A New Leaf: Is It Time to De-objectify Plants in Private Law?

Abstract

In civil law jurisdictions, plants have traditionally been classified as ‘objects’ (or ‘things’) under private law, reflecting an age-old tendency, certainly in the Western world, to underestimate and undervalue plants. Recent legal debates increasingly acknowledge the special nature of plants. Perhaps the most eye-catching debate in this context is the one on Rights of Nature, which have much potential but pose some practical and conceptual challenges. We propose an additional way of acknowledging the special nature of plants in a legal context: de-objectifying plants in private law and thereby explicating that they are not mere objects. Numerous civil codes already separate animals from objects, often – though not exclusively – based on the sentience of animals. Recent scientific research suggests that plants may be sentient, too. We aim to open the debate on the de-objectification of plants, based on their sentience, in civil codes as a feasible and unobtrusive way to acknowledge in law that plants are living beings, and more than mere things.

1. Introduction

Plants can see. They can count and communicate with one another. They are able to react to the slightest touch and to estimate with extraordinary precision. Such statements, put baldly, seem almost fanciful not to say exaggerated to the point of falsity. Yet while some of these abilities have only recently been identified by botanists, the evidence for others is known to anyone who has the slightest acquaintance with plants– and that must surely mean almost everyone.

David Attenborough ¹

Many would agree that plants – such as trees, shrubs, grasses, ferns, flowers, mosses – are more than just ‘objects’ or ‘things’,² in the common sense of those words.³ Yet, in private law, in many – if not most – civil law jurisdictions,⁴ this is not the case. Within private law, the word ‘object’ commonly does not only refer to inanimate objects, such as scissors, screenplays, stairs, skyscrapers, and satellites. Plants, too, together with animals and other non-human lifeforms, have long been ‘objects’ in private law.⁵

To be sure, across the world and throughout history, different societies and communities have (had) different views regarding plants. For example, ‘Eastern’ religions have been considerate of plant life ‘for millennia’, Marder indicates;⁶ and, as Calvo and Lawrence write, ‘[a]nimistic societies in pre-Christian Europe or in different parts of the world today’ regard plants as ‘entities with potency and meaning’, and various Indigenous cultures – such as the Māori, certain Native American groups, Indigenous Amazonians, the Inuit, and Indigenous peoples of subarctic Canada – view plants as, for instance, ‘kin with a shared heritage’ or ‘“persons” with souls of equal standing’.⁷

The private law distinction between humans and objects, common in many, if not most, civil-law countries, is particularly sharp in European civil law societies.⁸ While a sharp distinction between a human being and an inanimate object still seems perfectly understandable, such a sharp distinction between a human being and other living beings – including plants – is arguably less defensible today. The division between humans on the one hand, and all other beings on the other, stems from the age-old idea, prominent in the history of Western thought,⁹ that humans are separate from ‘the external, natural world’,¹⁰ which exists for humans to appropriate;¹¹ as well as from the idea that humans – endowed with (supposedly) uniquely human characteristics such as intelligence, language, and reason – are the only lifeforms that can be granted legal subjectivity.¹²

However, as a result of scientific discoveries such as the theory of evolution by natural selection, the supposed uniqueness of humans has been challenged more and more convincingly. It has become common scientific knowledge that humans are more related to, as well as more similar to, other animals, and even to plants, than had long been assumed, and, furthermore, that humans are far more dependent on the web of nature than was previously known.

Law, commonly changing in the wake of scientific discovery,¹³ has followed suit. There are several interesting and important legal debates that are relevant to the question of the legal status of plants. The animal rights debate is one, and the more recent debate on Rights of Nature (RoN) is another. Since the adoption of the first RoN law in the United States (US) in 2006,¹⁴ this approach has become more and more popular. As Kurki writes, ‘[i]t is increasingly taken for granted that rivers and other natural entities can be legal persons and right holders’.¹⁵ While we sympathize with the RoN movement, given its attempts to incorporate ‘Nature's rights … into a broader rights framework for governing the planet sustainably’,¹⁶ we are also conscious of the (possible) drawbacks to this approach.¹⁷ These vary from ‘conceptual deficiencies’¹⁸ to the contention that, say, a tulip tree (Liriodendron tulipifera) can never reciprocally recognize the rights of others or have legal responsibilities.¹⁹ Furthermore, RoN requires many advocates, in both the ‘nature's rights’ model (‘anyone can speak for nature, but is not obliged to’), as well as the ‘legal personhood’ model (‘specific guardians are obliged to represent the ecosystem at all times’).²⁰ In the courts there have hitherto been some ‘arbitrary’ results, ‘ungrounded in any meaningful criteria’.²¹ Also, there may be serious political hurdles to clear in certain jurisdictions when it comes to bestowing something as lofty as rights on non-human organisms such as plants. The above does not suggest that efforts to extend RoN to non-human organisms should be abandoned, rather, that additional approaches are worth exploring.

In this article we suggest an additional approach to a changing legal status for plants, one that confronts the aforementioned designating of plants as ‘objects’ in private law. We build this approach on another recent legal development pertaining to animal welfare and biodiversity protection: the de-objectification of the animal in private law.²² In recent years, the long-standing and sharply drawn private law distinction between humans and non-human beings has become blurred in several jurisdictions. Over a dozen European countries have amended their civil codes either to state explicitly or to imply that animals are, in fact, quite different from objects.²³ Bernet Kempers explains that a new private law category has now emerged, ‘that lies somewhere in between the person and the thing’.²⁴

Some scholars have argued that the placing of animals in such an in-between category is purely symbolic, in that it does not readily appear to have material legal effects on animals.²⁵ However, Bernet Kempers cautions that:

the possible implications of the development should not be underestimated. Even though it is certain that the provisions that differentiate between animals and legal things do not vest the animal with legal personality, the new status may influence the way animals are being addressed in various areas of private law and can possibly be construed as a limit to the rights of persons.²⁶

Furthermore, as Burdon and Williams have noted, in the context of RoN, bestowing rights not only provides governmental protection but also visibility, changes in consciousness regarding the something or someone that has been given rights, and increased respect for that same something or someone.²⁷ The same could well be argued with regard to de-objectifying living beings in private law.

