an object. Some would argue that empirical sciences cannot even provide a complete description of the natural world, since they operate on the basis of the famous Galilean distinction between primary and secondary qualities as well as the hypothesis that the book of nature is written in the language of mathematics. One can mention philosophers such as Husserl and Heidegger in this regard, who have brought into the open many of the fundamental epistemological and ontological assumptions clouding modern science (see Husserl (1970) and Heidegger (1977)).
Also, many contemporary philosophers will object to the fact that the soul can still make progress in its post-mortem stage when it is no longer associated with an individual who acts in the world. Mullā Ṣadrā will respond by saying that the sort of individuality which characterizes the self in this world will disappear once the soul enters the imaginal realm after 'death'. The soul will no longer have free will in the post-mortem stage of existence, as its movement will be determined by the subtle, imaginal body it inherits on the basis of its actions on earth.
Be that as it may, Ṣadrā's views presented here must not be confused with the quotidian, religious understanding of death and immortality, as the former involve wellarticulated philosophical premises. Nor should his talk of the subtle, imaginal body be conflated with popular literature on the astral body, out-of-body and near-death experiences, or parapsychology, for these phenomena involve varying and conflicting interpretations, whereas Ṣadrā presents his case using rigorous philosophical arguments. Above all, the nature of human subjectivity itself, with its complex features of reflexivity, intentionality, indivisibility, unity of consciousness, and thinking, alongside its capacity for moral and spiritual reasoning, presents an ever-stumbling block to the materialistic conceptions of the mind in relation to death.