A Persian wunderkind born in the tenth century AD, Avicenna (the Latinized version of the name ibn Sīnā) knew a thing or two about plants. In addition to his enviable expertise in mathematics and physics, philosophy and astronomy, geology and Islamic theology, Avicenna was a practicing physician and the author of a five-volume Qanun, The Canon of Medicine.
For centuries after its composition, The Canon continued to be revered as the gold standard of the medical profession in Europe and outside its confines. This medieval state-of-the-art manual dealt with plants as the components of a human diet and, numbering in the hundreds, as remedies for sundry ailments. So essential were they to the Avicennian medical system that the book’s English editors decided to preface the text with an excerpt from One Thousand and One Nights, where Scheherazade sings praises of the sage of Duban—the prototype of our sage—“conversant with the virtues of every plant, dried and fresh, the baneful and the useful.”1
Dietwise, and contrary to what we might expect, Avicenna did not consider the consumption of fruits to be beneficial for human health. “Fresh fruits,” he categorically stated, “are only good for those who carry out hard work, or take much exercise…for they render the blood too watery, and so it is apt to ferment.”2 Intense physical activity was recommended as an antidote meant to counterbalance their adverse effects by purging the blood of vegetal “crude humours” and lightening the burden these imposed on the human organism. Shockingly for us, about one thousand years prior to the “Five-a-Day” program implemented by the U.S. Department of Agriculture (USDA), fruits were seen as much more detrimental to human well-being than meat and wine.
The curative property of plants was another focal point of The Canon and, at the same time, a point of convergence for Avicenna’s theoretical knowledge and some of the ill-fated events in his biography. Take, for instance, celery. The philosopher-physician deemed this plant suitable for improving digestion and liberally prescribed its seeds as a diuretic remedy.3 When he, too, experienced the very digestive symptoms he had described, Avicenna did not hesitate to self-medicate in what he believed to be the strictest adherence to his own manuscript’s guidelines. But things did not turn out the way he had expected.
Shortly before his death, Avicenna accompanied the prince of Isfahan on a military campaign. Seized by a colic attack and apprehensive that he would be left behind, he administered eight enemas to himself, causing intestinal lacerations.4 Thereafter, he ordered an injection of two danāqs of celery seeds—a dose that was exceeded at least tenfold when, ignoring explicit instructions, five dirhams of the extract were dispensed.5 To make matters worse, having determined that he should take opium for the alleviation of epileptic symptoms, Avicenna received an overdose of the drug from servants who used the occasion to rob their master.6 Amazingly, these incidents, sufficient to debilitate the average person, failed to slow him down. The sage continued to indulge in the dietary and sexual excesses, for which he was infamous, preferring to measure the days (and the nights) of his life in breadth, rather than in length.7
Evidently, Avicenna learned a great deal from Aristotle, save for the patently Aristotelian virtue of moderation, that is, of finding an optimal middle course between surfeits and deficiencies. If we are to trust his biographers (and the accuracy of their assertions is currently under dispute),8 the real cause of Avicenna’s death was vegetal excess: various overdoses of herbal medications, overeating, and, according to the disciple Al-Juzajani, extremely frequent sexual intercourse. Besides the actual celery and poppy seeds—the source of opium—directly implicated in the philosopher’s death, the two hyperactive dimensions of his vegetal soul—the nutritive and the reproductive—also had a hand in his demise.
When pressed about the pitfalls of such a hectic lifestyle, Avicenna responded: “God, Who is exalted, has been generous concerning my external and internal faculties, so I use every faculty as it should be used.”9 In reflecting on his life, he did not seem to give much thought to the inner conflict among the faculties, nor did he reckon that some of them had to be controlled by other, more rational regions of the psyche. Much different, as we shall discover, is Avicenna’s theoretical view of the soul, whose parts, organized in rigidly hierarchical and quasi-feudal relations, owe obedience or reign supreme depending on their respective positions in the psychic edifice.