In this article we want to open the debate on de-objectifying plants. Based, inter alia, on recent scientific discoveries on plant sentience, what are some of the most important arguments for the de-objectification of plants in (civil law) private law? Plant sentience is relevant because sentience in some (or all) animals has been invoked in several jurisdictions as an important argument in favour of de-objectifying animals.²⁸ Other or additional arguments to support the de-objectification of animals have also been put forward: an animal's intrinsic value, or its dignity, or the fact that an animal is a fellow living being.²⁹

Plants, like animals, are different from inanimate objects. Yet, there appears to be no noteworthy consideration of that fact in private law. Academic legal scholarship appears to be incomplete on this issue;³⁰ to our knowledge there is no academic literature that considers the de-objectification of plants in private law from a policy-based approach – let alone any realization of such policy. We believe that, compared with the rights-based approach, which can in some ways be more consequential but also more controversial, the de-objectification of plants in civil codes presents a more accessible opportunity that is both meaningful as well as politically and legislatively feasible. It could influence the way in which plants are addressed in private law and protected by public law,³¹ limit the rights of persons vis-à-vis plants, and increase the visibility of and respect for plants in the eyes of citizens. Subsequently, these developments might lead to better protection for plants on the grounds of their instrumental value to humans, and/or on the grounds of their own sentience, value, dignity, aliveness, and so forth.

To firmly root our argument, this article branches out as follows. Firstly, we discuss the de-objectification of animals in private law by considering several civil codes that distinguish animals from objects. This section is more doctrinal in nature, looking at black-letter law, parliamentary deliberations, jurisprudence, and legal scholarship.³² Secondly, we present a brief overview of findings in scientific research on plant sentience in order to substantiate the argument that plants may also be said to possess sentience. This ‘auxiliary’ interdisciplinary use of the natural sciences, more specifically plant science, is relevant because it provides a scientific foundation for the policy and legal debates we hope to instigate.³³ Thirdly, we address some of the different ways in which the legal position of plants is currently discussed, in both academic legal literature and other relevant sources. Finally, we conclude by arguing that it is high time to seriously consider de-objectifying plants in civil codes,³⁴ based on the recognition of some degree of sentience in plants, as well as on other rationales.

2. De-objectifying Animals in Law

Before we consider the de-objectification of plants, we will look at its quite recent precursor: the de-objectification of animals in several European jurisdictions. Bernet Kempers explains that for animals a new ‘category that lies in between’ (human) persons and mere corporeal objects has materialized in private law.³⁵

As mentioned, this de-objectification is a clear break with long-standing Western legal tradition, in which a sharp distinction exists between ‘human culture and the external, natural world’.³⁶ In this tradition, only by appropriating animals and plants does a human bring those animals and plants ‘into the legal sphere’, where they subsequently become objects of property rights.³⁷ Presently and generally, Bernet Kempers writes, an animal in the eyes of private law ‘is entirely defined by its status as property’.³⁸ Burdon and Williams also summarize that ‘Western legal systems treat the environment and non-human animals as property that can be bought, sold and used by humans’.³⁹ Eskens notes that since antiquity, ‘pretty much all philosophers, theologians, legal scholars and politicians’ have adhered to the idea that humans are ‘the only creatures to which a State could have obligations’, as humans supposedly are unique beings, endowed with uniquely human characteristics such as intelligence, language, and reason.⁴⁰

Bernet Kempers writes that the relegation of animals (and, we might add, plants) to the status of things to be exploited is arguably one of the causes of the current climate and biodiversity crises.⁴¹ The centuries-long reduction of animals and plants to mere objects in private law could thus be viewed as one of the noteworthy factors behind the materialization of the Anthropocene.

2.1. Legal Consequences of De-objectifying Animals in Private Law

The new in-between category that de-objectifies animals in private law is interesting for legislators, as it can acknowledge both the special nature of animals – because of their sentience, their dignity, their intrinsic value, or other reasons⁴² – as well as the needs of sectors that require the use of animals as objects (including buying and selling them), such as agriculture, biomedicine, and the pet industry.

Acknowledging in private law that animals are different from mere corporeal objects is not the same as vesting animals with legal personality and rights. Despite no longer being considered objects, animals can still be, and still are, legally exploited by humans. It has been argued, therefore, that de-objectifying animals in private law is merely a symbolic act. Jansen, for instance, refers to Article 3:2a of the Dutch Civil Code (DCC), which has de-objectified animals in Dutch private law since 2013.⁴³ Article 3:2a DCC states that ‘animals are not things’, but then immediately adds that ‘provisions relating to things are applicable to animals’.⁴⁴ In other words, according to Dutch law, animals are more than mere objects but, legally, they can be considered as if they are objects.⁴⁵ Jansen argues that the Dutch legislator thus immediately ‘takes away … what he gives’, and that such an in-between category, therefore, has ‘zero legal consequences’.⁴⁶ Similar objections have been voiced regarding the French de-objectification of animals.⁴⁷

Yet, it could also be argued that this new in-between category is, in fact, more than merely symbolic. Burdon and Williams’ arguments in a different context (bestowing actual rights) are, as mentioned earlier, also applicable to de-objectifying an animal or plant in private law; de-objectification could not only (help to) provide governmental protection but also visibility, changes in consciousness regarding the living being that has been de-objectified, and increased respect for that same living being.⁴⁸ As mentioned, Bernet Kempers states that de-objectifying animals in private law is not as meaningless as it might appear, for it can affect the position of animals within private law and function as a ‘limit to the rights of persons’.⁴⁹

In some divorce cases, for instance (such as in France and Belgium), animals have been considered separately from the other objects in a household based on the affectionate bonds humans can have with them.⁵⁰ In other divorce cases (such as in Germany and the Netherlands) animals have been considered separately from other objects in a household because of the animal's own interests – to assess, for instance, whether a party is equipped to properly care for the animal.⁵¹ De-objectifying animals can also play a role in determining the compensation for ‘damage’, as well as in the context of executing seizure for debts.⁵² Although many of these cases predate the establishment of an in-between category in the applicable civil code,⁵³ Bernet Kempers argues that creating such an in-between category in civil codes ‘might better be regarded as a consequence; a way to make a trend explicit that is already going on’.⁵⁴

2.2. Rationales for De-objectifying Animals in Private Law

Several European civil codes grant a special position to animals. The civil codes of Germany, Austria, Switzerland, the Netherlands, and the Czech Republic state explicitly that animals are not objects.⁵⁵ Civil codes of various other European countries (Lithuania, Hungary, France, Estonia, and Romania) more implicitly suggest a special position for animals.⁵⁶

The underlying reasoning varies across the different jurisdictions. The Portuguese Civil Code states that animals ‘are living beings endowed with sensitivity and subject to legal protection by virtue of their nature’.⁵⁷ In several other civil codes the sentience of animals is used as a rationale for de-objectification. The Belgian Civil Code states that animals have sentience (gevoelsvermogen) and biological needs.⁵⁸ In France, too, the Civil Code explicates animal sentience (sensibilité).⁵⁹ However, sentience is not always the rationale for conferring a special status on animals. The German Civil Code, for example, simply considers animals to be non-objects, without acknowledging any special capacities,⁶⁰ although the German Animal Protection Act does state that animals are our ‘fellow beings’.⁶¹

With regard to the possible de-objectification of plants, the Dutch parliamentary debate on the de-objectification of animals is particularly noteworthy. In 2013, the DCC took inspiration from the German Civil Code for the addition of Article 3:2a DCC, according to which ‘[a]nimals are not things’.⁶² The intrinsic value of animals, first recognized in the Netherlands in 1981, is the basis for this amendment.⁶³ During the parliamentary deliberations on the amendment, Gerda Verburg, who at the time was the Dutch Minister of Agriculture, Nature and Food Quality, received a question from sceptical members of the conservative-liberal People's Party for Freedom and Democracy (VVD). In an attempt at a reductio ad absurdum reminiscent of Thomas Taylor's Vindication of the Rights of Brutes,⁶⁴ they cynically asked whether perhaps a similar amendment should also be introduced for plants, while they were at it.⁶⁵ Verburg nipped this discussion in the bud by responding that ‘plants are living things, too. They are, however, not living beings with sentience. Plants should, therefore, not be equaled to animals’.⁶⁶

We submit that this position needs to be reconsidered. In the next section we argue that scientific discoveries, especially in recent years, have convincingly called into question the assumption that plants are not sentient beings. If sentience is one of the main arguments for de-objectifying animals in private law, then the de-objectification of plants would not be so absurd at all.

3. Rationales for De-objectifying Plants in Private Law

A number of recent findings in plant science require us to take the idea of plant sentience seriously. This section gives an overview of such findings and other relevant considerations. Firstly, we briefly discuss how crucial plants are for human life and wellbeing, that is, their instrumental value.⁶⁷ Secondly, we address ‘plant blindness’, a common characteristic of human beings. Thirdly, we present some scientific findings on a variety of behavioural expressions of plants that may be interpreted as expressions of plant sentience. Fourthly, we consider speculations on whether plants could possess their own form of intelligence. Finally, we briefly introduce alternative rationales for de-objectifying plants, should acknowledging plant sentience (let alone, plant intelligence) be considered a bridge too far.

3.1. The Instrumental Value of Plants

According to the botanist Timiryazev, plants are ‘the intermediary between … energy in the organic world and the sun, the universal source of energy’, facilitating animal life through the photosynthetic creation of oxygen and through ‘the energy of the sun stored up by the plant’ being consumed directly or indirectly by animals.⁶⁸ Plants have provided energy (fossil or ‘fresh’) ever since humans first learned to control fire.⁶⁹ They are the foundation of the entire food chain, and they are the source of many essential medicines.⁷⁰ The vertical growth of plants has been foundational for the ‘evolution of the brains and particularly the neocortices of our [arboreal] ancestors’, and therefore ultimately of human intelligence.⁷¹ Plants increase the human attention span, reduce stress in humans, and aid humans in recovering from illness.⁷² Traffic accidents occur less in streets that have trees, and suicide and violent crime occur less in urban environments with ample green spaces.⁷³ Many important scientific discoveries that became famous only after their application on humans or other animals were actually first made by experimenting on plants (such as genetics, cellular biology, and ribonucleic acid (RNA) interference).⁷⁴ Plants also absorb pollutants.⁷⁵ Some plants can even accumulate such high amounts of heavy metals, like nickel and lithium, that ‘agromining’ might have a bright future: plants as ‘hyperaccumulators’ could be used either to restore polluted soil or to harvest metal.⁷⁶ Last, but certainly not least, their capacity to remove carbon dioxide (CO₂) from the atmosphere makes plants crucially important for humans (and other forms of life) in the Anthropocene.

Even though these and other arguments would support – and have already supported – certain forms of legal protection for plants on the basis of instrumentality alone, humans still tend to ignore the importance as well as the abilities of plants. This ignorance is so remarkable, considering the facts, as to warrant being called ‘plant blindness’.⁷⁷

3.2. ‘Plant Blindness’

Discoveries in plant science indicate that humans are not as justified as many (though certainly not all)⁷⁸ may think in placing themselves above plants in the grand scheme of things. Author and journalist Pollan writes that ‘only human arrogance … keeps us from appreciating [the] intelligence [of plants]’.⁷⁹ Mancuso and Viola also emphasize, in their book Brilliant Green,⁸⁰ the ways in which humans have for millennia looked down upon the plant world as being somehow less evolved. For example, Noah in the biblical tale did not find it necessary to take plants with him on the Ark;⁸¹ Aristotle classified plants – which he considered to be ‘deficient animals’⁸² – as having a ‘low-level soul’, which acknowledged the ability of plants to reproduce but not much more;⁸³ and Islamic religious art largely avoids the representation of sentient living beings, yet frequently features plants and flowers.⁸⁴ Even Linnaeus and other scientists of his time, when observing the carnivorous behaviour of certain plants such as the Venus flytrap (Dionaea muscipula), refused to acknowledge that such plants actually lured, trapped and ate animals, preferring instead a host of peculiar explanations such as that ‘the insects didn't die at all, … they chose to remain inside the plant of their own volition and for their own convenience’,⁸⁵ or that when trapped animals ‘didn't free themselves, it was because they were old or had chosen to die’.⁸⁶ Calvo and Lawrence write that ‘[u]ntil the nineteenth century, many scholars vehemently denied that plants were sexual organisms at all’. They furthermore refer to a 1981 study from New Zealand that ‘found that many children did not even consider an organism to be a “plant” unless it had flowers’,⁸⁷ something that, we believe, might also be apparent in the commonly used term ‘flora’ for plants both with and without flowers.⁸⁸