The immoderations of the philosopher’s life, pointing in one way or another toward the vegetal sphere, parallel his view of plants as the placeholders of ontological excess. In their basic constitution, Avicennian plants are so chaotic and unstable that they are barely fit for receiving a soul. According to his cosmogony (a theory of the origination of the universe), the elements of earth, fire, water, and air must come together in more or less balanced proportions to furnish matter capable of receiving a form (which is another word for a soul). Plants have something of this harmonious mix: “When the elements are mixed together in a more harmonious way…other beings also come into existence out of them due to the powers of the heavenly bodies. The first of these are plants.”10 Closer to the state of equilibrium than minerals, plant matter is “disposed for receiving the vegetal soul.”11
Regardless of the thesis that plant matter is a definite advance on the crudeness of stones, it is the least balanced substratum of the living. The subaltern position of plants at the bottom of the metaphysical hierarchy stays unchanged throughout the philosophical tradition; what varies is the justification of their presumed inferiority. As Avicenna would have it, of all kinds of creatures, plants exhibit the greatest deviation from the mean. If an animal comes “after the plant,” it is because the former “emerges from a compound of elements whose organic nature is much nearer to the mean…and is therefore prepared to receive the animal soul, having passed through the stage of the vegetable soul.”12 On its progress from chaos and disharmony toward perfection, the soul must shed its vegetal shape, which Avicenna significantly calls “natural,” taby’yat.13
Animal and human forms are, in comparison to those of plants, denaturalized. So, does the association of the vegetal with the natural bestow upon this stratum of existence a modicum of normality we usually attribute to nature? Not at all. With reference to the measurements of pulse, Avicenna clarifies that the natural is, above all, that which is exceptionally strong and vigorous, “excessive as to strength.”14 Faithful to the Greeks in one respect, he parts company with them in another. As in ancient Greek philosophy, nature is still metonymically expressed in the plant, and it is for this reason that the faculties of the vegetal soul are designated as “natural.” But Avicenna’s nature is not exactly the total movement of self-generation and harmonious growth that it was for the ancients; it denotes excessive vigor in exercising a function or the disequilibrium of elements still lacking the cohesive force and form of the soul. The philosopher’s replica concerning the use of his faculties is, undoubtedly, tied to the first signification of the natural: nature as vigorous excess in him and in the plant…But such “cherry picking” is untenable, since the two definitions of nature (hence, of vegetation) go together. That is why the vigorous use of the philosopher’s reproductive and nutritive faculties led to his ruination.
The excesses integral to plants do not foil their search for perfection. Growth, for instance, strives toward perfection when it augments the bodily extension of growing beings in a balanced manner: “Growth implies an increase in all directions in the proper proportion. To become fat or obese with advancing years, after being slim, is not growth. It is not growth unless the increase is in all directions and in natural proportions, so as to culminate in a state of perfection of growth.”15 Yet the plants’ striving toward perfection is easily thwarted thanks to their exposure to externalities that obstruct their development and growth. The example Avicenna cites in The Metaphysics of The Healing is “the cold’s freezing of plants, afflicting them at the time ripe for their perfection, so that [their] proper preparedness and what is consequent on it become corrupted.”16 Provided that plant matter is inherently unbalanced, external disturbances have a greater impact upon it than upon the animals, who are better suited to resisting environmental contingencies. Avicenna does not know that plants, as a rule, do not resist but adapt to and work with the environment by changing their physiological and morphological states. For him, plants are defenseless. Too weak to overcome whatever hinders their striving toward perfection, they persist in the state of unrealized preparedness, breathing with the promise of form that is far from being actualized. But, then, so do human thought and existence!
The poverty of nature in Avicennian thought is astonishing. Although the philosopher tends to refer to the vegetal soul as the “natural faculty,” in his understanding, nature is still more deficient than the plant that exhibits the first and shakiest union of matter and psychic form. Taken in isolation, nature is impotent, “unable to originate a souled body in one stroke” and “in want of a power by which she can fabricate a living body by the promotion of growth.”17 To generate anything, nature requires the assistance of Divine Providence, which is the unquestioned source of the soul, from the simplest vegetal to the most complex human varieties. We might say that Avicenna anticipates the modern reductive view of nature as a conjunction of mathematizable and mechanically driven processes. To be sure, in contrast to modern naturalism, his mechanized nature is made tolerable by the deus ex machina of the soul. But, subtract this “soulful supplement” from his philosophy, and you will end up with a world uncannily resembling the Newtonian universe of efficient causes and effects.