Constitutional law scholar Tribe writes that ‘[n]o one should suppose that this bias is a shallow one or that it can readily be eliminated’ as its ‘roots lie deep within the Western philosophical and theological tradition’,⁸⁹ and philosopher Marder writes that ‘[d]eep psychological resistance prompts us to dismiss the mounting scientific evidence that challenges readymade conceptual molds, into which plants have been slotted thus far, in favor of the inertia of habit and the comfort of “common sense”’.⁹⁰

Botanists have long had a name for this common attitude that humans have towards plants: ‘plant blindness’.⁹¹ Botanists Wandersee and Schussler, Grosscurt writes, ‘concluded [that there is] a human incompetence, a blindness to vegetation that is comparable to color blindness’.⁹² Darwin himself was already aware of this widespread plant blindness in humans. Although he thought highly of plants, finding them ‘the most extraordinary living things he had ever encountered’,⁹³ he was nonetheless reluctant to introduce his thoughts on the abilities of plants because he had already bruised the human ego with his theory of evolution by natural selection.⁹⁴

This tendency in humans is unsurprising given the fundamentally different evolutionary paths that plants took from animals (including humans). When comparing the earliest plant and animal cells, Mancuso and Viola write, one finds that those were ‘really very similar’.⁹⁵ Yet, generally, plants went on to lead lives rooted in the ground on a fixed location (becoming so-called ‘sessile’ organisms), while animals went on to lead ‘nomadic’ lives, moving around (‘motile’ organisms).⁹⁶ Thus, animals needed to be able to carry all their organs with them while plants evolved a modular body without ‘central, irreplaceable organs’, which is fundamentally different from the human and non-human animal body.⁹⁷ Also, because of their rootedness, as well as their relatively slow tempo of movement, plants appear to human perception to be almost completely immobile and thus inanimate – although sped-up visual recordings of plants clearly undermine that supposition.⁹⁸ These and other fundamental differences from animals help to explain why humans exhibit plant blindness.

On our planet, which probably began to turn green around 500 million years ago,⁹⁹ plants are still overwhelmingly dominant, growing on ‘every terrestrial environment’,¹⁰⁰ and composing approximately 80% of the biomass on Earth.¹⁰¹ This dominance indicates great adaptability and thus in certain ways a ‘superior problem-solving ability’.¹⁰²

In the next paragraph we sum up several of the most important arguments that plant biology offers in support of plant sentience. This supports our conclusion that because plants may possess sentience, there should at least be a serious parliamentary deliberation on whether plants should be distinguished from mere objects in private law, in the same way that animals in some jurisdictions have already been distinguished.

3.3. Plant Sentience

A phrase like ‘sentience of plants’ may seem to belong less in an academic legal text and more in a work of science-fiction, such as The Thing from Another World (1951)¹⁰³ about an extraterrestrial vegetable lifeform bent on world domination; or The Happening (2008)¹⁰⁴ about plants conspiring to induce millions of people worldwide to take their own lives and, in doing so, alleviate the pressure humans exert on the natural environment. However, it is science proper, and not science fiction, that allows for the sentience of plants to be seriously considered by legal scholars, as is increasingly the case.¹⁰⁵ This influence of scientific discovery on legal thought makes sense, since – as Judge Barbara Jaffe said in court when she presided over a US case involving the grant of habeas corpus to chimpanzees (in that they are highly intelligent, self-aware, and empathic animals) – ‘the law evolves according to scientific discovery’.¹⁰⁶

In this subsection we will refer to a variety of scientific findings on plant behaviour. Whether the (intentional) behaviour of plants proves sentience is yet to be agreed. This was affirmed in a recent special issue of the journal Animal Sentience on plant sentience.¹⁰⁷ In this source Segundo-Ortin and Calvo argue that ‘there is still much to be discussed before it can be accepted that plants feel, but we would disagree with those who would rather deny the possibility of plant sentience altogether’.¹⁰⁸ The 29 commentary articles in the special issue demonstrate that whether plant sentience is accepted depends largely on how ‘sentience’ is defined and studied; for as long as methods of studying animal sentience dictate studies on plant sentience, the results will be dismissive.¹⁰⁹ Accepting the plausibility of plant sentience requires accepting the possibility that sentience does not necessarily require typical animal properties such as a central nervous system.¹¹⁰ We concur with Segundo-Ortin and Calvo and acknowledge that there is a degree of uncertainty over plant sentience. Still, given recent findings in plant science, we consider that one should take seriously the possibility of plant sentience and its implications for private law.