So, what belongs within the realm of nature, properly so called? In addition to the classical elements, Avicenna includes under this heading four forces: “the attracting, the holding, the digesting, and the excreting (repelling) [jādhiba, māsika, hādima, dāfi’a].”18 Intimately related to the nourishing, growing, and reproductive faculties of plant soul, the four forces of nature are inferior to these self-organizing—in contemporary parlance, autopoietic—capacities. Their inferiority allows plant soul to establish its tenuous mastery over nature. Vegetal life is, as Avicenna has it, “sub-served” by the forces of nature.19
The relations of mastery and vassalage binding together the living plant and the inorganic world give us an accurate snapshot of the socioeconomic relations in the times of Avicenna. Whereas the plant may be a feudal lord over the elements, it is still reduced to the serf of the animal and the human. What is more, since its soul does not subsist as a simple unity, its different faculties enter into relations of mastery and subservience among themselves. The hierarchical (political) economy of plant soul is the cynosure of Avicenna’s “Aristotelianism with a twist.”
With recourse to elementary logical deduction, we conclude that when Avicenna defines vegetal soul as “natural” (taby’yat), he obliquely ascribes to it the deficiency of nature and an unstable form of life verging on death. The plant’s proximity to the mechanical forces of nature is especially evident in the nourishing part of its soul that strings together the attracting, the holding, the digesting, and the excreting. The nutritive faculty, ghāzīa, is “that whereby the aliments are transformed into the likeness of the thing nourished, thereby replacing the loss incidental to the process of life.”20 To transform the nourishing other (for the plant: sunlight, water, minerals, etc.) into the nourished same, this faculty must engage directly with the four forces of nature, adding to them the practical notions of difference and identity. Avicenna stresses that ghāzīa is not to be confused with the digestive power “in its service”21 precisely because the nutritive faculty is above and beyond mere digestion and introduces relations that are no longer only physical but crudely spiritual, that is, difference and identity. At the same time, this faculty is comprehended as the lowest stratum of the lowest kind of soul as a result of its near immersion in the realm of nature. Actively mastering the attracting, the holding, the digesting, and the excreting, the nutritive faculty passively submits to the “augmentative faculty” of growth, nāmīa.22 Why?
In A Compendium on the Soul, Avicenna distinguishes two types of movement: that according to the element and that against the element. The first type is completely natural, such as a heavy body that strives downward, toward its proper element, the earth. The second type is, for a lack of a better term, spiritual; it betrays the existence of a soul that drives the ensouled body away from its physical element, as does “a flying bird’s motion with its heavy body high up through the sky.”23 Growth is akin to the avian flight, in that it also destines the relatively heavy body of the plant, pertaining at once to the earth and to water, to the airy expanses above. The augmentative faculty operates contra natura, which is why it earns the standing above its nutritive counterpart. Not only does it organize the forces of nature, but it also opposes these forces, attesting to the interference of something that comes from the outside and remains inexplicable within the mechanical ordering of the elements. This external interference is, for Avicenna, an indelible imprint of the soul, thanks to which the excessive matter that comprises the plant submits to the impositions of form.
Nāmīa, or the faculty of augmentation, stands higher on the ladder of the vegetal soul for yet another reason: it sets its sights on perfection. We have already seen that growth entails an increase in bodily dimension in the right proportion, and it is this measured and balanced augmentation that would permit it “to achieve perfection.”24 Now, balance and proportionality are indicative of matter’s refinement, just as disorder and excess are the barometers of its unpreparedness for the reception of form. Insofar as growth abides by the teleological ideal of perfect proportionality, it (1) moderates the excessive ontology of plants and (2) boosts the formative drive of the soul at the expense of crude matter. Yet the conceptual limit of growth is that, along with nutrition, it serves a mortal individual growing being, not the species as a whole. Even if it strives toward the end of perfection, it is but a means for the higher ends of the generative faculty. Indeed, growth is a sort of go-between, bridging the lowest and the highest layers of plant soul,25 much like the plant itself in its capacity of an intermediary between the inorganic and the organic worlds.
The generative faculty (mawallida) houses a spark of divine, creative, form-bestowing force: “The reproductive faculty gives the matter the form of the thing.”26 Rather than replace “the loss incidental to the process of life” within an organism, it substitutes the whole creature with another like it. While the nutritive faculty transforms difference (nourishment) into sameness (the nourished), and while the faculty of growth augments the same (bodily extension) in the right proportion, mawallida articulates sameness and difference in a more complex constellation.
First, the reproductive faculty is the home of potential similarity, which can be actualized through its mixture with other bodies.27 Second, swerving away from the other two faculties shared equally by all nourished-growing beings, mawallida is unique to each self-reproducing species, not to mention the fact that it is split between sexual and asexual reproduction. As Avicenna writes: “We find them [living beings], beside having the obtaining of nourishment in common, to have growth also in common, but to differ in the propagation (of offspring), since there are, among growing things, such as do not beget.”28 On the one hand, asexual reproduction falls under the category of growth, because it is conceptually indistinguishable from the continuation of existing matter. True “begetting,” on the other hand, bears a new form, which potentially resides in the begetter. For these reasons, difference and identity cohabit in the generative faculty of the vegetal soul.
None of the above renders the formative capacity of plants commensurate with the souls of animals, let alone those of humans. “The animal faculties in their entirety,” Avicenna concludes, “are served by the vegetable faculties, of which the reproductive is the first in rank and the highest one.”29 Just as the mechanical forces of nature are the vassals of the vegetal soul, and just as within this soul there is another hierarchy based on feudal relations of superiority and subordination, so the plant kingdom and the vegetal faculties are the instruments of animals and of other souls moved by the power of volition. At this point, the historico-political analogy exhausts itself. In a feudal society, vassals exchanged their obedience for protection by powerful lords, a benefit squarely denied to plants. When it comes to the feudalism of the soul, what do the vegetal faculties—particularly those pertaining to the plants themselves—gain from their subservience to the animal principle?
Today, pioneering authors, including Michael Pollan, contend that we’ve got the instrumentalization of plants by animals and humans all wrong.30 What if, they ask, we are actually used by plants to spread their progeny worldwide? Where would a humble potato be if it weren’t exported from southern Peru and northwestern Bolivia to the farthest corners of the world? What would the fate of celery be, had humans not carried its seeds from the Mediterranean basin where it had originated to the Americas and beyond? Do plants and their “psychic faculties” put up a pretense of obeying the animal and human masters, whom they secretly use for their own reproductive ends? Or are plants, perhaps, neither subservient nor superior to animals and humans but deserving of an equal status in the republic of the living?
Under no circumstances would Avicenna respond to these questions in the affirmative. But he does inadvertently throw the fastidiously constructed hierarchy of the soul into disarray by pointing out a matter of profound “agreement” between plants and animals. It turns out that the two kinds of creatures share “the power of impulsion…more widely embracing than the power of perception.”31 The will of the animal corresponds to the plant’s “adaptation for attracting such foods as are useful and pushing off such that are harmful and incompatible,”32 except that the former resorts to motion, aided by perception, as a means of pursuing its interests and fleeing from danger. The absence of locomotion does not prevent plants from being impelled toward their goals without perception, which is one among many tools in the arsenal of the living for attaining their aims.
So far, so good. But Avicenna makes an unwarranted logical leap as soon as he classifies plants in a paradoxical group of insensate living beings. He suppresses the idea that perception through animal sense organs is not identical to sensation as such. Let us assume that the so-called distance senses of vision, hearing, and so on are germane solely to those animals that are able to dash in an instant toward a far-off source of food or run away from a predator. Still, other kinds of sensitivity would be indispensible both to sessile animals and to plants, if they are to determine whether or not they have reached the target toward which (or away from which) they are impelled. It is folly to think that being sensate is the function of the nervous system alone. “Insensate living beings” is a contradiction in terms, because the life of the living requires a high degree of discernment to preserve and promote itself.