Plants appear to have all five senses, just like humans, albeit in their own particular way.¹¹¹ On top of these familiar senses, plants have ‘at least fifteen’ other senses, such as the ability to ‘calculate gravity, electromagnetic fields, and humidity’ and the ability to ‘analyze numerous chemical gradients’.¹¹² When those chemical gradients indicate a pollutant, the plant roots ‘distance themselves as soon as possible’.¹¹³ Certain plants such as Mimosa pudica (better known as the Shameplant, the Sensitive plant, or the Touch-me-not plant), can even react to being touched,¹¹⁴ and in doing so ‘distinguish among different stimuli, and even change its behavior, no longer remaining closed once it learns that a stimulus isn't dangerous’.¹¹⁵

This assertion that plants can learn was already supported by experiments in the 19^th century with Mimosa pudica. At first, the plants closed in reaction to the heavy shaking that occurred when the cart in which they were transported was pulled along over the cobblestones in Paris, but after some time they remained open. Having learned that they were not in any danger, they no longer wasted energy ‘by pointlessly closing their leaves’.¹¹⁶ Many plants can ‘acquire learned behaviors … in a matter of seconds’ and can ‘remember what has been learned for several weeks’.¹¹⁷ Birch trees can even remember something they learned for up to five years.¹¹⁸ Plants can recognize attacks by herbivores and react accordingly, for example, by ‘making their leaves indigestible or even poisonous to the insect aggressor’.¹¹⁹

Plants sleep; the leaves of many plants fold inwards at night to reduce their nocturnal activity.¹²⁰ In fact, the correlation between the sleep movements of plants and darkness has invoked the suggestion that plants possess ‘an internal mechanism for measuring time’.¹²¹

Many experiments in molecular biology are carried out by growing plants in transparent gels. This leads to the roots being constantly exposed to bright light (as opposed to the darkness of soil). The plant arguably becomes stressed, rapidly growing its roots in a vain attempt to reach darkness.¹²²

Plants can also recognize their own kin and take caution not to frustrate one of their own as they would other plants in the struggle for sunlight, water, and soil nutrients.¹²³ Examples include not overgrowing the roots of a related plant or, in a phenomenon called ‘crown shyness’, not interfering with their sunlight.¹²⁴ Through underground mycorrhizal networks,¹²⁵ stronger fir trees have been observed helping carbon-deprived kindreds by supplying them with carbon.¹²⁶

Plants communicate via a language, using chemical compounds: ‘each compound transmits precise information, such as warnings of imminent danger, or messages of attraction or repulsion, or something else’.¹²⁷ Calvo and Lawrence write that more than ‘1,700 different volatile cocktails’ in the plant language ‘lexicon’ have been identified, and that the behaviour of plants ‘can change dramatically as a result of the messages being exchanged’.¹²⁸

Recently, Khait and co-authors found that plants emit ultrasonic sounds, resulting in the first sound recording of tomato and tobacco plants.¹²⁹ The significance of these sounds, however, is still very much open for debate. Possibly, they are the equivalent of ‘bodily’ sounds one can also hear inside animals, such as bowel sounds, heartbeats, and flowing air.¹³⁰ What has been demonstrated is that plants can register sounds from their environment. When playing a recording of sounds emitted by leaf-nibbling caterpillars, Thale cress (Arabidopsis thaliana) responded by activating its chemical defence mechanism.¹³¹ Recordings of wind and insect song did not cause this reaction, which suggests selective responses to sound.¹³²

Through their ability to communicate with other plants,¹³³ as well as with animals,¹³⁴ plants form partnerships with both plants and animals.¹³⁵ These partnerships may be mutually beneficial. For example, parasitoid wasps are attracted by chemical compounds that plants emit when attacked by herbivores.¹³⁶ Furthermore, some ants defend plants in return for nectar.¹³⁷ One may even entertain the thought that humans are in a partnership with plants that they take care of because they find those plants beautiful, delicious or otherwise useful.¹³⁸ As Attenborough phrases it, plants like soy, wheat, and rice ‘persuaded us to eliminate their competitors, cure their diseases, poison their enemies, and keep them well-watered even when other species faced drought’.¹³⁹ Benton writes that ‘[f]lowers, as has often been said, are the plant's way of enslaving bees, moths, bats, and other pollinating animals’.¹⁴⁰ Like certain animals, plants too can be deceptive in their partnerships. Orchids, for example, trick male insects into carrying around plant pollen without giving the insect something in return.¹⁴¹ To be sure, ‘mere’ evolution by natural selection – as opposed to conscious cognition or active choice – has facilitated many of these phenomena.¹⁴²

It could also be said that plants can make ‘plans’ for the future by estimating risks and benefits and ‘investing’ accordingly – such as through the ubiquitous ‘escape from shade’ behaviour that plants exhibit: they spend a great deal of energy, which is risky, ‘expecting’ to end up with benefits (sunshine).¹⁴³ The philosopher Hegel observed with interest such behaviour in potato sprouts as he watched them ‘climb up the wall as if they knew the way, in order to reach the opening where they could enjoy the light’.¹⁴⁴

In short, as summarized by Mancuso and Viola, ‘plants eat without a mouth, breathe without lungs, see, taste, feel, communicate, move, despite lacking sensory organs like the ones we do’.¹⁴⁵ They ‘defend themselves from predators by using complex strategies’, ‘circumvent obstacles, help one another, can hunt or lure animals, move to reach food, light, oxygen’.¹⁴⁶

As noted earlier, whether all this is ‘merely’ (intentional) behaviour or actual sentience is still being debated. Then again, animal sentience and even human free will are still being debated. In the light of scientific findings, some of which have been mentioned above, the sentience of plants deserves at least to be considered as a rationale for their de-objectification in private law.

In the next two subsections we discuss other possible rationales for de-objectifying plants: one that goes further than plant sentience (plant intelligence) and some that could be accepted instead of plant sentience – the precautionary principle applied to plant sentience, intrinsic value (or dignity), and plants as fellow beings (or aliveness, or common sense).

3.4. Plant ‘Intelligence’

The question of plant ‘intelligence’ is more contentious than that of plant sentience, and we want to stress that intelligence is not a necessary condition for de-objectifying plants in private law (nor is it for animals, after all). It is nonetheless an interesting potential rationale for de-objectifying plants. Do (some of) the examples of plant sentience also imply intelligence? That depends upon, among other things, how prepared one is to see ‘intelligence’ in ways that differ from the day-to-day connotation the term has in its human context.