Avicenna’s correct intuition about the plant’s power of impulsion should have prompted him to explore the murky terrain of vegetal sensitivity. It did not. Instead, the philosopher was forced to concede an unsettling similarity between the plants and the stars, which were also negatively defined as “insensate living beings”: “As for the starry firmament and plants, the feeling power and the imagining power have not been imparted unto them, even though each one of them has a soul and though it has life: the firmament has not these powers, because of its loftiness; plants have them not, because of their abasement in comparison to it.”33 Replicating the Aristotelian “beasts and gods” who lead an essentially apolitical life, Avicenna’s plants and planets live without sensation below and above the thresholds of animal and human existence, respectively. Only those beings do not need the powers of feeling and imagination that are either too deficient or too self-sufficient to pursue their goals. The uppermost and the lowest strata in the hierarchy of the living come together in the region of life scarcely comprehensible from the human point of view and, as a result, are showcased in negative terms: “insensate.” So much so, that the insensate life of plants is just one of two exceptional cases where Avicenna accepts a constitutively negative definition as entirely satisfactory.34
Another wrench stuck in the Avicennian hierarchical machinery makes the plants’ inferior status and their real capacities less and less compatible. What I have in mind are the correlates of the vegetal faculties in the spheres of perception and thinking. In The Canon, Avicenna likens the “natural forces” organized by the nutritive faculty, as well as the augmentative and generative faculties, to mental processes. To wit, the force of attraction is equivalent to perception, retention is memory, transformative power refers to cogitation, the force of expulsion corresponds to expression, the augmentative faculty is translatable into the acquisition of knowledge, and the generative faculty is tied to inventiveness and creativity.35 Such is Avicenna’s plant-thinking in a nutshell. Well in advance of Spinoza’s Ethics, physical processes and the tendencies of “the lowest” soul are interpreted as modes of thinking wholly under the sway of matter, unfiltered through the purifying form of (abstract) thought. By absorbing and retaining water and solar radiation, the plant “perceives” and “remembers” the liquid and sunlight; by growing, it acquires the “knowledge” of its environment, exploring the locale’s most beneficial, resource-rich niches; by reproducing itself, it invents, each time anew, its genus…
And, vice versa, humans “think” by way of eating, drinking, and expelling the byproducts of nourishing substances, by growing and by having children, though the more rarified forms of thought are available to them, as well. Avicenna is certainly not alone among the philosophers in attaching a negative value judgment to these material modes of thinking. But we would be amiss if we were to disregard his emphasis on medicine with its concern for adjusting the material conditions of life, being, and thought so as to promote healing and individual well-being. In a markedly Plotinian language, we might say that Avicenna’s medical corpus is the place where abstract thinking cares for its material corollary, or where the rational soul worries about the vegetal soul within the human. It is not that, page after page in The Canon, the mind tries to cure the body. In this magisterial, albeit often flawed book, human thinking endeavors to optimize plant-thinking within us.
Despite this optimistic vision of collaboration among the different kinds of psyche, hierarchical classifications reassert themselves both within and between plant, animal, and human souls. Much revolves here around the extent of materiality’s predominance: the soul of plants is the lowest because almost completely enmeshed with matter, while the soul of humans is constituted by more formal structures and processes. But this simple bifurcation too is deceptive, since materiality creeps into human thinking, whereas formalism potentiates the generative aspects of plant-thinking. Within the mental faculties proper some—notably, perception—are engrossed in material reality, and others (inventiveness, creativity) facilitate the play, recombination, and emergence of forms. The hierarchy of the vegetal soul infinitely mirrors and is mirrored by an equally striated arrangement of the human psyche, with perception ranked below knowledge acquisition and inventiveness. For centuries after Avicenna this gradation of knowledge will be unquestioned; it is kept virtually intact as late as in Hegel’s phenomenology of Spirit, which commences with perception as the lowest and most vacuous form of knowing. And, in many quarters, it is still alive now, in the twenty-first century.
It appears, on the face of it, that the division of the psyche in Avicenna is Aristotelian through and through. But his is, in the best of cases, “Aristotelianism with a twist.” Or, more precisely, with twists. Quite blatantly, Avicenna begs to differ from his ancient Greek forerunner on the subject of plant soul’s simplicity—the thesis that it is the indivisible origin (the geometrical point) of life. In Avicenna’s thought, what Aristotle called tō threptikon brings together four disparate forces of nature that do not, as such, possess a soul. Furthermore, for the medieval thinker, vegetal soul in its totality is irreducible to one fundamental capacity to obtain nourishment, of which the rest would be more or less elaborate variations.36 Nor does Aristotle contend, as Avicenna does, that the soul penetrates the body from elsewhere, having originated outside the creatures it animates.37 Ernst Bloch’s praise of Avicenna’s “naturalism”38 sounds particularly suspect in this regard.
One of the twists in the philosophical plot that represents Avicenna as an Aristotelian has to do with the differences and divisions the former spliced into the vegetal soul. In the aftermath of Avicenna’s transformative reading of the Philosopher, the primordial level of the psyche is no longer imaginable as a pure and simple source equivalent to the geometrico-metaphysical point, which cannot be further subdivided into component parts. At the origin, there is no coherent unity—the ideal of all metaphysical philosophy. It’s a pity that while undermining a fundamental tenet of metaphysics the medieval thinker commits yet another cardinal sin. Organizing differences into hierarchical conglomerates, he sanctions the enduring oppression of the vegetal (as much as of nature) both within and outside of the human.
After learning that Avicenna conceptualized plants as insensate living substances, readers will greet with understandable suspicion the revelation that he deigned to include these creatures devoid of “the power of feeling” in his Treatise on Love. How is it possible for plants to love anything, if they are so deficient as to lack the entire emotive layer of the soul?
We should backtrack a little in our argument thus far, to pick up a clue to the nature of plant love. Recall that Avicenna has established the existence of the vegetal “impulsion,” presaging the will of animals, albeit acting without the assistance of perception. Plants are driven toward their goals and, finally, toward perfection by an impulsion that expresses their love, ‘ishq, a state much broader in scope than emotional attraction and attachment. In the words of Avicenna, “Every type of love has as object either something already attained or something which is still to be attained. Whenever the goodness of a thing increases, the merit of the object of its love increases also, and so does the love for the good.”39 It follows that the objects of vegetal love are life-sustaining nutrients, self-augmentation in growth, and the renewal of the genus through reproduction. Without either perceiving or understanding these objects (as a matter of fact, without relating to them qua objects), plants strive toward them, loving them with a love that is literally blind.
There might be more than one grain of truth in saying that plants are “water loving” or “sun loving” since these are things they strive to attain as nutrients guaranteeing the physical conditions for their existence. But the sense of love Avicenna alludes to is considerably broader than the colloquial phraseology would imply. Each faculty of the vegetal soul has its distinct goal, a unique perfection, and a peculiar kind of love. The plant is moisture and light loving inasmuch as it is reduced to its nutritive faculty, which is “the source of its desire for the presence of food in accordance with the need of matter for it.”40 We would not be off the mark were we to put this idea side by side with the Platonic, Plotinian, and Augustinian formulations of vegetal desire discussed previously. The gist of Avicenna’s Treatise on Love is, indeed, Neo-Platonic, as every brook, creek, and stream of creaturely love gushes into the great river of loving the pure good.41 But what plants have to offer to this great cosmic rush toward being and the good is not limited to a desire for nourishment. Their augmentative and generative faculties each contribute something to the meaning of love within the general ordo amoris.
The type of love “specific to the faculty of growth” is the plant’s “desire for the increase fitting the proportions of the body which is nourished.”42 Presumably excessive in their constitution, plants must practically discover a bodily equilibrium indispensible for the living. The love inherent in their growth affirms what is already in being and strives toward perfection, tied to the proportionality of the growing body. It is, therefore, compatible with the love of beauty in the sense of proportionality and with the love of existence wherein that entity which manages to strike the right physical balance within itself and with its environment conserves itself for the duration of its finite life. (An apt example of this from early modern philosophy is the Spinozan conatus.)
Whenever Avicenna writes about love, he presents a scenario where an imperfect being tends toward perfection, beauty, the good, incorruptible being, God…Nutritive and augmentative kinds of love cling to the finite creaturely existence of the vegetal, animal, and human lovers in the hopes of participating in that being which always is. Procreation, conventionally paired with love, fosters a more secure participation in the eternal, in that it no longer bets on the futile self-preservation of the living just as they are. The generative faculty responds to the need for the renewal of an organism not in itself but in another that issues from it. To this faculty is attached still another kind of love—“the desire to produce a new principle similar to the one from which it [a living creature] derives itself.”43 Generative love is the desire of the finite for infinity, or for a potentially infinite regeneration of the wellspring of its own life in another creature akin to the progenitor. What is reproduced is not just another celery plant that will germinate from a seed but a new principle, a fresh beginning, through which the same (genes, genus, and so forth) rejuvenates in a material substratum resembling that of the parent. The love of the generative soul emphatically says “yes” to being (ergo, to the good) by recommencing finite life after death, to which it denies the honor of having the last and decisive word.