Bridle, in his 2022 book Ways of Being, argues that ‘many different kinds [of] intelligence … have been here, right in front of us, the whole time – and in many cases have preceded us’, and that ‘Western science and popular imagination, after centuries of inattention and denial, are only just starting to take them seriously’.¹⁴⁷ Bridle writes that ‘[i]ntelligence, it seems, is something physical and relational, not a wholly abstract process, but one closely tied to our being and doing’,¹⁴⁸ and that ‘plant intelligence, whatever it is, is plant-y’, something that humans will never be able to fully understand.¹⁴⁹ Marder points to certain authors’ ‘calls for judging intelligent behavior in non-human organisms based on the capacities of the organism in question’ and that, in this spirit, ‘plant intelligence refers to what plants can do as well as to their unique perspective, expressed at the cellular, organismic and environmental levels’.¹⁵⁰ He suggests adopting a ‘plant point of view’ when considering the (supposed) intelligence of plants, for he feels that the field of biology ‘must investigate the particular perspectives correlated with each distinct form of life’.¹⁵¹

Such an understanding of intelligence – as something that comes in many forms and must be appreciated in the context of a particular species – has also been put forward in writings on animal intelligence. Primatologist De Waal tellingly titled one of his last books Are We Smart Enough to Know How Smart Animals Are? ¹⁵² Balcombe, writing about sentience and intelligence in fish, relays that ‘[t]he modern scientific field of cognitive ecology recognizes that intelligence is shaped by the survival requirements that an animal must face during its everyday life’;¹⁵³ and that one is to heed ‘the plurality and contextuality of intelligence, the fact that it is not one general property but rather a suite of abilities that may be expressed along different axes’.¹⁵⁴ Balcombe appreciates the species-specific characteristics of fish precisely because ‘they are not like us’, writing that ‘[t]heir different ways of being in the world are a source of fascination and admiration, and cause for sympathy’.¹⁵⁵ In the 16^th century, Michel de Montaigne pondered: ‘The defect that hinders communication betwixt [animals and humans], why may it not be on our part as well as theirs?’¹⁵⁶

One needs to remain mindful of the possibility that ‘intelligence’ is projected by humans on processes that could be partially, mostly, or entirely ‘mechanistic’,¹⁵⁷ and that a more prudent interpretation of plant behaviour should not be cast aside too rapidly.¹⁵⁸ With animals, too, some scientists have been too keen to anthropomorphize their supposed intelligence, Darwin being an important example.¹⁵⁹ Alpi and co-authors express appreciation for the field of ‘plant neurobiology’ as ‘an initial forum for discussions on the mechanisms involved in plant signaling’, but warn of ‘superficial analogies and questionable extrapolations’.¹⁶⁰ As mentioned earlier, the science into ‘plant sounds’ in particular is far from settled.¹⁶¹ Wohlleben was criticized for using language, in The Hidden Life of Trees, ‘that is strongly anthropomorphic and teleological’.¹⁶² On the other hand, De Waal feels that ‘even in the case of [distantly related species], anthropomorphic explanations deserve serious attention’.¹⁶³ Calvo and Lawrence caution against ‘two extremes: the anthropomorphic tendency to see ourselves in things that are entirely unrelated, and the anthropocentric refusal to acknowledge continuities that exist between ourselves and other forms of life’.¹⁶⁴

Dennett, who came up with an interesting taxonomy of competences in living beings,¹⁶⁵ is sceptical of the supposed capabilities of plants, stating that plants do indeed have competence and intentional behaviour, yet lack ‘comprehension’.¹⁶⁶ He cautions that humans wrongly assume that just because our own ‘behavioral competence’ comes with comprehension, the intentional behaviour that plants exhibit thus also must come with comprehension.¹⁶⁷ Humans, Dennett posits, are ‘anthropomorphizing the plants … in order to understand them’.¹⁶⁸ Dennett, however, is also sceptical of comprehension in non-human animals, even in ‘“higher” species such as mammals and birds’.¹⁶⁹ This would mean that – to briefly return to considerations on sentience – if animals can be de-objectified on the basis of sentience, as has been done in various civil codes, Dennett's diagnosis that plants are competent but do not comprehend would not necessarily bar plants from being de-objectified.

In 1974, Feinberg argued that ‘all are agreed that plants are not the kinds of beings that can have rights’ as they have ‘no conscious wants or goals’ and thus ‘cannot know satisfaction or frustration, pleasure or pain’.¹⁷⁰ To be able to have an interest, Feinberg contended, a living being needs to have ‘at least rudimentary cognitive equipment’.¹⁷¹ However, in the decades since Feinberg wrote this, plants (in the form of forests, for instance) have indeed been given rights.¹⁷² Furthermore, one could argue, as Eskens does, that living beings have ‘interests’ when their behaviour shows effort.¹⁷³ Plants do arguably show effort in their behaviour and pursuit of their biological needs. Calvo and Lawrence write that plants exhibit ‘adaptive, flexible, anticipatory, goal-directed behaviour’,¹⁷⁴ and that they, like animals, ‘move through their environments, collecting information as they go’,¹⁷⁵ ‘deploying their evolved toolkit of sensory abilities and behaviours as they interact with the living and inert world around them’.¹⁷⁶ Plants, they write, ‘keep a constant eye on a number of parameters as they fluctuate in real time’, and may, ‘[a]fter judicious cost-benefit analyses’, ‘triage’,¹⁷⁷ and ‘decide where to invest their precious metabolic resources’.¹⁷⁸

As noted earlier, whether one believes that plants might possess intelligence is ultimately not crucial for our argument for de-objectifying plants in private law. After all, sentience could (and does) exist apart from intelligence, and sentience as such would still be ample ground for their de-objectification.

However, should accepting plant sentience prove to be a bridge too far for some legislators, there are still other possible rationales for de-objectifying plants in private law, which we discuss briefly in the next subsection.

3.5. Other Rationales for De-objectifying Plants in Private Law

Firstly, the precautionary principle could be applied to plant sentience. Remarkably, chemicals like histamine, serotonin, dopamine, and gamma-aminobutyric acid (GABA) – all of which function as neurotransmitters in many animals, including humans – are also found in plants, and quite possibly play a significant role in the electrical signalling in plants.¹⁷⁹ Countering the argument that sentience requires certain typical animal features such as a central nervous system or a neocortex, Browning and Birch argue that there is ‘no evidence against the possibility that similar subjective experiences can be generated by very different mechanisms’.¹⁸⁰ Our lack of understanding of this so-called ‘multiple realizability’ of sentience could support applying the precautionary principle.¹⁸¹ Without absolute certainty, which will never be attained (not even when it comes to questions on human sentience, consciousness or free will), we should give plants the benefit of the doubt, in line with the precautionary principle.¹⁸² Even while the debate is still raging, the findings from plant science strongly support the idea that plant sentience is a realistic possibility. Are we smart enough to know how sentient plants are?