All this is not to say that the three vegetal variations on love furnish a proof of exceptional plant agency. In Avicenna’s thought, love is not foreign even to inanimate objects, where matter yearns to receive form so as to “shy away from absolute non-being.”44 It is not limited to an affect experienced by living creatures; in the first and in the last instances, everything and everyone—including natural forces, vegetal, animal, and human powers—seek the Necessary Existent, or God, as the absolute good.45 The how of love, not the fact that it is experienced, is of the essence. The difference between modes of being is indexed to the diverse modes of loving the good.
If the how of loving matches the how of living (not to omit the inorganic kinds of being), then the loves of plants should be as excessive as their lives. According to Avicenna, in their aspiration to perfection, which ignites love, beings imitate the First Cause, the absolute good, the Necessary Existent, or God. By resisting nonbeing and staying at rest once they have been reunited with their proper elements, natural bodies, for instance, imitate the ideal immobility that typifies the object of their love. Now, plants emulate the First Cause in aiming to preserve the individuals and the species, “even though, in their beginnings, aims such as sexual intercourse and nutrition have no resemblance to It.”46 Like all other creatures, they imitate the Necessary Existent “in the aims of their activities but not in the origins,”47 but, contrary to other creatures, plants, as the first bearers of the generative faculty, ensconce the problematic of origination (generativity) in the aims of their activities. Blurring the distinction between the aims and the origins, they imitate the First Cause excessively, mimicking it in what it is not.
In Avicenna’s Platonic Aristotelianism, living creatures as well as inanimate objects are not impelled by a force emanating from the past of their origins but are moved from the future of their aims that invariably point the way to the good. All roads lead to Rome. Avicenna’s masterful fusion of Aristotle’s notion of the unmoved mover and Plato’s doctrine of love culminates in the observation that “that which moves the mover without undergoing change through intent and desire is the end and the objective toward which the mover aims. It is the object of love. And the object of love, inasmuch as it is the object of love, is the good for the lover.”48 Plants, too, love what is good for them and, therefore, in our terms, pursue their interests: to maintain themselves in being, individually and through their progeny. Seeing that Avicenna accepts the ancient equations of being with the good and nothingness with the privation of being (evil), the love of existence in everything that lives connotes a love of the good and a resistance to evil. When plants grow toward the light of the sun, they are moved from the outside, in parallel to the good that animates its lovers from a certain “end” of their activity, in Avicenna as well as in Plato. In other words, when plants are said to love light and moisture, the real objects of their love are being and the good. And we, humans, cannot help but recognize bits of ourselves in their conduct and love this vegetal love.
As I’ve mentioned, for Avicenna, neither plants nor other creatures are the exclusive subjects of ontological love. Inanimate entities also cling to being, resisting entropy and yearning to find rest in their respective elements. This caveat should not be used to deprive plants of their claim to moral considerability. If anything, it makes Avicenna-inspired environmental ethics capacious enough to encompass entire ecosystems, such as rivers rushing to be reunited with the watery element, which they love, in the sea. That inanimate objects also love being after their own fashion does not detract from the love of eternity and of existence that permeates all three layers of plant soul.
In one of the most poignant moments in the Treatise on Love, Avicenna construes the human propensity to kiss and embrace as our affirmation of the loving proximity to and the desire for a union with one another.49 “Tree-huggers” are generally derided for inappropriately transferring these affective gestures onto the flora and the environment as a whole. But the kiss and the hug need not be literal. Our drawing near the environment, whether in experiencing concern for its future or in understanding its constituents as so many imitations of and loving approximations to the good, amounts to a virtual embrace of the world. “What do plants love?” is much more than a question; it is a symbolic kiss and hug given to the being of plants.