Secondly, one could consider a plant's intrinsic value or dignity as a ground for distinguishing a plant from a mere object. In 2008, based on the available scientific evidence, a committee of the Swiss Federal Assembly considered the ‘dignity’ of plants, which, according to Pelizzon and Gagliano, can be regarded as ‘the first legislative initiative to mandate “moral consideration of plants for their own sake”’.¹⁸³ Mancuso and Viola view the Swiss initiative as one that lays the groundwork for future plant rights; it could then perhaps also serve as groundwork for the future de-objectification of plants.¹⁸⁴ Philosophically, the concept of intrinsic value, which as mentioned is important in the Dutch context, is too complex to do justice to in this article. However, it seems safe to say that, legally, in many jurisdictions, plants are already held to have intrinsic value. The 1979 Convention on the Conservation of European Wildlife and Natural Habitats (Bern Convention), for example, explicitly refers in its preamble to plants (‘flora’) as having ‘intrinsic value’.¹⁸⁵ The Convention on Biological Diversity (CBD) also considers plants to possess intrinsic value, albeit implicitly.¹⁸⁶ The point of view expressed in the Bern Convention and the CBD, which have been ratified by almost all eligible states, could arguably be grounds for de-objectifying plants in private law.

Thirdly, plants are not objects in the common sense of the word. The German Animal Protection Act, as mentioned, refers to animals as our fellow living beings. Plants surely are our fellow living beings, too. The very fact that plants are alive can thus suffice as a basic rationale for de-objectifying them. Common sense suggests that plants, being alive, are not objects or things. Why not acknowledge this in private law? At the very least, it would codify the expansion of the citizenry's moral circle of empathy and consideration.

4. Expanding the Circle

Singer describes the historical development of human morality as an expanding circle: as (and in so far as) people ‘progressed’, they kept expanding (although also often retracting) their sense of consideration for and altruism towards people and entities other than their own individual self.¹⁸⁷ Darwin, too, in his Descent of Man (1871), wrote that the circle of ‘sympathies’ around people's own personal self continued to grow as time progressed.¹⁸⁸ Consequently, these developments in morality often translated into law.¹⁸⁹ As it expanded, the circle came to include more and more (groups of) people, human institutions, and animals. Most of the academic legal literature on expanding the circle to cover plants has focused on rights of plants or RoN, which is why some of this literature, as well as other relevant sources, will be discussed in the following paragraphs.

The concept of plant rights, like animal rights, is still in its infancy in Western jurisdictions. As mentioned, Marder writes that ‘Eastern’ philosophies ‘have been at the forefront of protecting plant life for millennia’ and might offer ideas for Western debates.¹⁹⁰ In European parliamentary discussions, plant rights have been considered only sporadically. In 1993, a member of parliament for the party GroenLinks (Green Left) in the Netherlands asked: ‘Who can defend the rights of plants, animals, and future generations, if not the government that should concern itself with these interests in the light of the common good?’.¹⁹¹ Tribe wonders if people will want to afford rights to plants as they would to animals.¹⁹² Marder, on the other hand, claims that expanding the circle to plants would not be ‘a radical break’ with current practices, but ‘a relatively minor adjustment’, a ‘fine-tuning’.¹⁹³

The ability to suffer or experience pain has also been offered in support of the position that (some) rights should be given to plants. Marder writes that ‘sentience and the ability to feel pain’ was the yardstick that suggested that (certain) animals should have the Arendtian ‘right to have rights’.¹⁹⁴ Tribe noted in 1974 that ‘[s]ome research even suggests that plants exhibit electrical and chemical reactions which are functionally analogous to pain’.¹⁹⁵ This has been suggested in various studies, including the 2023 ultrasonic sound experiment mentioned earlier, in which the sounds of stressed plants (after cutting or drought) appeared to be different from those of healthy plants.¹⁹⁶ Again, it is still uncertain whether those sounds can indeed be likened to utterances of pain.¹⁹⁷ Draguhn, Mallatt and Robinson state that ‘plants do not possess the molecular and structural machinery for pain generation’.¹⁹⁸ Petruzzello, too, writes that plants ‘do not feel pain as we members of the animal kingdom understand it’, although she stresses that ‘it seems that many plants can perceive and communicate physical stimuli and damage in ways that are more sophisticated than previously thought’.¹⁹⁹

In a 2023 study, plant signalling responses to injuries were visualized.²⁰⁰ One consideration mentioned in the (biological) literature about future rights pertains to experimental testing on plants; the suffering induced by experimental testing on animals was, after all, an important factor in the struggle for animal rights.²⁰¹ As mentioned earlier, plants possibly experience stress when grown in transparent gels for biological research purposes. Being aware of their possible susceptibility to stress, the important question in relation to plant rights is whether, therefore, plants can be said to ‘suffer’, and, if so, whether humans care to expand their moral circle of empathy and consideration as a result.

Aside from some trials during the Inquisition where plants like fennel and garlic were believed to be accomplices of witches and therefore put on trial,²⁰² there have been hardly any instances where the (intrinsic) rights of plants themselves have been considered judicially. However, the rapidly proliferating RoN movement deserves attention in relation to plants. While some cultures and ontologies have a long tradition of recognizing RoN, even Western legal systems, which at first sight seems rather unwelcoming to non-humans, may now expand their circle by the granting of legal personhood, legal standing and/or representation through a board or trust to non-human individuals or collectives.