At the opening of A Compendium on the Soul, Avicenna exhorts his reader to pursue with the utmost rigor the ancient injunction to “know thyself.” Avicennian self-knowledge is, in effect, tinged with a medieval flavor, in that it is sought not for its own sake but with the view to gaining insight into the nature of God, whose traces we are. Between faith and knowledge, there is, in this regard, a phenomenal consensus: “wise men and pious saints” proclaim, in a single voice, “Whoso Knoweth himself, Knoweth his Lord.”50
What form does knowing oneself take in a soul, whose parts are lined up in a hierarchical chain of command? If humans are the composites of vegetal, animal, and rational (speaking) capacities, then the awareness of all these, working in concert, is indispensable for their genuine self-knowledge and, by extension, for the knowledge of God. But is it really possible to know how the nourishing, growing, and generative capacities set themselves to work in our everyday life? Can we ever be fully alert to the way the plant in us grows, flourishes, and withers away? To know ourselves, we must pay heed to the physiology of the body and to the unconscious—those vegetal dimensions of our existence that dodge our senses and conscious grasp. It could well be that Avicenna’s scrupulous medical researches were, at bottom, ways to grapple with these most difficult aspects of self-knowledge. Even so, no investigation—no matter how painstaking—is in a position to expose the complete workings of the vegetal soul without losing track of their unconscious character. Hence, the aporia (the roadblock) of the simultaneous necessity and impossibility of knowing our “vegetal” self at the extreme limits of self-knowledge.
The aporetic situation into which plant soul has forced Avicenna and us goes from bad to worse, seeing that the true destination of self-knowledge is not this very self, but God. So, if God is ultimately unknowable, it is not only because His infinity overwhelms our finite minds but also because we cannot fully comprehend ourselves: the vegetal part of our psyche orchestrates our growth, the processing of nutrients, and sexual maturation largely unbeknownst to us. Conversely, what we do grasp about the operations of the vegetal soul feeds directly into our knowledge of the divine. Medical research is, therefore, replete both with psychological and theological overtones. Avicenna himself alludes to this odd conceptual knot of medicine, philosophy, and theology on the pages of A Compendium:
I have also read that this saying [“Know thyself,” etc.] was engraved in the façade of the temple of Aesculapius, who is known…as one of the prophets and whose most famous miracle is that he was wont to heal the sick by mere loud supplication; and so did all priests who performed sacerdotal functions in his temple. From him have philosophers got the science of medicine.51
The essential incompleteness of our self-understanding has been already foretold in The Canon, especially in the comparison it makes between the augmentative faculty of growth and acquisition of knowledge. On the one hand, thanks to the hindsight afforded by the Age of Enlightenment that stretches between Avicenna and us, this analogy seems to support a belief in unbridled progress. The sky is the limit to vegetal growth and to knowledge acquisition, soaring up to airy realms on the wings of spirit…(Lest we get carried away with this protoidealism, the analogy also suggests that our systems of knowledge are plantlike, in that they can wither away, die, and serve as fertilizers for subsequent generations, which is the fate of all growing things.) On the other hand, and more accurately, both growth and knowledge extend toward their ends, the sun and the good, without ever reaching these objects of their love. Rather than instigate the march of progress, their incompletion foregrounds an unbridgeable distance, the abyss between growing-knowing beings and that toward which they grow or that which they wish to grasp knowingly. It measures the degrees of separation between plants and the sun, us and the good, us and God, us and ourselves.
In defiance of the laws of physics, persistent growth and knowledge seeking actually increase these various distances, not so much by laying bare what we do not yet know as by situating the conditions of possibility (which are, at the same time, the final objects) of growing and knowing outside the ambit of these activities. Knowing that we are, among other things and in our innermost depths, plants is knowing that we will never know ourselves (and God) absolutely. No system of psychological knowledge, however exhaustive, will fill these gaps. “Know thyself!” will not even be heard properly unless it is accompanied by the Socratic profession of not-knowing—an aporia, all over again. The plant in us is our opaqueness to ourselves, our distance from God, our unconscious, if you will. And it is, at the same time, what is exceedingly near: our body, love, and being on the hither side of abstract knowing.