Despite RoN being far from uncontested,²⁰³ the first examples of RoN (often also covering plants) have now been brought into existence, whether constitutionally,²⁰⁴ legislatively,²⁰⁵ or judicially.²⁰⁶ Attempts to grant legal personhood to individual plants so far have largely been unsuccessful. For example, the Belgian Tribunal de Première Instance Francophone in Brussels denied the admissibility of 82 individual trees as plaintiffs in a climate case.²⁰⁷ However, wild rice (Zizania palustris), ‘manoomin’ in the Indigenous Ojibwe language, was granted ‘inherent rights to exist, flourish, regenerate, and evolve’ in a 2019 tribal law of the White Earth Nation in the state of Minnesota.²⁰⁸ This law protects the wild rice itself, its ‘freshwater resources’, as well as the ‘habitat of the rice’.²⁰⁹ When the rights of the wild rice are violated, a lawsuit can be brought, with manoomin being the ‘the real party of interest’.²¹⁰

However, with far-reaching rights, such as the right to habeas corpus for chimpanzees mentioned earlier, it is difficult, if not impossible, to form an analogy between animals and plants: chimpanzees are highly self-aware and autonomous creatures, which have a ‘theory of mind’.²¹¹ They have a notion of time and know that when they are imprisoned today, they will or can still be imprisoned tomorrow, which leads to suffering.²¹² These characteristics, which were put forward as legal arguments in the court cases regarding chimpanzee standing, are not proven to be common in all animals, and also do not appear to be present in that way in plants.²¹³

Several authors, mindful of the ‘slippery slope’ argument, stress that the discussion of the rights of plants need not frighten people into thinking that someone who picks a flower could someday be charged with a criminal offence. Biochemist Koechlin says that we can keep eating and using plants, but that humanity merely has ‘some’ responsibility towards plants.²¹⁴ People, according to Koechlin, violate plant dignity in certain specific circumstances, such as genetically manipulating plants to be sterile so corporations can keep selling new specimens, or patenting plants.²¹⁵ Also, Koechlin believes, ‘plants should have some degree of independence regarding their adaptation and propagation, as well as the survival of their own species’.²¹⁶ Koechlin and co-authors furthermore have proposed ‘the Rights of Plants’ in several theses – known as the ‘Rheinauer Theses’ – which form the most elaborate proposal for rights of plants that we have come across.²¹⁷ They vary from the right not to be baselessly subjected to ‘[m]ethods and strategies that cause sterility’, to the right to survival as a species, to the right not to be patented.²¹⁸

Koechlin and co-authors state that ‘[p]lants are not objects’;²¹⁹ they ‘are living beings’.²²⁰ We agree with these two theses, as has hopefully become clear. Yet, unlike Koechlin and co-authors and other voices mentioned in this section, we do not argue for rights of plants, but for de-objectifying them in private law.

5. Conclusion

Plants are fascinating organisms. Their instrumental value alone is immense, since they facilitate most animal life on Earth, form the basis of our food and energy chains, absorb CO₂ and certain pollutants, and ameliorate our daily lives in myriad ways. For eons now, plants have existed on this planet in a manner that is foreign to animals in general and humans in particular, and we should thus be mindful not to anthropomorphize them. Nonetheless, there is ample indication that humans have underestimated and undervalued plants for a long time and in many ways, and that their value goes beyond just the instrumental.

In the more than 150 years since On the Origin of Species was first published, public perception of animals has undeniably changed. We now know that humans, animals, and plants share the same ‘lowly origin’.²²¹ This realization eventually trickled down more and more into law. Since 2004, over 1,000 animal protection laws have come into force in the US alone, ‘a number that rivals all of the animal protection laws enacted in American history prior to 2000’.²²²

As we have argued, scientific discoveries about the various abilities of plants are causing our perception of plants to change, too. Another expansion of our moral circle could therefore include plants, by de-objectifying them in private law. Acknowledging that plants are living organisms – either with or without sentience and/or intrinsic value and dignity – rather than mere objects/things, would not necessarily lead to the bestowing of rights on plants. As mentioned above, de-objectifying animals in civil codes never necessitated fundamental changes to animal exploitation. There is no reason to believe that de-objectifying plants would be a legal Trojan horse that would make gardeners unemployed or force violin makers to continue their practice underground.

However, it would not be a dead letter either. From jurisprudence, it follows that the upgraded position of animals in civil codes causes judges to pay more attention to the wellbeing of the animal at stake. Equivalent to what Burdon and Williams write regarding bestowing actual rights, one could well say that de-objectifying plants in private law could not only (help to) provide governmental protection, but also an increased visibility and awareness of and respect for plants.²²³ Bernet Kempers points to the noteworthy implications of de-objectifying animals in private law, such as influencing the way in which private law addresses animals, as well as regulating what human persons may or may not do with (certain) animals.²²⁴ Similarly, this could serve numerous instrumental purposes for plants. Possibly, the legal de-objectification of plants could lead to, for instance, better protection of specific individual plants,²²⁵ wider impact across entire plant species or even ecosystems, perhaps through the germination of a Plant Act as an equivalent to the various pieces of animal-related legislation.²²⁶ Furthermore, the acknowledgement in private law for plants would contribute to the broader spirit that also feeds the calls for plant rights and Rights of Plants.

As such, for those who argue for meaningful steps towards incorporating non-human life into law, putting plants in the ‘in-between category’ could serve both as an inspiration and as a potential building block for later developments around plant rights and RoN in a broader sense. It could open up the conversation and broaden the legislative and political horizon. For those who are more sceptical of actual plant rights and RoN, the de-objectification of plants in private law could serve as a middle road. After all, amending a provision in the civil code is a feasible step to take, as the path for such an amendment has already been paved by the process of de-objectifying animals. Placing plants in the ‘in-between category’ in private law would not be scientifically, politically, or legally radical; and it would create possibilities without obligating anything. It would merely plant a seed, which then might blossom into something fruitful, or wither in infertile soil.

Considering the arguments for plant sentience mentioned above, it is peculiar that plants are still commonly seen as practically inanimate phenomena – not much more indeed than the ‘(corporeal) objects’ central to property law – that are not worthy of our consideration. Acknowledging in private law that plants are different from mere objects (or things) would to us seem to be in concurrence with science, and it would at least symbolically reflect an evolved and grown-up understanding, on the part of the citizenry, of the special worth of vegetable forms of non-human life – forms of life, incidentally, that make it possible for us to be alive in the first place and with which we share a common ancestor.